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WARM AIR MOVES IN TODAY, MILD WITH POSSIBLE THUNDER ON TUESDAY

Snow marked the leading edge of warm and moist air surging in for many communities in Central and Northern New England - and parts of Southern New England, too - but this happened with a southerly wind which means it's not long to last in the most Central and Southern areas.  Nonetheless, reports of a solid coating to an inch are coming back from especially elevated inland terrain.  Warm advection continues on a southerly wind overnight as dewpoints rise and temp is forced upward overnight will result in areas of fog that will be most dense along the South Coast.  Fog and low clouds will start the day Tuesday but a pocket of drier air from 800 mb upward comes thru midday onward and should induce breaks in the overcast, esp with the assistance of downsloping flow.  With such a mild air in place - producing highs in the 50s and 60s today under plenty of clouds to our south and west - it should be easy to break 60 where the sun emerges and widespread 50s are anticipated elsewhere.  Convective available potential energy (CAPE) climbs to over 250 J/kg in Western New England in advance of the vorticity maximum that will fire a line of convection to our west that should carry into New England during the afternoon and evening.  These prefrontal storms should come in two rounds - and I'm uncertain of which one will have the best focus.  The first is with a mid-level shortwave riding ahead of the main energy center and ahead of the surface front.  This will have less instability to work with as it moves from 18Z in Western New England to a position off the coast by 00Z.  At least some convective activity seems likely with this line.  The next comes along the surface front, which will feature great low level convergence and available surface based instability, but drier air aloft and lower topped convection.  Any storms that do develop in the first round will feed off of a moist sounding to produce heavy downpours and the potential for wet microbursts in an environment featuring 50-60+ kt winds through a very deep layer of the atmosphere, mostly unidirectional out of the southwest, implying straight-line wind damage is a threat with the afternoon convection from 18Z onward, and winds will remain strong for the evening line, too.

It's over Tuesday night and dry/cool advection settles in for a nice Wed/Thu.  Next storm has huge differences between the guidance for Friday, with the ECMWF, Canadian GEM and GFS running the gamut, but most agree on a healthy tropical tap into New England for developing precip.  The concern I have is lingering cold in Northern New England so I've kept a chance of some snow there.

Matt

ACCUMULATING SNOW FOR MANY...HIGHEST AMOUNTS THROUGH CENTRAL NEW ENGLAND...COOL BUT QUIET WEEKEND AHEAD

First off, please see post below this one for information on new weather website at nationalweatheronline.com.  This site is right up our alley for folks like you and I - a place where anyone can go, post images, video, observation and analysis about weather *as it's happening.*  Check out the post on it, check out the site and sign up to be a correspondent if you're so inclined.  The site just launched 12 hours ago, so stick with it as it spins up in the coming weeks.

Weatherwise, digging in for the next tricky winter/spring weather event.  A couple of things to keep in mind for this event that don't pertain to the models or the guidance, just to nature:

1) This system has a history of flexing its muscle of energy aloft.  While snowfall amounts in Iowa may have only been a few sloppy inches, thunder snow and sleet was reported this morning.

2) There is plenty of moisture with this system as it's obtained a good tap out of the Gulf of Mexico, that actually is part of a loop of air coming all the way out of the Tropical Atlantic.  This was discussed here two days ago and is an important player - the contributor that has resulted in a boost of QPF amounts from the guidance in this morning's runs...not unexpected to those who read about the moist air supply or saw it for yourselves over the past couple of days.

3) The storm is fast moving.  So, while it may bring lots of moisture, it only has a limited time to dump on New England.

4) All spring storms have elevation dependency.  I suppose there's an exception to every rule, but this storm will not be the exception.  Elevation matters.  It matters when you have warm bubbles of air trapped in valleys, and it matters when you're cold advecting aloft first, then mixing down.  We have both of those factors.

5) This is different from the last storm.  It's easy to be a bit gun shy on snowfall after the last storm, in which ample cold and dry air was, in the end, overwhelmed by enough warmth for a cold rain in many spots.  One would be intelligent to wonder if that will happen this time, as well, but remember that we're not dealing with a weak southeast or east wind, but rather a strengthening northeast wind in ageostrophic flow (air flowing toward the developing area of low pressure south of New England).  This means once cold air is into a location, it will not relent until diabatic heating (diurnal warming) turns the temperature around during Friday afternoon for a rain/snow mix with little additional accumulation.

So these assumptions leave us with a good foundation to build off of in the forecast.  We also know the GFS has tended to outperform the NMM time and again this winter, and this forecaster strayed only once and was burned.  This time, the NMM actually was the first to hint toward a more northward precip axis, but seemed much too far north early in the game.  The difference has narrowed as each has given some ground toward the other, and I think the GFS forecast - in line with the ECMWF and Canadian Operational and Ensembles - is the way to go.  This puts over .75" of precip in the heaviest axis across Northern MA and Southern VT/NH, but this will not be an all snow, nor will the snow to water ratio be very high.  In fact, even in Central and Southern New Hampshire the warm antecedent boundary layer will mean dynamic cooling will get the lower few thousand feet of the atmosphere only marginally below freezing, meaning ratios may be between 6 and 9 to 1, depending on location, so we're not looking at widespread 8" amounts under the precip max.  Instead, a widespread 4"-6" seems most likely.  It's a bit of a conundrum trying to figure out what to do farther south, where mostly rain will fall - about .25" to .50" of it - but there will be a southward snap of the rain/snow line during the day as a strengthening wave of low pressure moves southeast of Cape Cod and tugs cold air southward.  Probably a dusting to solid coating for these areas of Southeastern MA, but during the afternoon I have to think that most areas - even those with the most snow - will see drastically reduced accumulation rates as the boundary layer rebounds a bit in temperature.

As a northwest wind takes over, drying will take place but I'm not sure evaporation will beat out cooling, meaning black ice is a potential problem.  The cold surface dome of air available from the anticyclone strengthening over Eastern Canada will expand into New England on Saturday with cool temperatures and a biting wind chill for many, before the surface ridge axis drifts overhead Sunday for a quiet day.

Looks like we do it again Monday/Tuesday, but this time there seems to be very good agreement on the storm track being over Western New England as the slow moving, amplified ridge axis sits off shore, and this should thrust the warm front through on Monday with some late rain and snow, then warmth Tuesday with a chance of convective showers and thunder when the attendant cold front to the surface low swings through New England.

That's all for today.
Matt

NATIONALWEATHERONLINE.COM - A NEW WEBSITE DEVOTED TO REAL-TIME, MULTIMEDIA WEATHER OBSERVING FROM REAL PEOPLE...CHANGES AFOOT HERE AT MATTNOYES.NET, TOO

There's a new website for me to share with you that has been in development at NATIONALWEATHERONLINE.COM.  I'm excited to be a contributor to the site, and it's based on the concept that weather enthusiasts nationwide want to see what's really going on in neighborhoods across the country, and are eager to share what's happening in each of our own towns and cities.

The site is free to join, and aims - through correspondents nationwide - to bring regional coverage of weather events in real-time utilizing photographs and video, as well as written observation and analysis from members.  In time, the site is designed to serve as a forum not only for weather enthusiasts, but also for the media to find out what's really happening, as it's happening, and utilize the images, video and analysis submitted by correspondents to report more accurately and intelligently to the general public.

Check out the site and you may decide you'll want to contribute as a correspondent from your community.  In addition to the regional pages for real-time weather analysis, there's also a permanent photo gallery much like I have here on my New England Photos page, but for the entire nation, so shutterbugs may want to submit photos to that site, as well!

Finally, there's a National Weather and Headlines Page on nationalweatheronline.com, and from this point forward I will link to that site for latest weather news, rather than post it here to my own website.  I've enjoyed bringing you the latest weather stories, but this new national site will do just as well if not a more thorough job getting the latest weather news to you in a timely fashion.  In the meantime, I'll continue to provide my forecasts on my Forecast Page and discussion on my New England Weather Analysis Page, but you will definitely see a revamp of this page (simpler, but better layout) in the weeks to follow.  With the upgrade to the NECN Weather Page, and an upcoming blog for the station, that means a revamp of my own site so as not to duplicate what my teammates and I will be doing for NECN.  In the meantime, I hope you end up as excited about being a correspondent for nationalweatheronline.com as I am!

-Matt

NATIONALWEATHERONLINE.COM - A NEW WEBSITE DEVOTED TO REAL-TIME, MULTIMEDIA WEATHER OBSERVING FROM REAL PEOPLE...CHANGES AFOOT HERE AT MATTNOYES.NET, TOO

There's a new website for me to share with you that has been in development at NATIONALWEATHERONLINE.COM.  I'm excited to be a contributor to the site, and it's based on the concept that weather enthusiasts nationwide want to see what's really going on in neighborhoods across the country, and are eager to share what's happening in each of our own towns and cities.

The site is free to join, and aims - through correspondents nationwide - to bring regional coverage of weather events in real-time utilizing photographs and video, as well as written observation and analysis from members.  In time, the site is designed to serve as a forum not only for weather enthusiasts, but also for the media to find out what's really happening, as it's happening, and utilize the images, video and analysis submitted by correspondents to report more accurately and intelligently to the general public.

Check out the site and you may decide you'll want to contribute as a correspondent from your community.  In addition to the regional pages for real-time weather analysis, there's also a permanent photo gallery much like I have here on my New England Photos page, but for the entire nation, so shutterbugs may want to submit photos to that site, as well!

Finally, there's a National Weather and Headlines Page on nationalweatheronline.com, and from this point forward I will link to that site for latest weather news, rather than post it here to my own website.  I've enjoyed bringing you the latest weather stories, but this new national site will do just as well if not a more thorough job getting the latest weather news to you in a timely fashion.  In the meantime, I'll continue to provide my forecasts on my Forecast Page and discussion on my New England Weather Analysis Page, but you will definitely see a revamp of this page (simpler, but better layout) in the weeks to follow.  With the upgrade to the NECN Weather Page, and an upcoming blog for the station, that means a revamp of my own site so as not to duplicate what my teammates and I will be doing for NECN.  In the meantime, I hope you end up as excited about being a correspondent for nationalweatheronline.com as I am!

-Matt

NATIONALWEATHERONLINE.COM - A NEW WEBSITE DEVOTED TO REAL-TIME, MULTIMEDIA WEATHER OBSERVING FROM REAL PEOPLE...CHANGES AFOOT HERE AT MATTNOYES.NET, TOO

There's a new website for me to share with you that has been in development at NATIONALWEATHERONLINE.COM.  I'm excited to be a contributor to the site, and it's based on the concept that weather enthusiasts nationwide want to see what's really going on in neighborhoods across the country, and are eager to share what's happening in each of our own towns and cities.

The site is free to join, and aims - through correspondents nationwide - to bring regional coverage of weather events in real-time utilizing photographs and video, as well as written observation and analysis from members.  In time, the site is designed to serve as a forum not only for weather enthusiasts, but also for the media to find out what's really happening, as it's happening, and utilize the images, video and analysis submitted by correspondents to report more accurately and intelligently to the general public.

Check out the site and you may decide you'll want to contribute as a correspondent from your community.  In addition to the regional pages for real-time weather analysis, there's also a permanent photo gallery much like I have here on my New England Photos page, but for the entire nation, so shutterbugs may want to submit photos to that site, as well!

Finally, there's a National Weather and Headlines Page on nationalweatheronline.com, and from this point forward I will link to that site for latest weather news, rather than post it here to my own website.  I've enjoyed bringing you the latest weather stories, but this new national site will do just as well if not a more thorough job getting the latest weather news to you in a timely fashion.  In the meantime, I'll continue to provide my forecasts on my Forecast Page and discussion on my New England Weather Analysis Page, but you will definitely see a revamp of this page (simpler, but better layout) in the weeks to follow.  With the upgrade to the NECN Weather Page, and an upcoming blog for the station, that means a revamp of my own site so as not to duplicate what my teammates and I will be doing for NECN.  In the meantime, I hope you end up as excited about being a correspondent for nationalweatheronline.com as I am!

-Matt

MILD MIDWEEK...GRADUAL COOLING TO LEAD TO WINTRY SCENARIO BY FRIDAY FOR MANY

A weak cold front will continue to cross New England Wednesday afternoon and evening, bringing a slight wind shift from southwest to west, and a slightly cooler and drier airmass.  The new air still won't be cold, however, and the region will recover back into the 40s and 50s on Thursday.  Nonetheless, a storm with some snow likely looms for Friday.

Two low pressure centers are present in Southern Canada - one just north of Maine as of this writing and the other over Lake Superior.  Both are associated with shortwaves (disturbances) that are traveling along the fast jet stream winds flowing near New England.  With the jet stream nearby, there's not much impetus for a major change of airmasses, meaning no deep drive of air either north or south, but rather a wavering frontal boundary that will continue to see-saw a bit in the coming 48 to 72 hours, but generally will trend southward as a defining characteristic emerges onto the map - a strengthening high pressure dome that will build across Central and then Eastern Canada.  The clockwise flow of air around this high pressure dome will force cold air southward behind a cold frontal passage on Thursday, associated with the second shortwave moving out of the Upper Great Lakes.  Of course, the interaction of warm air to the south of New England and cool air to the north will continue to make for challenging forecasting.  First, high temperatures Wednesday afternoon have warmed nicely owing to sunshine the first half of the day and an active west-southwest wind.  That said, the cold front pushing gradually across New England from the northwest may be weak, but still is having a noticeable effect as it brings colder air both at the surface and a bit more impressively a couple of thousand feet above ground level, which has been the impetus for new cumulus cloud development above warm ground.  This first front will settle south of New England where it will effectively die a slow and quiet death, but the cool air behind it will allow temperatures to drop below freezing in most New England communities overnight Wednesday night beneath mostly clear skies, though perhaps some clouds near the Canadian border ahead of the next shortwave.

The shortwave crossing New England on Thursday will straddle the Canadian border, but with a fast zonal flow there are so many shortwaves that another will ride toward the Southern half of New England later Thursday and with the approach of the surface cold front from the northern vorticity maximum (energy maximum), the surface convergence will help to focus afternoon showers in Southern New England - especially CT, RI and Southeast MA - while cold advection may touch off instability snow and rain showers in the North Country.  In between, the most sun will be found tho clouds will increase with the confluence of disturbances as the day progresses.  Of course, this front will be the main show, and as mentioned yesterday, I like the GFS depiction of driving the front thru New England to a position south of the South Coast by Thursday night into Friday.  I support this scenario given the building anticyclone in Eastern Canada which will still be strengthening, and the propensity for a northeast wind to carry air southward effectively in New England.  As discussed yesterday, this creates a path for the next surface low to travel on Friday, passing south of New England which will be important because of the ageostrophic flow that will maintain a northeast wind.  For all of the moisture that plays into this system, it's become admittedly less impressive as we near it, largely because the timing as become quicker, owing largely to the southward surge of the cool air so effectively that the QPF and surface forecasts out of my preferred GFS model essentially supports one storm for the Southern half of New England on Friday and another for the Northern Mid-Atlantic with a Southern New England graze Friday night.  But there's a huge problem with this line of thinking, which is that the 500 mb heights and vorticity (average temperature to abut 20,000 feet and energy at that level) prog doesn't support this.  In fact, the GFS vorticity forecast takes the vorticity maximum directly over the MA/VT/NH border Friday night.  Now, I can see how the front pushing south would separate the deep moisture southward from the core of the vorticity maximum, but I think trying to keep the precip almost entirely south of New England with the second round overnight Friday night is wrong.  Whether this is owing to improper handling by the convective parameterization or an unfair weighting to other low level atmospheric conditions I don't know, but I do know that surface follows upper air pattern in a fast and strong jet stream flow, not the other way around.  This cautions me against trusting in a miss Friday overnight, and therefore I'll keep a chance of precip in the forecast thru the overnight.

Precip type will be a challenge, of course, but rain/snow line should come pretty far south with good northeast cold advection drain.  Have been approximating Central CT/RI/SE MA with a small zone of freezing rain north of that line and mostly snow farther north, but that is an estimate right now and is only based on my assumption that the historically difficult task of carrying a subfreezing boundary layer farther south than that will not be achieved.  Where it will be mostly snow, I've been giving an early estimate of 2"-5", the lower end of which is close to a 10:1 ratio on forecasted QPF, and the upper range of which seems unlikely to verify at first glance.  But keep in mind two things:   1) This is an early estimate and I am being tremendously honest about not just the possibility but rather the LIKELIHOOD that the forecast will be ammened, as is often the case in spring storms of vastly different airmasses so close together, and 2) If my hunch on the farther north track is right, these amounts *could* be vastly underdone when Friday night is figured in, so I figured this introduces the potential for plowable snow and leaves the door open for fine tuning.

Either way - a north or south track Friday night - this thing keeps moving and that means Saturday brings instability cumulus with scattered snow showers, especially in orographically favored areas.  Cold surface air will be available from the anticyclone in Eastern Quebec and will do its thing.  Sunday brings the ridge axis which means subsidence - equating to lighter wind, but cool conditions.

That's all for today.
Matt

A ROUND OF SNOW SHOWERS FOR MANY TUESDAY NIGHT...WINTRY MORE LIKELY THAN WET FOR MOST AT WEEK'S END

A few items of interest in the coming several days, with the Friday event the most intriguing, for sure.  As for our Tuesday, moisture streaming north of developing ocean storm surprised me a bit with the light flurries reaching Martha's Vineyard and Nantucket but that's been swept east as ridge of high pressure crests overhead and plenty of dry air locks in sunshine...at least until high and middle altitude clouds advance from west to east ahead of the approaching shortwave (disturbance).  This shortwave is evident on satellite and radar imagery with a swath of snow pushing across Michigan, and the most intense dynamic lift will move across Northern New England overnight Tuesday night, assisted by topography for enhanced lift that will breed heavier squalls of snow.  Resultantly, while most of Northern New England will pick up between a coating and 2" of snow, the mountainous terrain should squeeze out at least 3", and exceptionally favored spots like the higher terrain from Jay Peak, VT, through the Northeast Kingdom and into the high terrain of the Whites will pick up closer to 5".

There's milder air that streams in behind tonight's shortwave as the warm sector will be somewhat dirty (lots of clouds), but with a strengthening southwest and west low level wind flow, this will encourage downsloping and therefore breaks in the overcast that should grow during the afternoon, and the input of insolation will help to boost temperatures into the 50s for Southern New England.  Slowly, winds will shift to blow from the west and later from the west-northwest Wednesday afternoon as the attendant cold front slowly slithers through New England, and this begins a slow drain of cold air across the region.  Of course, when I say "slow," I really mean it for most spots, with only one to three degree Celsius drops at 850 mb, largely because the parade of shortwaves fail to amplify enough to lower the 500 mb heights overhead, and this eliminates any impetus for a cold surge out of Canada to come all at once except for Northern Maine.  At the surface, however, a large dome of high pressure will strengthen as it moves from Hudson Bay to Quebec, and the expanding and strengthening clockwise flow of air around it will force cold air advection southward through New England, snaking the sluggish cold front even farther south until it sits south of Long Island by Thursday night.  With 850 mb temperatures below freezing and all of the column except the boundary layer below freezing by early Friday...not to mention surface dewpoints running 30-35 degrees...this sets us up for a likelihood of snow when the most meaningful of the shortwaves moves through on Friday.  And that's been one change in the guidance - to speed up the arrival of the shortwave - which has been evident in the 06Z and 12Z cycles but seems fairly well agreed upon.  Of course, this shortwave will be loaded with moisture owing to the well defined low level jet that cranks out of the Gulf and flows normal to the frontal boundary draped across the Mississippi River Valley and the Central Plains.  Rather amazing to follow the boundary layer wind flow and see that it's a continuous loop of air from the Tropical Atlantic over the Caribbean, through the Yucatan, up the Western Gulf and into Texas, then along the frontal boundary into New England before wrapping back around the Western Atlantic anticyclone!  This should reinforce the potential for substantial moisture entrainment and I certainly don't think we should be undercutting the precip amounts on the operational guidance given this moisture availability.  Saving us will be the relatively quick movement, and if the Friday shortwave is indeed the main show, this cuts back on the number of waves to come as the front is pushed southward sooner.

As for precip amount and type, the northern swath of the precip shield will be vulnerable to a heavy spring snow that should total more than half a foot.  Nailing down the location of this is, of course, the challenge, and there are some big differences rearing their ugly head with the NMM pushing sleet and rain as far north as Central/Northern New Hampshire, and the GFS a good deal farther south with a mostly snow scenario into Northern MA.  A bit torn as a forecaster here given the NMM's superior resolution of the boundary layer suggesting it should have a better handle on how the shallow cold will behave, but the fact that synoptics of a strengthening anticyclone and a deepening cyclone south of New England with a northeast wind strengthening in ageostrophic flow tends to support a winter scenario.  That's the direction I've gone - toward synoptics and toward what I believe to be the historically favored scenario given the setup, which would bring the potential for significant spring snow into Northern MA, with a swath of freezing rain likely through the interior south of that all the way into parts of the Pioneer and Lower CT River Valley, then rain farther south and closer to the coast from Boston southward.  That said, this is obviously an early estimate and we'll have to see how things evolve.

I can tell you I also followed the trend of bringing drying in for Saturday - especially later in the day - and went colder than guidance for Sunday owing to the available surface cold dome to our north that will be tapped.

Matt

The warmth won't last long with

 

QUIET START TO THE WEEK...WET OR WHITE TO END IT

Very crunched for time today so will be concise.

High pressure remains in charge and after Clayton Lake, Maine, took the prize of coldest temperature with -34 F this morning, should be some 10 to 20 below zero readings tonight but cloud debris will keep average North Country temps from being quite as cold as night past.  This cloud debris blowing off Lake Ontario has brought flurries as far east as Northern VT but now some high clouds will start streaming into tonight, as well.  Nonetheless, mostly dry air means mostly clear sky for New England with a light and variable wind having a northwest tendency early and southerly tendency late

Tuesday starts with lots of sun that fades late as warm and moist advection commences ahead of shortwave trough that will mostly run thru Ontario and Quebec, dragging occlusion and associated warm/cold front thru New England Tuesday night with scattered showers. Temps should be warm enough in the boundary layer for mostly raindrops in CT/RI/SE MA, a mix most of MA and Srn NH/VT and mostly snowflakes farther north but the combination of weak dynamic lift this far south of the shortwave and limited surface convergence, as well.  Farther north, at least a coating of snow for most areas but orographically favored areas will pick up 1"-3" Tuesday night into Wed AM.

I like the idea of being stubborn with breaking the clouds on Wednesday with what will be quick warm and then cool advection, but a downsloping southwest wind in Southern New England will favor some breaks and with mild boundary layer air in place, 50+ seems reasonable in Southern areas.  The cool front settles south late Wednesday into Thursday and sets up a Thursday night through Saturday pattern with tons of potential.  With a front laid across New England and trailing back west to the Central Plains where it meets a low pressure center that will get the low level jet cranking out of the Gulf and provide a moisture feed to the front.  This begins the process by which ripples of low pressure will continue to move along the front at the same time an anticyclone strengthens over South Central Canada and muscles southeast.  This is a situation that needs to be monitored for substantial rain and snow from the Midwest to the Ohio Valley to the Northeast with accumulating possible from Chicago to Boston.  Of course, the end result depends upon the interaction of the cold and moisture and just how far south the cold can muscle, but with the Canadian high at 1028 mb on Friday and 1032 on Saturday, it's strengthening which means the push of cold is strengthening, raising the stakes for accumulating snow in much of New England especially Friday and Saturday.  Definitely a watcher.

Matt

BLIZZARD CONDITIONS IN NORTHERN MAINE...DAMAGING WIND GUSTS ELSEWHERE

Pretty behind today but wanted to get something out to address wind in the short term and early next week in the longer term.

Surface and upper lows become stacked just northeast of Aroostook County, ME, overnight tonight and this brings the storm to full maturity as it moves northeast into New Brunswick.  The result will be wraparound snow redeveloping for Northern ME and the mountains of ME and though the intensity will actually be equivalent or less than this afternoon's snow in some of these communities, the wind will only get stronger thru the night and the combination of falling and blowing snow may reduce visibility to blizzard conditions for a time overnight Thursday night from the ME mountains to the Crown of ME...where I just got word the blizzard warning is up from NWS as of moments ago.  Of course, for the remainder of New England the wind will be the big story beneath drier air advecting southeast across New England and breaking the overcast.  Subsidence behind the vorticity lobe moving overhead will also contribute to the clearing.  Nonetheless, with the storm bottoming out northeast of ME tonight into Friday, the wind field will be expanding dramatically, and this keeps New England in the mix for potentially damaging wind.  Of course, "in the mix" has two meanings here, since a well mixed atmosphere will prevail and allow for mixing from 875 mb Thursday evening and then again on Friday.  Overnight Thursday night, some nocturnal cooling of the boundary layer may decrease the mixed height a bit, but winds will remain active and gusts to 50 mph or greater will remain possible, and that will continue on Friday.  Isolated power outages will be possible with the potential for limbs to break onto power lines.

The drier air keeps coming into the weekend as the northwest flow aloft piles it in, and also ensures the next shortwave (disturbance) will miss to the south of New England on Saturday, then a break in the action on Sunday.  Temperatures will fall into the 20s at night, which means a cool sunrise service on Easter Morning, but afternoon temperatures will rise both Sat and Sun with good mixing.

The trend for Monday night into Tuesday has been for a farther south and east solution, which isn't a huge surprise given what was discussed here in last evening's discussion (see below) but I do like the new ECMWF (European guidance) solution of bombing the low off the coastline, and this still keeps the potential for an expansive moisture field that may still graze New England on Tuesday, and it would be cool enough for snow, so this is still something to watch, even though the bulk of the storm would stay southeast.  Also, large swell would seem probable at the south coasts midweek next week so surfers have something to keep an eye on, as well.

Matt

WEDNESDAY DISCUSSION PART 2 - TAKE ON EARLY WEEK STORM FOR NEXT WEEK

As promised, this is part two of today's discussion - the first part is below.  This is to follow up with thoughts on the potential for a storm early next week.

It's important to understand the difference between a forecast for mass consumption, and what really goes on with the forecast.  That is, on TV today I mentioned that there "may be a storm at the beginning of next week, and it may favor snow for New England, but it's still so early that so much can change, so we'll see what happens."

Of course, from a meteorological perspective, the best forecasts often come when the most information is available for pattern recognition from well in advance to right before the event.  The longwave pattern will be the first and most important part of the equation to nail down, and the general trend is to watch today's storm deepen dramatically, becoming stacked beneath an intensifying upper low that pulls northward to the mouth of the St. Lawrence River.  Another low will deepen south of the Aleutian Islands in the coming days, and this encourages ridge development over the Western U.S.  Of interest by Monday is the orientation of the upper low north of New England, the confluent flow over the Northeastern U.S., and the upper level flow dropping southeast out of Canada and into the Eastern U.S. trough.  Perhaps the most important player in this is the unloading of arctic energy from the polar vortex by the north pole, dislodged when the upper low over the St. Lawrence expands and retrogrades westward, increasing the northerly flow and sending a strong chunk of vorticity and cold air southward.  This drops into the longwave trough axis over the Great Lakes at the same time a strong southern stream shortwave (disturbance) rounds the base of the trough over the Southeastern United States, tapping the Gulf of Mexico for ample moisture.  Think about the amazing recipe that's coming together in even this most basic description - air from the North Pole and the polar vortex (the heart of cold air this side of the Northern Hemisphere) dives south at the same time deep Gulf of Mexico moisture and warmth streams north.  The merger could be amazing, and though the differences in projections are large, almost all guidance has good agreement on this storm absolutely bombing and becoming a mega-storm.  The problem becomes how to handle the merger which is essential to development of the storm - timing, track and intensity - and the best we have is a combination of guidance and our own pattern recognition.  Let's start with the pattern recognition.

I'd like to see the upper low retrograding quicker across Eastern Canada and to Hudson Bay, because this would assist in nudging the longwave trough a bit farther west.  At this point, the forecasted position of the upper low keeps the trough axis just far enough east that the storm would really take off under a jet streak that would be moving over the Mid-Atlantic coast, bombing the storm just a bit too far southeast to affect New England, though under this scenario the storm would begin to undergo intensification as it moves across the Mid-Atlantic coast and that would deliver a decent snowstorm by early spring standards to the Northern Mid-Atlantic.  The ECMWF is the farther west in its solution - but also has a longwave pattern that is the closest in agreement to the Ensemble solutions of the GFS and Canadian - and allows the storm to explode quickly off the coastline owing to strong baroclinicity.  This is an important facet that probably is being handled better by the ECMWF than the remainder of the guidance given the confluence of airmasses taking place, and I think it's important to acknowledge the potential for dramatic strengthening not far off the coastline.

So, right now a bomb is likely, probability of a bomb to affect the Mid-Atlantic with snow is high, with a pounding nor'easter is moderate, but with a storm as far north as New England is low probability, in my opinion, with what we have right now.  That said, that forecast is based upon the consensus in model guidance and we should watch for westward shifts in the upper low over Hudson Bay as an indicator that the longwave trof axis will come west and the storm may develop closer in and farther north.

Matt