MATTNOYES.NET - Weather Website & Blog

Drier...Breezy...Little or No Additional Damage Expected

Welcome to the weather blog! While the web address has changed, the blog will still be the same Monday through Friday discussion - with some improvements! Over the course of the next few weeks and months, you'll find me experimenting and adding new features. Maps, pictures, and other multimedia are enhancements I'm hoping to be able to make as I learn more about how to maximize the new site. Format will be similar to the old version - you'll find a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow. If no technical discussion is available when you check in during the morning, check back later as it often comes after the Weather Summary - I try to indicate at the end of the general weather summary when/if a technical discussion is coming. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

For latest radar imagery, to check for watches and warnings, and for links to sites in the world of weather, feel free to click over to my website: www.mattnoyes.net

Matt's Weather Summary: 

6:15 PM:  Please monitor NECN for updates on the following situation: About 2,000 people are now being evacuated from their homes in Taunton, Mass. - due to possible structural problems with the Whittenden Dam. Anyone near the dam is asked to move to higher ground or to a temporary shelter at Taunton High School.

After a busy weekend of flooding followed by wind damage, things will begin to quiet down in the weather world today.  The moisture and energy that brought the flooding rains to New England this weekend merged to form a powerful storm center just northeast of Maine, and it's this storm that delivered the shot of powerful Sunday winds.  As this storm very slowly weakens and drifts eastward, away from New England, today, winds will still gust over 30 mph regionwide, but that's significantly weaker than the 40 to 50 mph winds from Sunday, and the threat for damage should be behind us now.  As for flooding, those rivers that have not yet receded will begin to do so during the day on Monday, except for portions of the Connecticut river and a few other exceptions.  Later this morning, I will update my flood page, linked off of the main www.mattnoyes.net webpage.

So how about the weather from here on out?  The overall pattern of the jet stream is going to change markedly for the next week.  Remember that the jet stream is the fast river of air aloft in the atmosphere that steers our storm systems and acts as a thermostat, separating cool air to the north, from warmer air to the south.  The jet stream for the past several days has been pumping in warm and moist air aloft from the Tropical Atlantic, but now has shifted to a pattern that flows from Northwestern Canada to New England.  This will keep energetic but fast moving storm centers diving across New England through the week, each delivering a shot of slightly cooler air.

The first fast-moving jet stream disturbance to affect us is moving across the Great Lakes Monday morning.  As it continues its push eastward, it will help to kick out the large storm east of Maine, but not before this departing storm throws back enough moisture for another round of showers in Northern Vermont, New Hampshire and Maine Monday afternoon between breaks of sun.  Farther south, a blend of sun and clouds will rule the roost for Monday, where there simply won't be enough moisture available for showers to develop.  But a new incoming disturbance will also mean we don't have much time to enjoy entirely quiet weather.  As this new disturbance moves east with its attendant low pressure center and cold front, clouds will thicken Monday night and winds will swing around to blow out of the southwest.  These southwest winds will bring a breezy day on Tuesday, and while they will be ushering in a warmer airmass, with lots of clouds and a few showers around - especially from mid-morning through mid-afternoon, and throughout the day in Northern New England - high temperatures will be hard pressed to rise much beyond 60, even as the sun tries to break through by late Tuesday afternoon.

Wednesday begins with sunshine after a cool and quiet night Tuesday night, but yet another disturbance at the jet stream level will be swooping in from Canada, caught in the fast winds aloft.  This means clouds should increase yet again Wednesday afternoon.  This time, however, it appears as though there won't be much moisture to squeeze out in Southern New England, and right now I'm thinking any showers will be confined to the North Country late Wednesday and Wednesday night.  The problem for Northern New England is that...with each disturbance pulling through a cold front at the surface...enough cold air may be in place by late Wednesday night into Thursday morning for snow to fall close to the Canadian border.  At this point, it's not looking too significant - just a sure sign that winter's not far away.

For the rest of us, the passage of Wednesday Night's cold front may be dry, but it still marks the leading edge to a reinforcing shot of cool air that will bring breezy and brisk conditions on Thursday.  In this fast flow of weather disturbances, clouds will thicken again later Friday with rain showers possible Friday night into Saturday, then a steadier rain on Sunday (not our weekend!!) as another jet stream disturbance and the associated surface low pressure center move through.  It's still early, though, and I don't like the idea of rain on my weekend anymore than you do, so let's give it time and see what happens.

Have a wonderful Monday!

Technical Discussion:  See Below.

Matt

Matt's Technical Meteorological Discussion:  Updated Monday, October 17 at 3:30 PM

River flood page has been updated for the final time for those of you looking for everything in one place.  Will likely remove the link from mattnoyes.net main page later Tuesday.

Transition to fast flow is underway as upper low east of Maine will pull east and decay while broad weestern ridge/eastern trough pattern sets up across the northern tier of the US.  Caught in the fast jet stream flow will be multiple energetic shortwaves that will dive SE across NewEng the next several days, with the amount and intensity of precip they produce dependent largely on available low-level moisture.  This broad northeast troughing will persist until the middle to end of the last week of October as lower heights are left in the wake of the current large cyclone and serve as a sink for shortwaves ejecting east from the monster energy diving over and S of Alaska to create a rather intense Aleutian low.  While 500 mb heights will remain anomalously high over Northern and Central Canada, effects of the season are enough to result in building cold air across the higher latitudes.  Therefore, as energy ejects east and then southeast across Canada heading for NewEng, it will bring with it installments of cool air through the end of October.  Thereafter, signs are for the Aleutian low to weaken but remain intact, keeping ridging across the Intermountain region and weak troughing in the Northeast.  But the cold shots over the next two weeks may largely exhaust what's available for cold air in Central Canada, and with high heights in that region, warmth building across the western US may morph into a larger scale near to above normal temperature regime for the US, with the Northeast on the outer fringes and still subject to modified cool shots with our weak persisting trough.

Those are my thoughts on the overall longwave pattern, but in the short term winds today are going to gust over 30 mph most areas - some over 35 - but not high enough for damage in most spots.  Sunday's 45-50 mph gusts (some higher) were enough to do most of the damage.  Still, mentioned that today's winds are enough to cause problems for construction sites, those with tents, and those with banners outside.  Tons of low level moisture lingers in the north as well as upslope flow, hence the clouds throughout the day while Southern New England enjoys sunshine excepting the Berkshires and areas downwind of the Berks where upslope developed clouds are being carried by the WNW wind flow.

Tonight skies clear in Central/Southern NewEng briefly but increase again in advance of shortwave and associated low pressure center.  Should be a period in Southern NewEng with slackening winds and mainly clear skies which allows temps to drop into 40's...farther north the low level clouds hang on longer and by the time they break up high clouds are streaming in and winds are ready to shift to SW and increase so uniform 40's.

Tuesday intense vort and crashing heights cross NewEng.  Increased instability with cooling aloft means plenty of clouds thru the day most spots, tho drying aloft works in behind the vort late and some parts of SW NewEng especially may break clouds to sun before sunset.  SW wind tries to advect surface warmth but with most of NewEng hard pressed for sunshine, temps will not be eager to rise.  Based on forecast of sunshine breaking thru late, we can get low 60's Southern NewEng, but 40's and 50's north under day-long clouds.  Most areas of NewEng see showers with period of greatest dynamic forcing and cyclonic vorticity advection from mid-morning thru early to mid-afternoon.  Feature which may have some effect would be surface wave of low pressure developing under the vort and traveling from BTV to Gulf of Maine Tuesday 18Z to 00Z.  This will probably keep mid and Downeast coast of Maine locked in fog most of day as well...at least until winds shift behind wave late.

Morning sunshine mixes atmosphere to bring temps back near 60 on average for Wednesday, but I'm not buying widespread mid 60's MOS guidance is touting just yet.  Too much chill comes in behind Tuesday's shortwave to retreat it so quickly even with warm advection ahead of Wednesday night's shortwave.  My initial thinking was that, without much moisture available, we may even see a dry frontal passage in Southern NewEng but I'm reconsidering give 850 Theta-E shows plume of moisture straight out of the Pacific comes across Plains and OH Valley and interacts with front.  This moist tongue may penetrate far enough northeast to produce precip.  Farther north, enough energy for strong forcing to crank out rain showers that will change to snow showers later Wednesday night into Thu AM along the Canadian border.  Thursday morning an extended period of snow showers is likely in Northern NewEng with the combination of a shot of cool air to the tune of -6 C at 850 mb and upslope flow.  Otherwise, downsloping combined with drying brings the sun back out in Southern NewEng and along the coastal plain.

Looks like sun's back on Fri AM, but next in the line of shortwaves is ready to truck into NewEng Friday night into Sat - so clouds increase late Fri and rain develops Fri Ngt and lasts off and on thru Sat.  This may not be the innocuous shower event it appears to be at first glance - this energy is the remnant of the UL low over Southern CA today, and will feed off of it's own moisture that it's currently pumping in from the Pacific.  With such a fast and active flow in the Northern stream, there is every opportunity for this Southern stream low to merge with one of the energetic shortwaves embedded in the northern flow.  In fact, multiple Ensemble members are picking up on this possibility and cranking out a heavy rain event for most of NewEng Saturday into Sunday as ridging amplifies over the Rockies.  This amplification relates back to the strengthening Aleutian low mentioned at the start of this discussion - with an amplified Eastern Pacific trof, the Rockies ridge has no choice but to amplify in response.  Following this longwave pattern, this favors a pulse deepening of the SE Canada/Ern US trof, which will allow for yet another storm to crank up vicinity NE US.  Canadian Ensembles also keying in on this potential and are likely significantly underforecasting potential QPF amounts at this early juncture, marking the axis of heaviest precip from SE NY to Nrn ME with .50", but right now I'd throw that amount away, because this will either be a non-event, or a heavy QPF event and I think we're only seeing the beginning of what will be a wet and wild trend.

Part of the reason for this expected trend is that we, of course, we have Wilma to contend with, and perhaps not just Wilma.  Given time constraints, I will bypass a complete tropical discussion on Wilma and the other tropical features, but we have two areas of disturbed weather that I'm most interested in over the Tropical Atlantic - one northeast of Puerto Rico and the other east of the Leeward Islands.  As for Wilma, even if she passes over Honduras and is degraded - which I'm not sure will be the case given that her center lay to the north of the deep convection - while she would be torn apart she would come back over the still-warm waters of the Gulf of Mexico, and a strike on the Northern Gulf coast...at this point...seems like a pretty decent solution given the repetitive shortwaves diving into the Lower MS Valley by this weekend with the only-just-begun-to-amplify trough (just getting going Saturday).  Additionally, the ridge holding firm over the Central Atlantic will not allow the circulations mentioned above to move northward and away from the US - they have two choices this week by the Leeward Islands:  1) Decay and become a non-player, 2) Move westward.  At least one of these circulations should move west and hold together, if not both, though they may have different compositions, as the circulation northeast of the islands currently is non-tropical aloft and only now trying to spin up deeper convection from time to time and failing.  This upper low looks unfavorable to become tropical right now, though it has an extremely important role in enhancing outflow on the northeast side of Wilma, which is so impressive it's resulting in convective bands removed well NW of her center.  There are two waves located east of the Leeward Islands that are moving west, and indications are that as the leading wave encounters the upper low mentioned above, it will slow and the second wave will be the feature of concern.  Though by the time this feature moves far enough west to become a player it may be too late...then again, it may not.

Too late for what?  As mentioned above, Wilma looks like eventually she is going to have to come north with a weakness developing in the ridge north and northwest of her.  The problem is that as she starts to come north the trough deepening explained above is already underway from the Great Lakes to the northeast.  Remember what we've reviewed in these discussions in the past - deepening upper lows will serve as a sink when the pattern becomes amplified.  The concern here is that the developing upper low becomes a sink ready to pull Wilma - and perhaps the additional wave east of the Leeward Islands - north/northeast and northwest, respectively.  Whether this all happens at once, or one piece at a time it is too early to say, but one would have to think whatever is left of Wilma is not going to be able to ride due north over or west of the Appalachians with the height falls that will be occurring over the Ern US, and instead will have to come north to the Gulf coast, hook northeast, then would feel the effects of the Northeast upper level sink, perhaps pulling the aforementioned wave in as she curls around or over the Southeastern US.

All of this is largely speculation given variable speed of both northern and southern stream waves, and Wilma, but it's going to be hard to see such anomalously low heights over the Eastern Lakes and Northeast, and NOT see at least some of this energy and moisture be pulled into the northeast.  If that's not food for thought for you, not sure what is!

Have a good Monday.

Matt

Severe Flooding in Some Communities...Rivers to Overflow...Strong Winds to Topple a Few Trees Sunday as Sun Returns

Welcome to the weather blog! While the web address has changed, the blog will still be the same Monday through Friday discussion - with some improvements! Over the course of the next few weeks and months, you'll find me experimenting and adding new features. Maps, pictures, and other multimedia are enhancements I'm hoping to be able to make as I learn more about how to maximize the new site. Format will be similar to the old version - you'll find a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow. If no technical discussion is available when you check in during the morning, check back later as it often comes after the Weather Summary - I try to indicate at the end of the general weather summary when/if a technical discussion is coming. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

For latest radar imagery, to check for watches and warnings, and for links to sites in the world of weather, feel free to click over to my website: www.mattnoyes.net

Matt's Weather Summary: 

Sunday Morning Status:  No blog today, but feel free to read the discussion from yesterday.  Blog will resume Monday morning, but forecast (at left) and flood page (linked off of main page) remain updated.  Enjoy your Sunday!  -Matt

Special weekend post for ongoing severe weather and localized life-threatening flooding.

Please note this discussion is a weather overview and very general in nature.  Go to my homepage, www.mattnoyes.net, and click on the special flood link I've posted for details regarding river flooding, a few significant flooding updates otherwise.  Also on the main page you'll find links to radar imagery from across New England so you can follow the rain yourself.  Flooding has been quite serious in the City of Worcester, MA, and evacuations/rescues have been ongoing.  Details on the flood page and on NECN. 

For most of Central and Southern New England, lingering heavy rains this morning will continue to draw to a close.  By late morning things will have tapered down for these areas and by late in the afternoon, the sun will be trying to break through.  I'm hopeful that with some finger crossing, Southern New England will end the day with a blend of sun and clouds, with clouds and showers holding on in the mountains, and periods of heavy rain continuing through most of Maine as a strengthening storm center moves northward, passing east of New England and redirecting the flow of tropical moisture into the State of Maine, where urban flooding and flooding of small rivers and streams will be possible later Saturday into Sunday morning.  Winds actually may be light for a time in Central and Southern New England this afternoon, so where the sun does break through, we may see a pretty nice period of weather for a few hours!

By Saturday night, the storm center east of Maine really starts to wind up and actually "retrogrades," or moves westward to a position just north of Aroostook County.  This kicks winds up across New England, and by Sunday we may see some wind gusts over 50 mph in the hilly terrain of New England and at the coastlines!  The rest of us will be plenty windy, as well, with gusts to 40 mph, and I'd suggest that if you have a tent rented for an outside event, or banners, etc. that can catch the wind and act as a sail, be sure you've secured everything well and made preparations for strong gusts on Sunday.  Additionally, keep in mind the ground is now saturated from Friday night and Saturday's rains, which means we're going to be concerned that trees may become uprooted in these strong wind gusts easier than with dry ground.  As for sun vs. rain, most of us will start out sunny Sunday morning, but clouds will work back in during the afternoon, and with cold air aloft, we'll see what's called "instability" in the world of meteorology - a difference between relatively warm air at the surface and chilly air aloft that's a favorable setup for some sprinkles and scattered showers to develop during the afternoon.  Across Northern New England, plan on lots of clouds, periods of rain, and - a few thousand feet in elevation across the mountain peaks of far northern Vermont, New Hampshire and Maine, it's not impossible we find a few snowflakes by Sunday evening.

Next week begins with a continuing gusty wind - probably not as strong as Sunday's expected winds, but still a blustery day with sun, clouds, and a few of those instability showers.  A cold front will move through New England later Tuesday, bringing breezy conditions, afternoon showers, and a mid-week shot of cool air.

Have a wonderful weekend - back at it again on Monday!

Technical Discussion:  See Yesterday's Technical Discussion.

Matt

Wet Pattern to Transition to Windy Pattern

Welcome to the weather blog! While the web address has changed, the blog will still be the same Monday through Friday discussion - with some improvements! Over the course of the next few weeks and months, you'll find me experimenting and adding new features. Maps, pictures, and other multimedia are enhancements I'm hoping to be able to make as I learn more about how to maximize the new site. Format will be similar to the old version - you'll find a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow. If no technical discussion is available when you check in during the morning, check back later as it often comes after the Weather Summary - I try to indicate at the end of the general weather summary when/if a technical discussion is coming. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

For latest radar imagery, to check for watches and warnings, and for links to sites in the world of weather, feel free to click over to my website: www.mattnoyes.net

Matt's Weather Summary:  Welcome to your Friday!  Our weather synopsis this morning finds a wave of low pressure sitting south of Long Island, pumping several inches of rain into Long Island.  Those of us in Southern Connecticut and through the Hartford area have been on the northern edge of this heavy rain, and winds aloft in the atmosphere would favor steering this area of heavy rain toward the east-northeast while weakening it.  This means heavy rain will gradually shift from Connectiuct, through Rhode Island and Southeastern MA over the course of Friday morning.  Meanwhile, the remainder of New England will see periods of rain and showers with winds lighter than the past couple of days - something we're thankful for because this should limit any potential coastal flooding at the time of high tide between 8:45 and 9:45 PM Friday evening to minor, and in some areas just splashover, from east-facing coastlines of Maine through Cape Cod.

At the same time we watch the moist area of low pressure south of us, a new disturbance at the jet stream level is approaching from the west today, and showers will fall in Vermont ahead of this disturbance.  In fact, over the course of the day Friday, while the heavy rains in Southeastern New England weaken, they will expand northwest to merge with this new disturbance.  As a result, while the rain won't be of the same intensity it's been in extreme Southern New England, a larger number of us will see raindrops falling.  Friday evening, the incoming energetic disturbance from the west of New England will begin to move overhead, and this will shift the focus of heaviest rainfall to areas north of the Massachusetts Turnpike, and overnight the heaviest rains will be centered over New Hampshire and Maine.  I'm expecting Friday morning rain totals in the hardest hit areas of Southern New England to run 1-2" by Friday evening, and for areas farther north that see rain Friday evening and overnight into Saturday, expect rain totals of 1" in Northern MA and Central VT, 2" in the Monadnock Region, Interior Maine and the Northeast Kingdom of VT, and 3" from the White Mountains through the mountains of Maine.  Locally higher amounts are possible, and these amounts would be enough for flooding problems from the Monadnock Region to the White Mountains to Central and Western Maine.

For most of Central and Southern New England, Friday night rains will linger into early Saturday morning, but by late morning things should have tapered down and the sun will be trying to break through.  Saturday afternoon will bring a blend of sun and clouds for most of Central and Southern New England, with clouds and showers holding on in the mountains, and periods of heavy rain continuing through most of Maine as a strengthening storm center moves northward, passing east of New England.  As the sun comes out, you'll notice in my forecast (at left) that temperatures will warm in response, and winds actually may be light for a time in Central and Southern New England - bottom line, we may see a pretty nice period of weather for several hours Saturday after the rain departs!

By Saturday night, the storm center east of Maine really starts to wind up and actually retrogrades westward just north of Aroostook County.  This kicks winds up across New England, and by Sunday we may see some wind gusts over 50 mph in the hilly terrain of New England!  The rest of us will be plenty windy, as well, and I'd suggest that if you have a tent rented for an outside event, or banners, etc. that can catch the wind and act as a sail, be sure you've secured everything well and made preparations for strong gusts on Sunday.  As for sun vs. rain, most of us will start out sunny Sunday morning, but clouds will work back in during the afternoon, and with cold air aloft, we'll see what's called "instability" in the world of meteorology - a difference between relatively warm air at the surface and chilly air aloft that's a favorable setup for some sprinkles and scattered showers to develop during the afternoon.  Across Northern New England, plan on lots of clouds, periods of rain, and - a few thousand feet in elevation across the mountain peaks of far northern Vermont, New Hampshire and Maine, it's not impossible we find a few snowflakes by Sunday evening.

Next week begins with a continuing gusty wind - probably not as strong as Sunday's expected winds, but still a blustery day with sun, clouds, and a few of those instability showers.  A cold front will move through New England later Tuesday, bringing breezy conditions, afternoon showers, and a mid-week shot of cool air.

Have a wonderful weekend - back at it again on Monday!

Technical Discussion:  See Below.

Matt

Matt's Technical Meteorological Discussion:  Updated Friday, October 14 at 9:50 AM

Wave of low pressure south of Long Island has been keeping moist flow into Srn half of CT this morning and this is gradually shifting ENE over RI and SE MA where mid-level steering flow would take it ahead of approaching Northern stream shortwave producing showers over NY and coming into VT as of this writing.  Interesting that rain is actually falling heavier than what one would think based on radar base reflectivities - even 25 to 30 dBz returns are representing moderate rain.  This also sheds light on the intensity of the rain under higher return echoes.

The midlevel flow governs movement of the packet of moisture over SW NewEng and Long Island this morning, but northern stream shortwave takes over later today and rain should fill in thru most of NewEng this afternoon.  By evening, heaviest rain falling north of the MA Turnpike as opposed to morning heaviest rain south of it, and by overnight tonight heaviest rain falling thru VT/NH/ME where dynamic forcing in area of cyclonic vorticity advection is greatest, and intersects with moist Theta-E advection in both the low and mid levels, and at nose of 700 mb jet.  It's important to note that for all the ridiculous and tremendously challenging model flips, flops, and constant disagreement, the one area of agreement among the guidance has been on this northern rainfall tonight into tomorrow morning, so confidence has actually been higher in this event throughout the forecasting period.  Now, of course, we'll see if that really means anything!

Good agreement also on rains lingering thru 8-10 AM Eastern MA to most of NH points east on Sat, but should break up quickly during that time frame and sun's out most of Central/Southern NewEng by midday!  With 850 T's still running either side of +11 C and 925 T's still running either side of +14 C, we technically could mix to 70.  It looks like some cooler air does try to bleed in at the boundary layer, though, so haven't gone nuts with this and think instead L60's Southern, 50's Northern will cut it.  Winds actually have to wait awhile before they crank as they'll have to wrap around the backside of the low and more significant cold advection has to be present to mix the winds down.  This begins Sat eve, and winds should start to pick up then, active through the overnight and as the storm really bombs north of Maine Sunday, winds may gust up to 50 in hilly terrain, widespread 35 mph.  In the General Wx Summary above, I've encouraged folks with tents, banners, etc. for outdoor events to be prepared for strong winds Sunday.  As for precip, cold air wraps in under belly of low pressure first, but warm advection wraps in aloft after that, so this keeps precip cranking in Northern ME, while Northern VT and parts of the White Mountains will see upslope flow for lots of clouds and showers.  Not impossible that upslope flow allows us to adiabatically cool the column enough for snowflakes in the mountaintops, as discussed yesterday.

Winds continue to be active Monday behind the low and again Tuesday ahead of new incoming shortwave.  Enuf instability still present Monday to warrant scattered shower threat, and Tuesday's shortwave is mean!  Lots of cyclonic vorticity advection means winds will likely be quite gusty, warm advection ahead of it may be more than currently forecasted, and could be some hearty downpours if not thunder depending on how much warmth we can advect in at the surface.  Midweek cool shot still to follow - not impossible to see wintry mix in Northern Maine as warm advection sets back in on Wednesday or Wednesday night, but it's early and everything would have to come together perfectly so we'll see.

That's all for this week - have a great weekend!

Matt

Rain Moving Slower Than Anticipated...Forecast Updates Should Be Monitored in "Play-By-Play" Weather Scenario

Welcome to the weather blog! While the web address has changed, the blog will still be the same Monday through Friday discussion - with some improvements! Over the course of the next few weeks and months, you'll find me experimenting and adding new features. Maps, pictures, and other multimedia are enhancements I'm hoping to be able to make as I learn more about how to maximize the new site. Format will be similar to the old version - you'll find a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow. If no technical discussion is available when you check in during the morning, check back later as it often comes after the Weather Summary - I try to indicate at the end of the general weather summary when/if a technical discussion is coming. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

For latest radar imagery, to check for watches and warnings, and for links to sites in the world of weather, feel free to click over to my website: www.mattnoyes.net

Matt's Weather Summary:  The next few days will bring lots of complexities - which means a few surprises may be in the offing.  But my advice as a meteorologist is for you to tune in frequently to our updates on NECN, as we are always reviewing the latest information and revising our forecast as necessary, and track the heaviest rain on your own with radar imagery, available from my website, www.mattnoyes.net.  The trend thus far has been for rain to move north and east slower than originally anticipated...but the heavy rainbands continue to drift across New England.

A wave of low pressure that developed off the New Jersey coastline yesterday brought flooding rains to the Big Apple and brought wind gusts to 56 miles per hour with moderate coastal flooding to Southern New Jersey Wednesday afternoon.  Now we watch this rain band shifting northward with embedded waves of low pressure within it, and a tap to tropical moisture that trails all the way across Bermuda and into the Leeward Islands in the Tropical Atlantic!  The supply of copious moisture will continue to feed our rainbands, ensuring that flooding rains will occur in at least some communities under the center of the slow-moving band.

The slower movement of the rainband has delayed flooding threats by about 12-18 hours.  Therefore, the few inches of rain with a flooding threat discussed yesterday for Western MA and Connecticut will now occur during the day Thursday and into Thursday evening while the remainder of New England finds non-flooding rainbands gradually expanding north and east, encompassing most of Massachusetts, Connecticut, Rhode Island, Vermont and New Hampshire by Thursday evening.  Western NH and Central MA will come under the gun for possible flooding late Thursday Night through Friday, and areas farther east may see some flooding Friday through Friday night.  This storm has been a tricky one, and understand that the farther out in time we go, the less certain we can be about the forecasts.  So, I encourage preparation but monitoring of my forecast updates for details.

It's also important to understand significant flooding is often localized - thinking back to this past weekend, the number of communities seriously affected by flooding were limited relative to the number of towns and cities in New England, but it's so important that we're all prepared - from rural communities to major cities - in case flooding should affect our particular town.

Meanwhile, as New England remains sandwiched between high pressure over Southeastern Canada and waves of low pressure to our south, the stiff northeast winds will continue, though perhaps not quite as intense as Wednesday's winds with gusts over 25 mph inland, and still over 35 mph at times along the coastlines of Southern New Enlgand.  Closer to the center of high pressure - those of us in Central and Northern Maine - will see some sun through the clouds today!

By Friday, the slow-moving rainband will continue to move northeast and likely will move into much of Eastern New Enlgand.  A strenthening center of low pressure to our south will move closer to New England and we'll be carefully watching the potential for increase winds and waves along our east-facing coastlines, where beach erosion will occur, coastal flooding is possible later Friday evening, and winds may gust high enough for scattered power outages.  This coastal threat is still highly uncertain, though, so please do check back.

Some threats to keep in mind with this event through Saturday morning include: 

Widespread:  Basement flooding (pick up valuables off the basement floor just in case), hydroplaning (leave extra time to travel once the rain moves in), slick roads with leaves and pine needles combined with water (use caution!).

Scattered:  Street flooding (clean out drains and catch-basins today if you haven't done so already), High streams and rivers that may flood yards (be prepared to seek higher ground if you're near a stream or river), road washouts (NEVER drive across flooded roadways - impossible to know the structural integrity of the road beneath you), swollen rivers place greater strain on boat docks and marinas (either secure the docks or pull them out in high risk areas outlined above).

Isolated:  Bridge washouts and collapses, coastal flooding and beach erosion.

I'm hopeful that if showers are lingering on Saturday morning, the rain will ease and give way to breaks of sunshine by late morning through most of New Enlgand.  In Maine, however, rains and wind will continue heavy at times into the afternoon.  By Sunday, a storm center embedded in these rainbands will be located east of New England, but will strengthen dramatically.  This will mean gusty winds for all of New England on Sunday with gusts over 35 mph in some communities.  Southern New England will find a blend of clouds and sun with a few showers popping up during the afternoon, while Northern New England will find mostly cloudy skies and scattered showers throughout the day.

Monday is looking like a brighter day!

Technical Discussion:  See Below.

Matt

Matt's Technical Meteorological Discussion:  Updated Thursday, October 13 at 11:50 AM

The trend of S-L-O-W continues with the progression of this rainband.  The NYC flooding occurred 12 hours behind my schedule, and now our New Eng flooding likely to run about the same.  I know the operational models are all over the place and that makes this difficult.  The NAM has shown it's superior handling of the boundary layer owing to its higher resolution, but is overdoing it with today's setup, as isentropic lift owing to warm and moist advection aloft has already overwhelmed the dry boundary layer with rain falling much farther north and east than the NAM progged.  That's good news for my forecast, but not such good news for flood-vulnerable areas.

First off, let's get a good handle of what's going on.  Northeast surface winds prevail through most of NewEng - though not all.  Interesting to note as of 13Z, the 45 knot Mt. Washington summit SE wind is mixing down and various locations in Vermont have come around...evidence of differential advection occurring in the lowest levels of the atmosphere in those locales that are still northeast.  Also interesting to note rise in temps on Cape Cod as warmer airmass appears to be advecting in off the ocean.

Perhaps one of the most important features on the weather map are the multiple mesoscale low pressure structures that continue to spread westward off of the Atlantic.  Yesterday, one of these mesoscale lows - energized by some of the low-level vorticity that was once Subtropical Depression 22 - moved westward into Southern/Central NJ.  I was alerted by Dan Skeldon, a meteorologist for NBC40 in Atlantic City, of the wind gusts to 56 mph at the immediate shoreline and minor to moderate coastal flooding that occurred with the passage of this mesolow.  As of this writing, another of these mesoscale low pressure centers is barrelling westward toward KBLM (Belmar, NJ) and winds are gusting to 33 knots from the NE in advance of this wave.  Another wave is already evident well S of Nantucket, and this one likely will come across Long Island later this afternoon.  I'm sure there are tons of these mesolows embedded in the flow of moisture, as this nearly always is the case when advecting tropical moisture over a shallow cold dome, and clusters of deep convection evident on IR satellite imagery this morning are evidence of this trend.  The reason I say these mesolows are so important is because they are governing both the heaviest rainfall and the strongest winds.  Winds are clustered relatively close to the well-defined centers on radar imagery, and heavy rains are found on the northern and western side of the circulation, as well as spreading far north of the centers owing to enhanced warm advection on the north side.  These bands of enhanced lift have been spreading north into NewEng and are responsible for the bursts of heavier rain that have been moving in.

As for the "wave train," so to speak, it's clearly been shifting northward over the last 18 hours and that trend should continue, meaning the axis of heaviest rain will continue to gradually shift north and east...but this will be a very slow process with ridging slow to let go over eastern and northern areas, where the sun will shine thru clouds in Northern ME again today.

A crucial 12 hours lay ahead beginning now.  The NAM's forecast has been so far west with the rain band because it's allowing the well-defined low west of Bermuda to wrap up the moisture train from the Tropics and redirect it westward, where it interacts with incoming Northern Stream energy, and the old NGM agrees with this solution.  The GFS/GGEM/regional GEM are the farthest east with the progression of the rainband, and the NOGAPS/ECMWF/Canadian Ensembles find a middle ground, keeping heavy precip across Western areas before swinging it thru VT/NH/ME Fri Ngt into Sat.  While the next 12 hours will give us an excellent idea as to what solution plays out, right now it appears on VIS/IR/WV imagery that there is certainly a well-defined low level circulation, and the mid-level center has indeed been tapping into the tropical moisture feed, but is simply not large enough in diameter to pull in the entire feed of moisture.  Additionally, I have problems with agreeing with a solution that places the heaviest rain band over NY State thru the entire period - while the sfc and low level flow there will be strongly divergent at the intersection between cyclonic and anticyclonic flow...it makes more sense to at least have this band in Western NewEng if not farther east, where greater low-level convergence will be occurring.  Therefore, at this point I'm continuing to follow a solution that continues to gradually drift the rainband north and east over the next 48 hours.

Still, rain has been filling in on the western periphery of the ridging up the Hudson Valley and thru most of Western New England.  Even this morning's burst of rain brought 1" per hour rains to the orographically favored areas around Route 7 in Berkshire County, and northward into Bennington County, VT.  These areas only have 6-hour Flash Flood Guidance of about 2.5" and I have to believe we're going to exceed these values in these areas...as well as Windham County, VT...by the end of the day.  Additionally, flood warnings have been up for Litchfield County, CT, and most of Northern CT is only looking at 3"/6 hr FFGs, so some of these communities likely to see flooding by the end of the day.  I've also included much of the remainder of Western MA in this area for a high risk of flooding thru Thu Ngt, as heavier rains should set up and FFG values aren't much higher.  Local topography will dictate communities hardest hit.

Fri we should see the rain continuing to shift NE and FFG values are 1.8-2.8" most of NH/ME.  Given the slow progression of the rainband, probably no problems in most of these areas until Fri Ngt and even Sat in ME, though SW/Wrn NH may see problems earlier - possibly as soon as Thu Ngt if the blossoming area of precip and cold clouds tops SE of Nantucket continues on it's current course through this evening into tonight, putting in through Central NewEng.

Then there's the coastal flood and wind factor.  This is a difficult parameter to nail down, but I'm still nervous about what I wrote of yesterday - historically it seems a persistent onshore flow for several days prior to a stronger blow sets us up for coastal flooding worse than what normal parameters would suggest.  The buoy E of BOS harbor is 10 ft every 10 sec as of 15Z, but buoy 44008 SE of ACK is 15 ft every 10 sec, 44025 S of Islip is 14/10sec, and then there's my favorite, buoy 44004 200 mi. E of Cape May NJ coming in with gusts to 47 knots and waves 21 ft every 12 sec.  OK, so maybe some of this is me just sharing meteorological numbers I think are impressive, but my point is that things get a lot rougher the closer you get to the wave train.  We've also seen the increased winds ahead of the mesoscale lows, and if one of these mesoscale waves cranks up prior to passage of the actual main surface wave...or if the surface wave is stronger on passage than currently projected...we have a problem along all of our east-facing shorelines.  In fact, even just taking the 00Z GFS prediction of 10m wind, winds would be 20-30 knots sustained from the E...and that's enough to keep me nervous about this for the Fri Eve high tide.  Obviously there's only so long we can wait on deciding to go off on this potential or let it pass, so I will continue acknowledging the potential for this on-air as I've been doing, but will wait to see if we can get some better model agreement of how the synoptic scenario will evolve before hitting harder.

Saturday rains fall heavily in Maine as the northern stream shortwave interacts with the tropical moisture and upward dynamic forcing is enhanced by this interaction.  The Central and Eastern areas of NewEng probably rain hard Fri Ngt into very early Sat AM but should taper to showers quickly as cyclonic vorticity advection and warm advection move east.  Winds will shift from NE to W and NW during this period, and depending on how it all shakes out, winds may not be very strong outside of Maine early on Saturday as the wave moves just east of NewEng, but will kick by late in the day as the wave deepens into the impressive low discussed here yesterday.  As this low deepens rapidly, winds will continue to roar into Sunday - tough to say just how strong without much guidance agreement on how any of this will evolve, but pressure gradient is strong and degree of cold advection will help to translate this momentum down to the surface.  Wind gusts over 35 mph seem like a no-brainer - could be much higher, esp in higher terrain (more like over 50) but I want to feel better about our forecasted synoptic solution actually verifying.

Now, remember that here at NECN we cover ALL of NewEng, which means up to the Canadian border.  This means we have to consider the possibility of snow on the backside of this system for those of you reading this discussion from the far Northern reaches of New England.  850 mb temps are forecasted by most operational models to dip below 0 C Sunday evening in the far northern reaches of VT, NH and ME.  In addition, winds are forecasted to blow strong out of the Northwest - an upslope direction for the mountains of the north.  At this point, 925 temps are progged by the GFS to be +1 to +2 C Sunday night into Monday morning, and precip continues to crank out along the Canadian border thru the period.  I would like to see a wealth of cool air at the surface to have me really concerned, and I'm not seeing that - in fact we have to go north of Hudson Bay just to find subfreezing temps this morning.  While dynamic cooling will likely bring 925 temps below 0, and mountain summits may find their first snow of the season in the far northern reaches of NewEng, there doesn't appear to be enough shallow cool air to warrant concern otherwise.

Another threat for snow comes especially for Northern Maine the middle of next week.  After a day between systems on Monday with sunshine and winds increasing ahead of a strong cold front that passes through on Tuesday with showers, cold air comes streaming in.  This air will be a shot of early-winter chill for some of us in the far northern reaches, and it will likely be deep enough to bring the surface below freezing Tuesday night.  There are indications that as the warm air comes surging back aloft on Wednesday, we may find a brief period of winter precip.  This is still very far out - and the GFS looks way too amplified with its Wednesday clipper compared to Ensemble members, but a few flakes isn't impossible, esp in Nrn ME.  We'll see.

On that note, best of luck with the tricky forecasting the next few days.

Matt

Flooding Rains Still Expected for Some Communities...Preparations Continue

Welcome to the weather blog! While the web address has changed, the blog will still be the same Monday through Friday discussion - with some improvements! Over the course of the next few weeks and months, you'll find me experimenting and adding new features. Maps, pictures, and other multimedia are enhancements I'm hoping to be able to make as I learn more about how to maximize the new site. Format will be similar to the old version - you'll find a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow. If no technical discussion is available when you check in during the morning, check back later as it often comes after the Weather Summary - I try to indicate at the end of the general weather summary when/if a technical discussion is coming. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

For latest radar imagery, to check for watches and warnings, and for links to sites in the world of weather, feel free to click over to my website: www.mattnoyes.net

Matt's Weather Summary:  Our complex weather pattern continues, and this means New Englanders will continue to stay on-guard for flooding - from interior to coastline - over the next few days.  Meanwhile, enough dry air has surged southward from Canada that we're seeing sunshine for our Wednesday from Northern Vermont and New Hampshire, to Central and Northern Maine.  No such luck for the rest of us, though - rain, heavy at times, will fall periodically with localized flooding possible until Saturday morning, and river flooding possible beyond that.

The next few days will bring lots of complexities - which means a few surprises may be in the offing.  But my advice as a meteorologist is for you to tune in frequently to our updates on NECN, as we will constantly (as always) be reviewing the latest information and revising our forecast as necessary, and track the heaviest rain on your own with radar imagery, available from my website, www.mattnoyes.net.  That being said, it doesn't appear right now as though we need to change much in the forecast...so far things look to be on track.  Here's how it looks as though it will play out:

A storm center that was once numbered "Subtropical Depression 22" over the Atlantic has merged with new moisture and energy, nearly stalling south of New England this Wednesday morning.  This low pressure center has been focusing a strong inflow of moisture into Long Island, New York City and New Jersey last night and this morning, and urban flooding has been occurring in parts of The Big Apple today.  Closer to home, Tuesday night rains have pushed westward and much of New England will find a morning and early afternoon break in the action - with light rain and a few heavier downpours, but no flooding rain.  Most of Wednesday - though moist - will still be a good time to prepare for possible flooding in your community.

The overall pattern of the next 24 hours will be for a northwest to southeast oriented band of heavy rainfall - located over New York and Southern Connecticut as of this writing Wednesday morning, to gradually shift toward the northeast, affecting most of New England over the next three days.  The exact communities that will be hardest hit by flooding are impossible to predict with accuracy, but I do believe we can narrow down who will be under the gun, and when.  First and foremost:  Please understand that significant flooding is often localized - thinking back to this past weekend, the number of communities seriously affected by flooding were limited relative to the number of towns and cities in New England, but it's so important that we're all prepared - from rural communities to major cities - in case flooding should affect our particular town.

Here's how I expect things to break down:  After several hours of a break in the action with just heavy drizzle and light rain to start the day Wednesday, steadier rains will spread northward off the Atlantic ocean later Wednesday.  These rains will fall heaviest Wednesday night, and greatest amounts will fall along the Eastern slopes of the Berkshires, the Litchfield Hills of Connecticut, and the lower Connecticut River Valley, where three to four inches of rain may fall by Thursday morning, which would be enough for some communities to sustain flooding.  Elsewhere in Southern New England, one to two inches of rain are more likely, which should not allow for significant flooding, though some small streams may come out of their banks.  At the same time, the stiff northeast winds will continue - so most of New England experiences a blustery day with coastal communities frequently gusting over 35 mph...strong enough winds at the immediate coast that a few lighter tree limbs may come down, and an isolated power outage is possible.  By Thursday, it's possible we see a break in the action again - though timing that out at this point is quite difficult.  Your safest bet is to plan on periods of rain Thursday into Thursday night, with our highest risk of new flooding during that 24 hour period shifting farther east across Central MA and the Metro West area west of Boston, Southern NH, Northeast CT and Northern RI.  By Friday, a strenthening center of low pressure to our south will move closer to New England and this will: 1) Shift the band of heaviest rains a bit farther north and east, and 2) Increase winds and waves along our east-facing coastlines, where beach erosion will occur, coastal flooding is possible and winds may gust high enough for scattered power outages.  I'm expecting the highest threat for new flooding Friday and Friday night to occur from Central Maine through much of New Hampshire and into the Boston Metropolitan area.

Some threats to keep in mind with this event include: 

Widespread:  Basement flooding (pick up valuables off the basement floor just in case), hydroplaning (leave extra time to travel once the rain moves in), slick roads with leaves and pine needles combined with water (use caution!).

Scattered:  Street flooding (clean out drains and catch-basins today if you haven't done so already), High streams and rivers that may flood yards (be prepared to seek higher ground if you're near a stream or river), road washouts (NEVER drive across flooded roadways - impossible to know the structural integrity of the road beneath you), swollen rivers place greater strain on boat docks and marinas (either secure the docks or pull them out in high risk areas outlined above).

Isolated:  Bridge washouts and collapses, coastal flooding and beach erosion.

I'm hopeful that if rain and wind are lingering on Saturday morning, the rain will ease through the day and should even give way to breaks of sunshine.  That being said, the winds will shift to the northwest and should still be quite gusty throughout the day.  Sunday also looks very windy, under a blend of clouds, some sun, and a few scattered showers.

Technical Discussion:  Out By Early Afternoon.

Matt

Matt's Technical Meteorological Discussion:  Updated Wednesday, October 12 at 2:00 PM

The rain was slow to move into NYC - flooding parts of Long Island and Central/Northern NJ but waiting to close in on NYC area until this AM, now street flooding ongoing.  So, if you're reading from that area and agreed with my thinking, then panicked with no rain last night, hopefully you're feeling redemption.  This rainband will continue to shift slowly northward as warm advection and associated isentropic lift gradually shifts north as well.  Net result will be for rain to fill-in thru areas of Southern NewEng where dry air has invaded, though the battle will take some time with Tds in the 40's advected all the way thru much of Srn NewEng.  Thanks to this dry air, slow progression of band will spare most Central and Eastern areas from flooding into later Thu, tho Western MA and CT will be under the gun tonight with combination of mid-level lift (H5 and H7 thermal gradient) and moist advection increasing thanks to increasing 500 mb jet cranking at 40-50 knots direct feed from Atlantic upper low, which is now effectively tapping copious amounts of tropical moisture from disturbance riding north of Puerto Rico.

The operational model solutions have been all over the place with the forecasts, and once again it's important to focus on the synoptics.  As mentioned yesterday, the low-level thermal gradient has shifted well south of New England, but the mid-level gradient remains nearby and will move overhead.  Additionally, a slow retreat of the Canadian high pressure will allow the low level baroclinic zone to gradually drift farther northward - or more accurately, to become a bit more diffuse with the northern edge relaxing and moving over us while the deep surface moisture stays farther south.  At 700 mb, Theta-E advection will move from Wrn NewEng late today and tonight...to Central parts of Southern NewEng Thursday and Thursday night, to Eastern NewEng Fri.  This will result in heaviest rainfall in Western MA and CT (possibly Southern VT on northern fringe) tonight, Thursday into Thursday night focuses on Boston's Metro West suburbs west to Springfield and extending north into Southern NH and south into most of CT northeast of Hartford, and Nrn RI.  By Friday, expecting heaviest rain Boston metro area thru most of NH and into Western ME and Southern ME coastline.  Flash flood guidance suggests White Mountains and most of ME can't take much water - 12 hour amounts of 1.8-2.75" will cause flash flooding - and I do expect most of these areas to meet or exceed these amounts Friday into Friday night - that's my reasoning for extending high threat of flash flooding into these areas at the end of the week.

In addition, there's still lots to work out with exactly how the low pressure wave south of Long Island this afternoon evolves.  The ECMWF/GGEM camp (I mention these two because they have been most consistent) really crank up the low later Friday - though 12Z run does not follow through with this in the GGEM and instead the NAM has jumped on board.  The GFS has kept a steady flow of moisture interaction between the ocean low discussed in previous discussions and the surface low south of NewEng, but doesn't hand off enough energy to really energize the wave as it moves by NewEng.  The problem I see with this solution is that the shortwave digging into the nation's midsection the next 36-48 hours seems to dig too deep and lower heights too much for the upper low not to be pulled westward.  However, I do think it's going to be a relatively slow process to completely hand this energy off, and therefore the likely scenario is for the wave south of NewEng to just be showing the effects as it moves by - entering a period of what will be rapid strengthening as it moves from just east of Cape Cod to Eastport, ME from Saturday morning to Saturday evening.  This deepening phase actually is important for a few reasons - 1) Keep in mind that a deepening storm is still increasing on just about all parameters, including inflow.  This adds further support to my concern of a flooding problem occurring in Northern NewEng - esp White Mountains thru Maine - after the period of flooding in Central and Southern NewEng...specifically this northern flooding event would be Fri night into Sat.  2) Winds will start to crank with this wave as the bottom drops out, as well.  It shouldn't be overlooked what an amazing wind event this is already - gusts to over 30 mph are extending as far inland as Western CT as of this writing, and most of that is thanks to the pressure gradient between the 1038 mb high north of the mouth of the St. Lawrence and the currently weak 1020 mb wave south of Long Island.  We shoud not underestimate the northeast wind potential late Friday into Saturday morning on the north side of what will then be a strengthening circulation, working with a high degree of baroclinicity.  Gusts over 50 mph aren't out of the question during this time period esp from Boston northward thru the Maine coastline.  Friday evening's high tide up and down the NewEng coast is an 9.5-10 foot tide between 9 and 10 PM, and Saturday morning's isn't quite as high.  Still, it seems there's enough potential here that I felt it wise to continue mentioning the potential for coastal flooding - beach erosion seems likely regardless with the pounding surf.  Setups like this...with a persistent easterly wind for several days prior to a stronger onshore blow...tend to bring coastal flooding worse than expected and worse than standard protocol would suggest.  Still, this will hinge on the final track of the intensifying wave, and whether we're right on the timing and degree of interaction with the Atlantic upper low.

Regardless of where and how quickly the storm takes off, as it bombs (eventually) winds will have shifted to the northwest and will crank...especially on Sunday...for a widespread windy day - the magnitude of which will be determined by the magnitude of cold advection that will assist in downward momentum transport.

That's all for today.

Matt

A Breather Tuesday...Periods of Flooding Rain to Return...Coastal Winds May Kick

Welcome to the weather blog! While the web address has changed, the blog will still be the same Monday through Friday discussion - with some improvements! Over the course of the next few weeks and months, you'll find me experimenting and adding new features. Maps, pictures, and other multimedia are enhancements I'm hoping to be able to make as I learn more about how to maximize the new site. Format will be similar to the old version - you'll find a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow. If no technical discussion is available when you check in during the morning, check back later as it often comes after the Weather Summary - I try to indicate at the end of the general weather summary when/if a technical discussion is coming. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

For latest radar imagery, to check for watches and warnings, and for links to sites in the world of weather, feel free to click over to my website: www.mattnoyes.net

Matt's Weather Summary:  Our complex weather pattern continues, and this means New Englanders will continue to stay on-guard for flooding - from interior to coastline - over the next few days.  We'll start with the good news, and that's the fact that we'll only find showers across New England today - perhaps some embedded heavier downpours from time to time, but no rains heavy enough to ignite new flooding.  This breather comes as cool and dry air from a strong Canadian to our north flexes its muscle and hold flooding rains to our south - though New York City and most of New Jersey could be in for quite a wet and wild afternoon and night late Tuesday.  So much dry air will surge southward from Canada, in fact, that Bangor, Maine, points northward will likely see some sunshine Tuesday afternoon.  No such luck for the rest of us, though - another grey day with periodic showers and areas of drizzle.

The next few days will bring lots of complexities - which means a few surprises may be in the offing.  But my advice as a meteorologist is for you to tune in frequently to our updates on NECN, as we will constantly (as always) be reviewing the latest information and revising our forecast as necessary.  That being said, it doesn't appear right now as though we need to change much in the forecast...so far things look to be on track.  Here's how it looks as though it will play out:

A storm center that was once numbered "Subtropical Depression 22" over the Atlantic if moving northward along the Eastern Seaboard today, south of New England.  This low pressure center will help to focus a strong inflow of moisture into New York City and New Jersey today into tonight, and significant street flooding will be possible in the Big Apple later today.  Closer to home, the South Coast of New England may be on the northern fringe of this rainfall with locally heavy rains falling tonight, but most of the rest of us will simply deal with clouds, drizzle, cool temperatures, and a few showers.  Overnight tonight, the dry air oozing south out of Canada will exert enough influence on the State of Maine to clear skies in Central and Northern Maine, allowing for temperatures to drop into the 30's!  Elsewhere, clouds hold tight and temperatures bottom out in the 40's to near 50.

Wednesday the area of rain to our south will gradually migrate northward.  While it may lose organization as it makes the move, the rain is expected to reorganize late Wednesday, and this may result in renewed flooding through parts of Central and Southern New England.  At the same time, winds will begin to crank out of the northeast at the coastline, with northeast winds exceeding 35 mph along the coasts of Southern New England.

This same general pattern is set to repeat through Saturday morning, though the rain and the wind may grow more intense as the week wears on.  The reason for this is the potential development of a large ocean storm - which will consist of energy over the Ohio Valley, tropical moisture streaming out of the Bahamas, a large energy center over the Atlantic, and significant thunderstorms over the tropical Atlantic which may even organize enough to develop into a named or numbered tropical system (would be named "Wilma").  All of these disturbances may converge for a very powerful ocean storm, and this would raise the concern for strong winds along our coastlines, as well as battering waves capable of beach erosion and coastal flooding later this week.  Keep in mind that lots of this will hinge on how all of these disturbances come together, and the exact path and intensity of the potential ocean storm.  Regardless, surges of potentially flooding rains will continue off and on until Saturday morning, when the powerful storm will likely pull away from New England, leaving behind a strong northwest wind and drying conditions for Sunday.

In the meantime, we can use this breather day to prepare.  Remember what we've seen first-hand in southwest New Hampshire this past weekend - flooding coverage can be localized, but consequences can be significant.  Good preparations to make at this stage of the game include:  cleaning out catch-basins and drains (leaves are clogging some of them), preparing for basement flooding (elevating valuables off the floor), city and town planners should be prepared for possible street flooding, washouts, or flooding of low-lying businesses and residences.  Again, this won't be something that every New England community will have to deal with over the next several days, but with several inches of rain to fall on some towns over the next few days, all communities should be prepared.

Have a good day!

Technical Discussion:  See below.

Matt

Matt's Technical Meteorological Discussion:  Updated Tuesday, October 11 at 6:55 PM

Evening Update:  I've reviewed the morning and afternoon model runs and believe our thinking looks good. I have to assume the NAM QPF is completely out to lunch beyond 18 to 24 hours - even the vorticity progs and synoptic pattern it forecasts just doesn't favor the thin band of precip far west being the only band for the next few days.  Nor do current conditions support it!  On the contrary, we are going to experience widespread midlevel warm and moist advection with a wind at 500 mb only becoming more favorable to transport moisture in from the Atlantic.  At this point, my suggestion to forecasters would be to throw away the technological portion of the guidance and utilize synoptics only.  Make the rainfall forecast based on these synoptic parameters and then check against a non-NAM model blend (esp GFS/GGEM) for a double-check.  I also think the GFS is too far out with the Atlantic low - there is going to have to be a formation of the low closer in to the coastline given the interaction that will take place with the eastward migrating upper low over the OH Valley, and this supports a position close enough for this thing to bomb and still give coastal NewEng a hearty blow later Fri, then wrap up and swing winds to the NW but perhaps menacingly strong in Maine around the backside of a deepening low that will go from hybrid (yes, I think with the amount of tropical moisture and warmth to become involved we may have a hybrid storm) to entirely extratropical.  Have a good night...previous discussion below.

********************

Forecasting in this pattern takes some guts, so if you're a forecaster who's feeling trepidation about the forecast, that's natural in a pattern like this - it's an opportunity to shine or to bust, but there are so many challenges along the way that few forecasters will nail it all, and those who stumble have the chance to get back up.

My personal stumble came with last night's rain - not a rain shield that developed but instead a persistent and stretched out band of forcing that appears to have established with the aid of a RRQ diffluent jet quadrant, coupled with a 700 mb front.  So, the amounts of 1-2" verified but in a much different areal configuration that I'd have expected.

Now we look ahead to what is yet to come and we see the merger of old STD22 with tropical moisture off the Atlantic seaboard.  These two factors will combine for a well-defined wave of low pressure that will crank up easterly flow in the low levels on the north side of the circulation, while high pressure nudges southward as best it can from southeastern Canada.  The results will be multifaceted - first, New York City and Northern New Jersey are under the gun for some extremely heavy rain.  We're only seeing the beginning of this rain taking shape over the waters south of New Eng and this should wrap westward into the NY Metro area and northern suburbs of NJ.  I don't know all of the intricacies of the NYC drainage system, but this amount of rain that I'm expecting - several inches overnight - should pose some serious street flooding concerns in the Big Apple and Northern NJ tonight.  If you're a meteorologist reading this, it's not too late for folks to get out this afternoon and clean out drains and catch-basins and would be worthwhile - and low-lying businesses and residences in flood prone areas should probably move some items up off the floor with this much water on the way.

Here in NewEng, northern border of rains likely will affect the South Coast - esp of CT and RI.  Could be up to an inch of rain in extreme Srn CT and some street flooding in New Haven and Bridgeport is possible, as well as some small streams/brooks coming out of their banks in Southern Fairfield County.  The rest of NewEng stays far enough removed that we see showers...and areas of rain spreading northward through CT and Wrn MA...and well as parts of RI late tonight and early Wed AM, but should avoid flood problems thru tonight.

Wed we'll watch the area of rain over NYC/extreme Srn NewEng shifting northward.  The NAM then focuses most of the rainfall well west of NewEng over NY State...the GFS paints a much farther east solution.  The truth for each event has been lying in a GFS-weighted middle thus far, and that will likely continue.  Baroclinic gradients should be the determining factor for heavy rains, as it has been all through this pattern.  But while we've been using the low-level gradient thus far (and it still applies through tomorrow morning) this gradient becomes more diffuse by later Wednesday through Friday.  This means we'll have less forcing in the low levels, but still nothing to laugh at with a 30-40 knot 925 mb jet that may take shape off the Atlantic.  Still, for widespread synoptic forcing, my course of action has been to follow the mid-level isentropic lift in this timeframe, and contrary to where the NAM QPF prog paints the heaviest precip, even using NAM thermodynamic structures still places heavy precip farther east, in CT and Wrn MA later Wednesday, then shifting on a NW to SE axis thru Central/Srn NewEng Thu.  By Fri...lots to work out with the developing ocean storm, but the upper and mid level flow is favorable to at least tap the Atlantic upper low for moisture and feed rainfall amounts.  The fact that this upper low is tapping into the tremendous tropical moisture streaming north from Puerto Rico is a major problem because this will boost precipitable waters much above normal, and whatever falls will likely be tremendously efficient with regard to rain production later Thu and again Fri.

This is like a bad tease, to stop here, I know...at least it is for me.  But TV time calls - off to a school visit.  If I can write more this evening I will.  In brief: Winds gust over 35 mph coastlines of Ern MA Wed thru Fri, then shift direction thru the weekend but still signficant, coastal flooding/beach erosion a possibility thru the rest of the week - probable by week's end eastern coastlines.

Gotta go for now.

Matt

Periods of Rain to Continue This Week - Significant Flooding May Emerge Again

Welcome to the weather blog! While the web address has changed, the blog will still be the same Monday through Friday discussion - with some improvements! Over the course of the next few weeks and months, you'll find me experimenting and adding new features. Maps, pictures, and other multimedia are enhancements I'm hoping to be able to make as I learn more about how to maximize the new site. Format will be similar to the old version - you'll find a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow. If no technical discussion is available when you check in during the morning, check back later as it often comes after the Weather Summary - I try to indicate at the end of the general weather summary when/if a technical discussion is coming. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

For latest radar imagery, to check for watches and warnings, and for links to sites in the world of weather, feel free to click over to my website: www.mattnoyes.net

Matt's Weather Summary:  Some tremendous flooding in Southwest New Hampshire this weekend has prompted the Governor of New Hampshire to declare a State of Emergency.  While minor flooding continues on some rivers across New England as of this writing, the biggest concern now is going to be dam breaks in the hardest hit areas of Southwest New Hampshire, Southern Vermont and Western Massachusetts.  Although the heaviest of the rain has fallen for now (more flooding rains will fall Wednesday night) in these areas, up to 11 inches of rain has put extraordinary pressure on dam walls, and residents of riverside communities with dams upstream should stay abreast of the situation and be ready to move to higher ground if flood warnings are issued.

For many other locales in New England, the weekend was soggy but not as dangerous.  The week ahead look equally drenching, as a tropical feed of moisture continues to pour into New England and produce several inches of rain over the next few days.  This tropical feed of moisture comes as New England is squeezed between three major weather players - 1) A cold Canadian high pressure cell to our north, 2) A tropical high pressure center to our southwest, over the Atlantic, and 3) A weak low pressure system to our west.  Keep in mind that air flows clockwise around high pressure, and counter-clockwise around low pressure.  The result is:  a northeast wind flow from the system in Canada, and a flow of south winds pumping up lots of moisture aloft, thanks to the funneling south flow between the low to our west and high to our east.  This also sets up a clash between airmasses - tropical and polar both clashing with lots of moisture in place - and this is a perfect setup for heavy rains.

The first round of rainfall spreads back into New England Monday afternoon from southeast to northwest as the moisture backs in off of the Atlantic Ocean.  You can follow the progression of the rain on radar imagery from my website, www.mattnoyes.net.  By afternoon, rain will be falling in most of Southern New England, and this evening will bring heavy rain to Boston, Worcester, Springfield, Hartford and Providence, as well as most of the remainder of Southern New England, south of the Massachusetts Turnpike.  In these areas, localized street flooding will be possible, especially in urban and poor drainage areas.  One to two inches of rain with locally higher amounts will be possible in these areas between Monday midday and Tuesday morning.  Steady rains won't be quite so heavy in Southern New Hampshire and Northern MA, where a half inch to one inch of rain will fall.  With the heaviest rain falling south of our hardest-hit areas from this weekend, widespread significant flooding is not likely with this event, though a few communities may still experience flooding - remember the rule: "Turn around, don't drown."  No driving across flooded roadways.

Rain will taper to showers over the course of the morning on Tuesday, then cloudy skies with scattered showers Tuesday afternoon as we catch our breath between shots of tropical moisture.  The northeast wind around the Canadian high pressure center continues, though, so everyone remains cool.  By Tuesday night, another shot of tropical moisture will collide with this cool air over the South Coast of New England, and rains will redevelop in far Southern New England.  For some of us, the Canadian high pressure will come close enough to bring a noticeable improvement in our weather - those of us in Maine and in Northern New England are likely to find some sunshine as drier air moves in.  For the rest of us, Wednesday will be yet another cool and gray day.  By Wednesday night, another swath of tropical moisture will stream northward, and heavy rains will redevelop.  This round of rain is likely to drop at least a few inches of rain onto already saturated ground and already high-running streams and rivers.  Therefore, the threat for more widespread flooding returns Wednesday night into Thursday morning.

Heavy rains taper early Thursday but clouds and showers persist through Friday, and another rain making disturbance may push through New England on Saturday, believe it or not!  The good news is that right now, Sunday it looks like we may finally see the sun across most of New England...keep your fingers crossed!

Technical Discussion:  Out by early afternoon.

Stay dry!

Matt

Matt's Technical Meteorological Discussion:  Updated Monday, October 10 at 2:05 PM

A perfect setup for heavy rain events remains in place, with a few additional twists thrown in that add a great deal of complexity to the setup.  First, an analysis:

At the surface, we find a cold Canadian surface high that I analyze at 1032 mb over the mouth of the St. Lawrence River at 14Z this AM.  A 1019 mb low is just SW of Nova Scotia with a trailing cold front that's becoming stationary over Georges Bank.  This stationary front runs parallel to the Eastern Seaboard southward to a 1010 mb low off Miami.  Meanwhile, on the bigger picture, the weak low continues to spin and gradually fill while cut off from the jet stream over teh OH Valley, snow is falling in the Rockies, and a well-defined circulation that used to be Sub-Tropical Depression 22 is moving steadily northwest toward the Eastern Seaboard with very little data beneath it.  Aloft, a tremendous pattern has unfolded.  The main band of Westerlies runs up into Canada and across Hudson Bay, though trough splitting over the Pacific Northwest has resulted from the Intermountain upper low, and this is keeping vort maxes dropping into that low - interesting to note that the Rocky Mountain snows are falling under heights of 5650-5700 gpm!  Meanwhile, 5940 gpm ridge is sitting off of New England, and our cold air also comes only in the low levels courtesy of the high to our north, with 500 mb heights running 5880 gpm for most areas with 500 mb temps of -6 to -8 C but surface temps topping out in the 50's.  Mt. Washington summit reports a SW wind and temps equivalent to surface reading through the rest of NewEng.

That current analysis is enough to confuse us before we even delve into the forecast details!  But the bottom line is this:  Southerly flow is strong and will stay strong up the Eastern Seaboard and into NewEng aloft between weakening upper low to our west, and strong Western Atlantic ridge to our east.  Satellite imagery confirms we're tapping directly out of the Bahamas with this flow, though the Gulf of Mexico is offering input, as well.  Meanwhile, we may have a bit of a problem embedded in this string of convection.  As of 16Z, deep convection is firing off the South Carolina coastline - radar presentation shows the convection trying to wrap around a developing center and visible satellite imagery shows deep convection firing rapidly over the past few hours around this center and circulation is apparent.  Great (introduce sacrastic sigh here).  So over to the buoys we go and sure enough, 41004 is 40 degrees gusting to 18 kts, 41002 is 160 degrees gusting to 18-22 kts and 41013 is 20 degrees gusting 20-25 kts.  As of this writing, QuikScat and SSM/I microwave imagery suggests no circulation exists.  Bottom line is that we need to monitor this potentially developing circulation - NAM actually does pick up on this and carry it northward parallel to the Mid-Atlantic coastline, then hooks it northeast and takes it south of New England.  That would make sense from a warm core system moving north, given that we in New England are under the influence of the Canadian high and the stationary frontal boundary for this wave to travel along is south of us.  Still, this would enhance the potential for heavy rainfall, especially in Southern New England.  More on this in a moment.

And the complexities don't stop there.  The circulation formerly known as Subtropical Depression 22 this weekend is moving steadily NW, while the parent upper low is located substantially farther SE but also moving toward the eastern seaboard.  QuikScat imagery suggests winds around 30 knots on the east side of former STD22.  The question and concern is what's going to happen with this circulation when it encounters the tropical feed of moisture off the East Coast.  At this point, it appears the system is beginning to shear as it encounters the southerly flow, and most of the operational models pick up on the low level vorticity maximum with this storm and sweep it north, then northeast passing southeast of NewEng while being absorbed into the tropical wave train and moving southeast of NewEng Tuesday night.  Given that we sit in cool air here in NewEng, given the shear it appears to be undergoing on satellite imagery, and given what we saw the last impressive low level swirl do (nothing but look pretty) I'm going to assume that this system passes through relatively innocuous, but rest assured I'll be watching the buoy reports ahead of this system as well as the satellite intensity estimates, and would recommend others do the same.

Most of the operational models are keying in on yet another circulation that may be even more important.  Currently, it's the large and growing area of thunderstorms east of Puerto Rico.  While there doesn't appear to be a surface circulation yet, there is a midlevel swirl and great agreement among the guidance on taking this system north as it wraps up the eastern circulation of the Atlantic upper low to its north.  This storm is likely to develop into a named creature as it moves northward.  By midweek an interaction begins between the Atlantic upper low...which stalls near Bermuda...the storm to be named...and the OH Valley low that becomes absorbed into this entire mess.  The result should be a late-week storm consisting of three vort maxes all of different airmass origin, and this mixing pot means the potential for a very nasty storm that will retrograde westward toward the coastline.  Throw in the Canadian high to our north, and the pressure gradient will mean a ripping wind for the Mid-Atlantic with very heavy rains found in areas of maximized low level convergence and baroclinicity.  Special concern will be from Southern New England southward to Southern NJ - especially from NYC to Southern NJ it's possible a period of extended wind, surf and rain will culminate with a powerful wind churned around the west side of this growing creature over the Atlantic.  Southern New Eng certainly may become involved in this late-week spectacle as well, dependent on how these three systems merge and interact.

All the while, our own weather in New Eng will be governed by bursts of tropical moisture clashing with cold air at the surface creating differential advection and therefore very heavy rains from time to time.  Monday afternoon and night's rainfall should continue to take shape (though looking paltry as of 16Z) and fill in through Southern NewEng for 1-2" S of the MA Turnpike with lesser amounts north.  We can handle this rain without widespread new flooding.  Of more concern is for NYC on Tuesday and then as this rain lifts north later Wednesday coupled with the circulation off the Carolinas for widespread flooding rains in Central/Southern NewEng later Wed/Wed ngt.

Out of time - that's all for today.

Matt

Periodic Heavy Rain This Weekend...and into Next Week...

Welcome to the weather blog! While the web address has changed, the blog will still be the same Monday through Friday discussion - with some improvements! Over the course of the next few weeks and months, you'll find me experimenting and adding new features. Maps, pictures, and other multimedia are enhancements I'm hoping to be able to make as I learn more about how to maximize the new site. Format will be similar to the old version - you'll find a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow. If no technical discussion is available when you check in during the morning, check back later as it often comes after the Weather Summary - I try to indicate at the end of the general weather summary when/if a technical discussion is coming. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

For latest radar imagery, to check for watches and warnings, and for links to sites in the world of weather, feel free to click over to my website: www.mattnoyes.net

Matt's Weather Summary:  Breaks of Friday morning sunshine in some communities will gradually give way to increasing and thickening clouds through the day, as a significant slug of moisture rides northward along the Eastern Seaboard, ahead of a cold front moving east from the Upper Great Lakes.  This moisture comes ahead of what was once Tropical Storm Tammy - chock full of heavy rains brought in from the flow of tropical moisture that had been established from the Bahamas to the U.S. East Coast earlier in the week.  As Tammy encountered the jet stream winds - the fast river of air high in the sky that steers our storm systems and acts as a thermostat for the atmosphere - blowing from south to north, her clouds and rainfall have been spreading north, as well.  At the same time Tammy's been trudging toward the Northeast, we've also been watching the powerful cold front that's been moving east toward New England, not only serving as a pathway for Tammy's moisture, but also separating the sticky air that's moved into New England from much colder air behind the front.  As this cold front and the tropical moisture meet in the Northeastern U.S., this will mean plenty of rain for many of us and a period of strong winds for some of us.

Isolated showers will gradually evolve to scattered showers Friday afternoon, then gradually transition to a steadier and heavier rain by Friday evening from west to east.  It should be raining steadily for the evening commute in Hartford, CT, Springfield, MA, and Burlington, VT, while the steady rain will move in closer to 7 PM in Worcester, MA, and Concord, NH, and around 8 PM in Boston, Portsmouth and Portland.  Rain will fall heavily at times through Friday night as a wave of low pressure develops along the slow moving cold front and moves directly through New England, then with the front sagging a bit farther south on Saturday and bringing cooler air into Northern New England, periods of rain, heavy at times, will continue in Central and Southern New England.  It's possible that areas in far Southern and Northern New England will be out of the rainband for much of the day (including the South Shore of New England and Cape Cod), so please check the latest radar imagery through the day at www.mattnoyes.net.  Rainfall amounts of 3 inches or more are possible from 8 PM Friday to 8 PM Saturday over Southern and Central Vermont, Western Massachusetts, Central New Hampshire, and Central and Southern Maine.  Amounts of 1 to 2 inches will be more common in Southern New England during this period.  Also on Saturday, as the remnants of Tropical Storm Tammy move through, winds will kick up over coastal waters and gale force winds are possible early Saturday, especially from Provincetown points southward.  Again, please reference my main website for coastal marine advisory maps.

Yet another wave of low pressure - a piece of the moisture-loaded storm south of the Florida panhandle - will move through New England Saturday night into Sunday morning, dropping another couple of inches of rain.  While only limited flooding problems, if any, are expected on Saturday, this additional shot of rain may push streams, brooks and small rivers out of their banks in parts of Western MA, Southwest and Central NH, and Vermont.  The rest of Sunday will feature a wind swinging around to the northeast ahead of high pressure building into Southern Canada, and this will keep very chilly air filtering into New England, with highs only in the 40's and 50's from north to south!

It looks like bouts with rain - heavy at times - and cool air with a persistent east and northeast wind will hold at least through the middle of next week - yuck!  But...we do need the rain to ease our low to moderate drought conditions, especially in Southern New England.

Enjoy your weekend - back at it again on Monday.

Technical Discussion:  Brief discussion out by early afternoon.

Matt

Matt's Technical Meteorological Discussion:  Updated Friday, October 7 at 10:20 AM

Everything looks on track from past two days' discussions, but let me touch up briefly here:  Most of today's rain falls across NY/PA.  Weak warm and moist advection responsible for isolated showers in NewEng today, then more substatial advection begins to shift east over Western NewEng this afternoon and rain shield follows suit.  Eastern NewEng to see rain developing later this evening.  Differences in operational QPF - NAM and GFS solutions quite different.  If you were to divide models into camps of similar solutions for this parameter, NAM is on it's own.  That being said, model synoptics are always most important and are in good agreement, NAM included, in the lower levels.  Low levels should have an important role in rainfall with this event given baroclinic zone approaching, and it looks like with southward sagging front, 925 mb and surface baroclinic zone both set up from Upstate/Ern NY to Wrn MA to Central/Srn VT to Central NH to Central/Srn ME overnight tonight and this will be the focus for heaviest precip where widespread 3"+ amounts and localized 5" amounts will fall.  Forcing less on Cape Cod/Islands and this has been discussed already this week - wouldn't be surprised to see amounts under an inch here, and perhaps even under half an inch from 00Z Sat to 00Z Sun.  Wave of low pressure passes thru early Sat and 925 mb wind on GFS up over 40 kts with passage on Srn side of wave - across Srn coastal waters.  Thoughts expressed earlier this week regarding water temps still apply and P'Town southward the most likely area to see gales with areas farther north perhaps limited in momentum transfer due to shallow inversion courtesy of cool ocean temps.  As for Saturday itself, I'm playing it as touch and go for areas in far southern/northern NewEng because most precip should be along frontal boundary and away from the gradient there may not be much going on for the day.  The low in the eastern Gulf breaks into pieces with one piece coming thru Sat ngt into Sun morning and this brings another shot of heavy rains - at least another couple of inches in baroclinically favored areas.  Greatest flood threat for NewEng this weekend likely to be in Berkshires and hilly terrain of NH/Srn VT where upslope flow will enhance amounts.

The longwave pattern suggests we're going to be dealing with disgusting weather for an extended time.  Confluent flow over Nova Scotia will lock in high pressure north and east of NewEng and that will keep an east and northeast flow into the region as long as that high stays put, as well as feed cool air advection our way.  At the same time, the ridge over the Western Atlantic will be holding strong, especially with anomalously warm sea surface temperatures over much of the Western Atlantic.  Significant energy digging into the Intermountain Region will keep a deep trough dug across the Central and Western US.  This trof will eject shortwaves east that will have access to Gulf moisture.  All of this occurs as the main upper level lows - the aforementioned one and the upper low left across the Upper Ohio Valley - are very slow to move east, as the Westerlies have shifted north across Canada and left them behind.  In fact, from the perspective of 500 mb heights, were it not for these two lows, the entire US would be in a much above normal height pattern with the Westerlies so far north.  Instead, split flow on the West Coast allows shortwaves to drop into the Intermountain low, as it in turn ejects shortwaves east.  The upper low over Ohio should serve as a sink for some of these shortwaves, but will also eject and pinwheel shortwaves under its belly, wtih open access to the moist feed on the west side of the Western Atlantic ridge.  This will set up multiple shots through Thursday 10/13 of warm advection at 850 while surface cold advection continues.  This should spell additional rain events.

Have a good weekend.

Matt

Stubborn Clouds for Some...Sun for Others...Rain This Weekend...

Welcome to the weather blog! While the web address has changed, the blog will still be the same Monday through Friday discussion - with some improvements! Over the course of the next few weeks and months, you'll find me experimenting and adding new features. Maps, pictures, and other multimedia are enhancements I'm hoping to be able to make as I learn more about how to maximize the new site. Format will be similar to the old version - you'll find a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow. If no technical discussion is available when you check in during the morning, check back later as it often comes after the Weather Summary - I try to indicate at the end of the general weather summary when/if a technical discussion is coming. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

For latest radar imagery, to check for watches and warnings, and for links to sites in the world of weather, feel free to click over to my website: www.mattnoyes.net

Matt's Weather Summary:  A weak area of low pressure just a few thousand feet off of the surface was moving across New England Thursday morning.  This resulted in a few showers on Nantucket overnight Wednesday night, and may result in a prolonged period of clouds for Southeastern Massachusetts during the day on Thursday - for areas from Plymouth to Providence to New London points south and east.  Also subject to lots of clouds today will be the coastline of Maine, where a warm wind over cool water will keep clouds and areas of fog locked in through the day, holding high temperatures only in the 60's, while the rest of New England will see sunshine breaking through the clouds and temperatures climbing well into the 70's.

Fog will fill back in Thursday night, though probably not quite as dense as winds will be a bit more active from the southwest, but clouds will fill back in for just about everyone ahead of significant tropical moisture streaming northward.  This moisture comes ahead of Tropical Storm Tammy - weakening over interior Georgia as of this writing - chock full of heavy rains brought in from the flow of tropical moisture we've been watching in the Bahamas.  As Tammy encounters a wind blowing from south to north, her clouds and rainfall will spread north, as well, and Friday will be a mostly cloudy day for all of New England.  At the same time Tammy trudges toward the Northeast (how's that for alliteration?!), the powerful cold front that's been located in the nation's midsection picks up speed as it heads east.  The cold front and the tropical moisture meet right over New England, and this will mean plenty of rain, and a period of strong winds for some of us.

Rains are expected to begin as showers Friday afternoon, then gradually transition to a steadier and heavier rain by Friday evening.  Rain will continue heavy at times through Friday night as a wave of low pressure develops along the slow moving cold front and moves directly through New England.  This low pressure center will crank winds up out ahead of it - with gale force wind gusts possible south of Provincetown on our coastal waters Friday night.  By Saturday, a series of additional low pressure waves will ripple toward New England, and periodic heavy rain will continue through the day - raining heavily at times, and barely at all at others.  Another round of widespread heavy rain is likely Saturday night before our cold front nudges far enough east to taper rain to showers on Sunday.  That being said, the front won't be far offshore, and we do need to carefully watch this scenario to ensure rains don't back into New England on the ocean on Sunday, but right now it looks like breezy, cool, cloudy conditions will prevail with scattered showers from time to time.  And in this case, "cool" represents the coolest air of the season - the same air that helped to deliver 10-16" of snow in North Dakota yesterday for an early season record snowfall, will be spreading east in modified form.  Highs on Saturday are likely to be in the 50's across the North Country and 60's in Southern New England, but we'll all be on the cool side of the front, and therefore all in the 50's (40's in the higher terrain of the north) Sunday afternoon.

Clouds and periods of rain are with us on Monday, as highs hold in the 50's, and much of next week looks rather cool and unsettled, with a steady east to northeast flow of wind at the surface, and waves of moisture to contend with.

Technical Discussion:  See below.

Have a wonderful Thursday.

Matt

Matt's Technical Meteorological Discussion:  Updated Thursday, October 6 at 1:00 PM

Amazing little circulation discussed yesterday moved directly across Cape Cod early Thursday morning.  As the circulation neared, passing over the buoy south of Montauk and then over Eastern Long Island and toward the Cape, it became quite apparent there were no surface wind perturbations with the feature - this was discerned last evening as the circulation passed over it's first buoy  directly in the path and didn't produce more than a 3 foot sea and 12 knot wind.  Wind direction at buoys indicated a weak surface circulation was present but land observing sites were relatively unaffected.  My assumption is the circulation was not only shallow with regard to it's top, but also it's bottom - that is to say, above a possible inversion over the ocean, and below the cap above it, and Chatham 12Z balloon sounding did show increased winds either side of 900 mb.  Truly a remarkable feature, and has had some effect on sensible weather today - a few very light showers on the Cape, clouds held in longer in SE MA and RI thanks to the additional moisture input, and thrust of moisture evident by thicker band of clouds heading for Maine coast to keep clouds and fog locked in all day there.  South coast of NewEng under a boundary evident on satellite imagery - and this boundary is the leading edge to deeper tropical moisture and along an 850 mb Theta-E gradient with warm and moist advection along the boundary setting up the possibility of showers along the South Coast today.

The synoptic evolution for the weekend hasn't changed much from yesterday's very long-winded take on how things will evolve.  A quick summary of what was discussed yesterday (feel free to access yesterday's discussion in the archives) includes: 1) Clouds thicken tonight into early Friday well ahead of main slug of moisture, 2) Tammy attaches to front and serves as wave of low pressure, 3) Baroclinic zone allows wave to maintain and perhaps improve integrity as it moves NNE, 4) Burst of gale force wind ahead of wave likely Friday night under 60-70 mph 850 mb jet only where water is warm enough to prevent inversion - that is, Provincetown southward over the coastal waters - mainly a threat for mariners, 5) Heavy bursts of rain come through with most significant warm and moist advection ahead of waves - first Friday night (showers start Fri afternoon, steady rains move in from W to E Fri eve), then a band of S-shaped frontal precip a la 00Z NAM (though not 12Z) and the new 12Z GFS solutions Saturday along wavy frontal boundary, then another burst Saturday night with passage of another wave associated with strung out upper level energy ejecting ahead of main upper low which hangs west.

Interesting to note that, as discussed a few days ago, this may leave Cape Cod with less precip than other areas, and of course the Cape could use rain more than most.  But, as has been evidenced by the lack of fog the past few days on the Cape relative to the rest of NewEng, the airmass over the Cape is modified warmth from the warmer ocean waters as compared to the rest of NewEng.  Additionally, it looks like the front stalls west of the Cape, and this means significant warm and moist advection - necessary for heavy precip - will stay farther North and West.  Everyone should get into a slug of precip, though, later Saturday as everything shifts east.

Sunday still looks cool and breezy with leftover showers, but this forecast is based on advection of a very shallow cool airmass.  Differential advection will be ongoing as warm advection actually begins again on Sunday at 850 mb with Atlantic ridge holding strong.  This means we have to be ready for at least plenty of showers Sunday through much of NewEng.

The same general longwave pattern holds for the first half of the week, which means a persistent surface flow off the ocean with long fetch feeding in plenty of moisture, high to the northeast pumping down cold surface air, but bursts of warm advection aloft meaning bursts of rain through the first half of the week.

More on the longwave pattern and extended implications coming tomorrow...

Matt

Circulation South of New England...Tammy Develops Off East Coast...Weekend Gale En Route for Some

Welcome to the weather blog! While the web address has changed, the blog will still be the same Monday through Friday discussion - with some improvements! Over the course of the next few weeks and months, you'll find me experimenting and adding new features. Maps, pictures, and other multimedia are enhancements I'm hoping to be able to make as I learn more about how to maximize the new site. Format will be similar to the old version - you'll find a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow. If no technical discussion is available when you check in during the morning, check back later as it often comes after the Weather Summary - I try to indicate at the end of the general weather summary when/if a technical discussion is coming. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

For latest radar imagery, to check for watches and warnings, and for links to sites in the world of weather, feel free to click over to my website: www.mattnoyes.net

Matt's Weather Summary: Good Wednesday morning!  A later post than normal today since I'm off, but only for a day and there's too much going on in the weather to ignore it in the middle of my work week, even if I'm not on the TV this morning.  First news is that you're going to start hearing more about our newest named storm in Atlantic Ocean, Tammy.  The abundant tropical moisture I've been commenting on over the Bahamas and off the Southeast US coast the past several days has seen the development of a surface low pressure center, and early Wednesday morning, this center developed winds of greater than 39 mph and was named Tropical Storm Tammy.  It's important to note that this *hasn't* changed the forecast for the end of the week and weekend.  As you know, I've been watching the threat for a heavy rain and potentially strong wind event late Friday into Saturday, and this hasn't changed, but there are other fish to fry (so to speak) before we get there.

So let's start at the beginning.  High pressure anchored off the New England coastline fed a light wind flow off the ocean into New England last night.  This moist low-level flow allowed for dense fog and low-altitude clouds to redevelop, and like the last few days, this will take some time to burn off.  But also like the last few days, most of us will see sunshine emerging during the morning - the last of us not seeing the sun breaking through until afternoon in a few New England communities, but all of us rounding out the afternoon with sunshine and highs near 80.

Wednesday night will be similar to the past few nights, with fog and low altitude clouds filling in.  Meanwhile, an important feature in our weather is located south of New England - an area of showers and thunderstorms organizing around a well-defined surface circulation south of Block Island by a couple of hundred miles.  This area of low pressure is very shallow, and as a result, our guidance is having a hard time picking up on it, let alone making a forecast of it's intensity and path.  At this point, my thinking is that this circulation will migrate slowly northeast during the day Thursday, keeping the clouds locked in all day on Cape Cod and the Islands with tropical downpours possible.  It's possible that a tight core of winds will exists under this circulation, and winds may become gusty on the Cape and Islands during the afternoon.  The remainder of New England will be transitioning to a more tropical-feeling airmass with a sticky feel, more clouds than sun and the chance of a scattered shower here and there.

A strong cold front well to the west of New England will move close to us Friday, at the same time the deep tropical moisture over the Bahamas streams northward, including the remnants of Tropical Storm Tammy, who should make landfall close to the Georgia/Florida state border and then will be absorbed into the approaching cold front.  The result will be cloudy skies through Friday, with rain developing during the afternoon and evening from south to north.  A wave of low pressure is likely to ripple along this cold front, and gale force winds are possible on the coastal waters of Southern New England Friday night into Saturday morning, especially from Plymouth southward, with seas offshore building over 10 feet.  Mariners should consider staying in port Friday night into Saturday morning.  The rest of us should plan on a shot of heavy rain Friday night into early Saturday morning, with gusty winds possible along the coastal plain of Southern New England.

The rest of the weekend should feature this storm winding up northeast of New England, with much cooler air wrapping in behind it.  It's possible that rains will linger through much of the day Saturday - a lot of that will depend on how much energy is left to our south.  The most fortunate solution for us would be to have the rain kick out Saturday morning...and this is something that will become more clear in the Thursday forecast.  Regardless, temperatures will only be in the 50's for most areas both weekend days, and Sunday looks drier - though perhaps still plenty of clouds around with just afternoon breaks of sun, and an active cool breeze.

Technical Discussion: See below.

Enjoy your Wednesday.

Matt

Matt's Technical Meteorological Discussion:  Updated Wednesday, October 5 at 1:00 PM

Took the day off from work today to recoup after last night's U2 concert in Boston - what a show!  Still wanted to post here, though, given it's only one day off in the middle of a very active weather week.

There are a series of elements to watch here - Tammy developed off the Florida coast early this morning, take a look at a NewEng visible satellite and you'll see the well defined circulation immediately to our south, and of course the powerful cold front and associated waves for the weekend which are still a major headache.

Let's start close and work out farther.  Fog was on top of us this morning and is slow to burn off as per the usual these last few days.  After a repeat of sunshine and temps near 80 most areas excepting the coast of Maine, fog fills back in tonight.

But a huge headache is just south of NewEng - a couple of hundred miles south of Block Island.  I've been commenting on this thing for a few days, but now the time of real headache with this system is upon us.  While all eyes are on the Southeastern US coastline as well as the front well to our west, this feature can be easily overlooked - not only because it's small in nature, but also because NONE of the computer model guidance have a good hold on this circulation, including higher resolution MM5 models, largely because even these higher resolution models use the regional and global models to initialize.  There is very little cold cloud tops with this circulation today - evident by the lack of signature on IR satellite, showing only the deeper convection east of the circulation - but visible satellite imagery shows a well-defined circulation center.  The NAM does initialize a warm pool of air in the mid-levels, which it's done for the past few days - and this IS a warm core system.  Lack of convective instability appears to be the reason for lack of deeper convection, and while the nearest buoy...about 100 miles SE of the center...indicates SSE winds verifying the surface circulation, winds are only 6-10 knots as of this writing.  I have two concerns with this feature:  1) The effect of the feature on sensible weather through much of Eastern Southern New England on Thursday, 2) the potential for a low level wind core tightly wound around the center of circulation with a core of gusts 30 knots or greater.  My problem as a forecaster is that I have no data to back up this suspicion with no observations under the center, and with no computer guidance recognizing this entity, it is literally only instinct based on visible satellite appearance I have to go on.  An additional forecasting headache here is that even if there is a core of stronger winds tightly wound to the center, it's probably only 30-50 miles in diameter.  This really raises the stakes, because first we have to figure out if our assumption may be correct, then we have to accurately predict the track of the center of this disturbance.

First off, the center of this disturbance as of 16Z is located near 39.5N/72.0W and moving North at about 4 mph, obtained via visible satellite analysis.  QuikScat imagery indicates winds 15-25 knots in the center of the circulation.  The circulation is finding refuge in an extremely low shear pocket south of New England - less than 10 knots - and steering flow from 850-700 mb is due south to north but extremely weak.  With the ridge forecasted to hold east of NewEng tonight and tomorrow, and the trough slow to approach from the west, this general steering flow is likely to be maintained though perhaps come around slightly more NNE, with a possible slight increase in strength.  If the current speed were to hold, this would bring the disturbance into the South Coast of New England sometime Thursday afternoon or evening.  A low layer stratus deck was also observed on visible satellite imagery this morning extending NE from this circulation...effectively on the dividing line between the deeper tropical airmass just south of NewEng from the airmass over the 6-state region (buoy obs south of NewEng shows 70+ dewpoints).  The buoy observations reveal one other important point - water temps where this circulation is are currently running about 77-78 F, even though Eastern MA waters have cooled into the 50's.  This tight sea surface temp gradient will become important for Friday night's event, as well, but in the meantime, this is warm enough that I still think we need to watch the circulation - bands of convection have been trying to develop around it, but again, lack of convective instability and water temps about 1-2 degrees too cool may inhibit deep convective development - it's more the surface circulation I'm focused on.  Bottom line of all this is to bring this circulation north-northeast toward Cape Cod and the Islands on Thursday.  The associated warm and moist advectively induced stratus band should hold all day in these areas in advance of the circulation.  Showers and downpours will be possible in these areas, too, and without any guidance one way or the other, seems best to maintain what we think we know of the system through satellite approximation - 25 knot winds that will be possible on the Cape.  Of course, if I can get better satellite estimates, or ideally real obs from under this thing, I can raise or lower that as appropriate.  The effects of this system on Western New England will likely be minimal, but we also need to acknowledge the advection of 65-72 dewpoints ahead of the system over 55-60 degree water along the Eastern MA coastline north of Plymouth, and this may hold low clouds if not fog in most of the day from *somewhere* on the Eastern MA coastline points south along the coast - again, we're guessing without guidance, but one would think water temp and synoptic low level advection will be important components here, so perhaps from Boston southeast would be subject to this.

Rest of NewEng turns decidedly more sticky Thursday with lots of clouds as tropical airmass moves into midlvls and provides breaks of sun through the day, along with the possibility of a few afternoon showers popping up in Southern NewEng with moisture packed atmosphere and (admittedly seasonally weak) diurnal heating.

Cold front moves into Upstate NY and Western NewEng Friday, and we turn our attention to Tammy.  It's important to note that Tammy - in my opinion - doesn't change our forecast much at all, though there will be some changes that have to be acknowledged.  What doesn't change is that this moisture still will be absorbed into the front, form a frontal wave, soak NewEng and give us a period of gusty winds (probably...more on that in a moment).  Of course, it means media meteorologists like myself will have to say "here come the remnants of Tammy" but it's a matter of changing words from my previous statements of "here comes a ton of tropical moisture".  But we DO have to acknowledge that once we have surface circulation development, the system ramps up much quicker and easier.  The result of Tammy developing a circulation is a TON of latent heat release that wouldn't have been there before - at least not consolidated around the deep convection.  This *will* change the evolution of the pattern somewhat - infusing more available energy and moisture for rain production, and strengthening the tropical characteristics with the disturbed weather.  This should slow the front (though you'll remember that you and I were expecting this in previous discussions because we saw how much tropical moisture was there) and result in a more formidable wave rippling north along the frontal boundary.  I know the trend has been slower and slower with the rain on Friday from the guidance, but low level vorticity progs take the circulation and energy with Tammy NE pretty quickly, and I don't see too much reason to argue with that - it's likely she comes into Georgia/Florida state line or perhaps even further north into the climatologically challenged landfalling location of the Georgia coastline overnight tonight - then she should begin to interact with the approaching deep trough.  This will turn Tammy NE and accelerate her, and after weakening associated with landfall, she may actually begin to strengthen again as baroclinic effects take over.  Tammy's remnants have the potential to grow stronger that her current tropical self, at least with regard to surface winds and rain production - as she's only a 1004 mb circulation as of this writing.  One tough part of this forecast, as you've read in previous discussions, is the exact location of the cold front this tropical moisture will attach itself to, no only for placement of the heaviest rain, but also for understanding where and if strong winds will develop.  With the front stalling over NewEng and with no strong high close enough to our east to provide strong pressure gradient, the driving force of wind ahead of the wave of low pressure will have to be low-level jet.  GFS picks up on this well and develops 60-80 kt 850 mb jet over Cape Cod east of the low pressure center.  Next challenge with the wind forecast is the sea surface temp gradient discussed earlier.  Where SST's are cool, it's going to be tough to mix all the way down with these winds - so for now, I'd say gale force winds of 34+ knots should be confined to areas from Provincetown southward, but seas may build to over 10 feet and mariners should avoid the South Coastal waters Friday night into Saturday morning.  These gusty winds are likely to spread onto land over Cape Cod and the South Coast of New England - at least east of New London, CT - as well.

Things are still tricky for the rest of the weekend, largely focused on just how much energy is left over the SE US to come northward, and how quickly the front can come through after Friday Night/Saturday morning's wave.  There is becoming increasing agreement among some of the guidance on bringing another batch of significant rains through later Saturday.  I can certainly see this as a possibility with enhanced latent heat release ahead of the front slowing its progression and thereby allowing areas of rain to linger in Eastern NewEng through Saturday afternoon, while Western NewEng dries out a bit, excepting the Green Mountains where upslope flow keeps showers going.  If this solution verifies, Eastern NewEng would be able to get into the 60's Sat, while western areas hang closer to 50.  By Sunday, the cool air is in for everyone, though I'm still concerned about the winds coming around to the northeast ahead of the building area of high pressure, keeping clouds locked in for most areas, at least until late in the afternoon, with temps holding in the 50's.

Plenty to watch the next few days!  "Back to work" tomorrow...

Matt