MATTNOYES.NET - Weather Website & Blog

TWO TROPICALLY-INFUSED STORMS TO AFFECT NEW ENGLAND THIS WEEK

Welcome to the weather blog - a regular Monday through Friday discussion of the weather!  While the discussions usually will only come on days I'm working, I'll issue special updates when the weather warrants.  I will always post to let you know when no discussion is expected if I'm away on vacation, etc. - if no update is here and no info is available, that likely means the server has temporarily gone on the fritz and I will update as soon as technically possible.  You'll find a quick weather synopsis linked to the daily forecast at the top of the page, a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow by mid-afternoon. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

General Weather Summary:

There are three primary storm centers that are affecting the United States to begin this new workweek - one is spinning slowly northeast parallel to the Eastern Seaboard, another is located over the Northern Great Lakes with a front draped south through the Midwest, and the final storm is pushing into the Pacific Northwest.  Certainly this is an indicator that the weather will stay active across the country, including right here in New England.

The most immediate of the storms to affect us is, of course, the low pressure center spinning off the Delmarva Peninsula Monday morning - the same storm that launched rain bands over New England on Sunday.  For most of Monday, the deep moist flow through several thousand feet of the atmosphere will continue to spin plenty of clouds into New England off of the Atlantic Ocean, along with a few showers as east winds will gust over 30 mph for coastal locales Monday afternoon.  But there is more at play in Monday's weather setup than simply a moist ocean flow, as a cold front that died over New England early this past weekend is still stalled across the six-state region.  This stationary front is evidenced by a pronounced change in temperature and dewpoint - the measure of the amount of moisture in the air - as one moves from south to north across especially Southern New England.  Laid from Boston to Hartford on Monday, this front will represent the dividing line between an airmass producing temperatures into the 60s south of the front, and temperatures in the 40s and 50s north of the boundary.  Near to the clash of airmasses, fog will linger for awhile Monday and showers will find added focus through the day.

Meanwhile, farther south and more squarely into the envelope of tropical-origin air surrounding the storm center, better organized rainbands continue to spiral around the well-defined storm center.  As the storm nudges northeast through the day on Monday, the rainbands also will nudge northward, encompassing Connecticut and Western Massachusetts during the afternoon and early evening, then continuing to spread northward overnight Monday night.  Though general rainfall amounts will total between half an inch and one inch in most of Central New England, eastern areas may exceed one inch, and a band of heavier rain across the state of Maine, embedded in a deep tropical flow, will total in excess of two inches, with much lesser amounts in Northwestern New England.  These amounts may be enough to prompt localized flooding of streams and streets in parts of Central Maine by midday Tuesday.

Otherwise, with the storm center ready to move directly across New England on Tuesday, clouds and showers will linger through most of Northern and Western New England.  In eastern parts of Southern New England, however, indications are that a sliver of dry air may move in just long enough to break sunshine out in Eastern MA and Southeastern NH.  If this happens, the air is plenty warm enough in nature to support temperatures soaring into the 60s with a few spots possibly touching 70 degrees, while the remainder of New England stays much cooler.

This storm will be kicked out by another disturbance marching east across the Great Lakes, and a relatively mild break in the action will come on Wednesday, when only a few showers are expected.  By Thursday, a storm pushing through the Pacific northwest early in the week will be traversing the nation's midsection, pulling mild air ahead of it, but tapping deep tropical moisture once again.  This will mean another slug of rain, heavy at times, later Thursday into Friday when at least an inch or two of rain are likely to fall.  Behind this storm, colder air will pour into New England, marking the end to our above normal temperature streak, and bringing in several days of at and below normal temperatures.

Technical Discussion:  None today.

Matt

DECENT VETERANS' DAY...WETTER END TO WEEKEND AHEAD

Welcome to the weather blog - a regular Monday through Friday discussion of the weather!  While the discussions usually will only come on days I'm working, I'll issue special updates when the weather warrants.  I will always post to let you know when no discussion is expected if I'm away on vacation, etc. - if no update is here and no info is available, that likely means the server has temporarily gone on the fritz and I will update as soon as technically possible.  You'll find a quick weather synopsis linked to the daily forecast at the top of the page, a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow by mid-afternoon. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

General Weather Summary:

As New England enjoys continued mild conditions after record warmth in Portland, ME, with a high of 69 degrees yesterday, cold air remains locked in Canada, where daily high temperatures were held in the single digits across the Northwest and Western Provinces at the end of this week.  Cooler air - though not deep cold - has been seeping southeast across Central Canada, and though that air has lowered temperatures Friday from where they were Thursday.

The new airmass in place on Friday is dry, and though it's somewhat cooler, we'll still find maximum temperatures above normal for the date with an active westerly breeze sloping down off the hilly terrain of Western New England, helping to nudge most temperatures in Central and Eastern New England to near 60 degrees.  Though this bubble of cool and dry air will allow for temperatures to fall Friday night, yielding a cool start Saturday morning, sunshine should be able to assist in a rebound to start the weekend.  This comes as a new, very strong disturbance dives into the Ohio Valley on Saturday, spawning a storm center to our west.  The counter-clockwise flow of air around this storm will mean a strengthening south and southeast flow of air through the day Saturday, and after sunshine early, clouds will increase well in advance of this storm with a white or even gray sky to end the day, with intervals of clouds and sun through most of the day.  By Saturday night, the approach of the strong disturbance aloft will result in the strengthening of a low pressure center southwest of New England that will move south of Long Island.

This is where there are changes to the forecast from yesterday, as the trend has been for a bit more southward suppression and slower progression of the storm center.  So, whereas yesterday I was thinking we'd have windswept showers scattered about with a west wind, the new slower trend changes this dramatically.  Instead, we're looking at a system now that will creep parallel to the coastline and maintain an EASTERLY wind deep through the atmosphere from surface to 20-25,000 feet in altitude!  This seems like a dramatic change to the non-weather savvy, but in reality it is a shift of couple of hundred miles south in this low - a relatively short distance in the scope of the global weather pattern, but important here in New England.  This deep easterly flow will mean a consistent supply of Atlantic moisture - also tapping the Tropical Atlantic - that will light up a swath of heavy rain to sweep from New Jersey into Southern New England on Sunday.  With a strong high pressure cell to the north of New England - but limited cold air available - winds will increase Sunday along coastal locales, especially, though most of New England will find the winds kicking out of the east.  Rains will be quite heavy with this slow moving band, and the slow speed of it will mean flooding will be a concern later Sunday and Sunday night in Central and Southern New England.

We've already seen a major shift in the timing of this storm once, so naturally the timing later in the period is still uncertain heading into Monday, though right now I would assume this slow moving band of rainfall will still be pestering Central and Northern New England, when flooding concerns will spread north with the rainfall.  This delays improving weather conditions for most locales until Tuesday, when showers are still likely to linger in the North Country, though enough cold air may bleed southward by that point for a few snow showers in the North.

At least some return of milder air still is likely in the cards for midweek before another developing storm seems destined to deliver another shot of intense tropical moisture toward the end of the week, and that may once again raise concerns for flooding.  It does appear as though that storm may be the one to break the back of the mild streak - at least for nearly a week - as temperatures will return to below or near normal values.

Matt

Matt's Technical Meteorological Discussion:  Updated Friday, November 10 at 11:55 AM

Obvious trend is for slower and farther south and that trend has continued in the 12Z runs this morning.  Have reviewed both the slower NMM and GFS today, tho at this point would like to see additional runs before backing off Sunday precip, as I have to assume both are underdone here in NewEng.  Reasoning is a deep S/SE flow thru most of the atmosphere and a low level baroclinic zone settling S on Srn edge of strong anticyclone over Ern Canada that should result in blossoming precip Sun across at least Srn NewEng.  Even if upper low does take farther S track 12Z guidance suggests, deep S flow would still usher deep moisture into NewEng.

In the meantime, near calm winds and only a few high altitude clouds Fri Ngt will mean cool but not cold conditions, and sunshine to start Sat will provide good mixing, and haven't changed thoughts on a mild Sat for most of NewEng, tho not near Canadian border where clouds thicken quickly assoc with frontal boundary producing snow thru upper great lakes this morning and that will extend across North Country Sat eventually producing showers by late in the day.  Farther S, most moisture will be above 500 mb, but will thicken enuf for OVC conditions by later Sat afternoon.  Still, mild increasing sfc wind and early insolation will bring temps up.

Am holding the line of steady but slow progression of upper low Sun/Mon and bringing some improvement for Tue, but as mentioned above, if 12Z trend is correct, the entire system will have to be slowed down.  If my thoughts hold, however, we're looking at flooding concerns for Srn NewEng Sun Ngt and then those same concerns translate N on Mon thru at least ME where ground is already saturated.

This weekend's storm - regardless of what it delivers for precip - still does not deliver a shot of cold air, and instead allows more tropical origin air to move in for a milder midweek.  The next strong Pacific shortwave, however, will bring another round of tropical moisture toward next week's end, and by that point enough low level and surface cold will be build far enough south in Canada to be tapped for a stretch of about 5 days.  Thereafter, the trend may be to a few moderate overrunning events with sfc cold but rebounding warmth aloft.

Enjoy the weekend - I guess we'll all see how this plays out together!

Matt

Wednesday's Discussion:

3:05 PM:  Well defined packet of tropical moisture streaming N up seaboard today is focused N of sfc low center and upper low.  Still a surface/llvl thermal and isodrosothermal (dewpoint) boundary stretched across Central NewEng to the coastal plain of ME and this will continue to focus heavy rains from Hudson Valley thru Wrn MA to ME coast with heavy rains SE of that boundary, as well, and sharply lesser amounts farther northwest.  FFG values 2-3" and this may cause a problem in Srn CT where flood watch is up, as well as Southern to Midcoast ME.  SE wind will freshen ahead of sfc low pressure passage as it moves SE of NewEng and brief gusts 30-40 mph are possible Cape Cod this eve.

Behind this storm, wind shifts to NW, but no immediate cold air source is present, so this leaves a weakly downsloping flow with mild air to the tune of +10 C at 850 mb and +12 to +14 C at 925 mb.  Subsidence sets in during the heart of the day, and this should be sufficient to poke holes in the OVC that will allow for rather rapid temp rises in warm airmass, climbing into the 60s many areas.  Pioneer Valley and perhaps Boston area both stand a shot at 70 with downsloping/sun combo, depending on how much insolation we see.  Have held chc thunder only for Wrn NewEng, as best chance is across NY State where strong diffluence and PVA comes thru during diurnal htg, not arriving into Wrn NewEng until eve, but strong enuf diffluence above warm enuf air to warrant downpour/thunder in the fcst.

This sfc cold front will be progressive, but while air behind it is noteably colder, that's not saying much when you're starting out so anomalously warm, and thermal profile with good mixing and downsloping flow Fri still supports an average high just over 60 with favored downslope areas warmer still.  Have continued to hedge way above MOS for Sat as operational guidance suggests a relatively clean warm sector with possible contamination above 400 mb, but strong thermal advection on Sat.  There are two concerns with this gamble: 1) Southeast sfc flow as low strengthens and doesn't track quite far enuf north to guarantee S or SW flow, meaning tendency is there for an onshore component, and that's frankly why I've gone mid 60s and not closer to 70.  2) Increased llvl moisture thanks to this onshore component.  If that happens, going to have to slice and dice my temps.

Looks like cyclogenesis will occur overhead on Sun as anafront becomes active with wave, and wave will intensify over Ern NewEng.  Still timing diffs on this, but GFS Ensemble is progressive, Canadian and its Ensembles quite slow, and ECMWF seems a good compromise, but leaves Neweng quite windy, chilly and showery on Sun...tho not cold enuf for wintry precip.  Quick shot of cold behind this system for early in the week gives way to more mild anomaly before a rainstorm Thu with good tropical moisture tap again gives way to slug of anomalous cold for a few days.  The warmer than normal pattern returns thereafter, however, with little available deep cold making it into the lower latitudes...for now.

Matt

Monday's Discussion:

1:35 PM:  Early AM shortwave brought new snow to Nrn and Central ME while freezing rain fell in valleys of interior Ern ME.  Behind this shortwave, weak backdoor front dropping S thru Ern ME with renewed clouds and temp plateau.  Elsewhere, SW surface flow and assoc mixing doing a good job of breaking up the sky cover, tho where warm and moist advection continue near baroclinic zone aloft I expect clouds to fill back in for most of Nrn NewEng overnight Mon Ngt.

Weak vort lobes ride northeast ahead of strong upper low that is well evidenced on satellite imagery today.  This upper low is largely removed from the westerlies and will be quite slow to progress east.  Though it is packed with tropical moisture, there is no cold air assoc with it.  In fact, there is barely cold left in the lower 48 at all - the coldest of whcih is most certainly over Nrn ME, as Tropical Pacific air floods the Pacific NW.  Water vapor imagery confirms the origin of today's Pacific NW storm, but what is truly remarkable is that surface equivalent potential temperature values of the air in OR, WA and Western MT exceed the warmth and moisture assoc with the sfc reflection of the upper low over Arkansas!  The bottom line is that the lower 48 are being flooded with warm air from all directions today, not to mention moisture input from both the Gulf and the Tropical Pacific.  The leading vort from this Pacific energy arrives on Wed, and have brought in steady precip as a result, esp given that NewEng will remain under low level warm and moist advective regime.  More intense Pacific energy set to arrive on Thu, and this time there is interaction in the midlevels with the upper low off the Carolina coast inputting its Gulf moisture - which more accurately will be a combo of Gulf and Pacific-entrained moisture by that point.  At the surface, large anticyclone shifting off the coast this week remains quite expansive and this cranks up the pressure gradient for a long-fetched SE flow into NewEng on Thu that actually finds its roots at the base of the high - in the Bahamas!  Thus, plenty of moisture to crank out heavy rains both later Wed but moreover Thu as frontal boundary assoc with Pacific short moves sluggishly thru.  Keep in mind the origin of this disturbance from the Tropical Pacific, and there will not be a hearty shot of cold behind it - cool, perhaps, drawn south from the Nrn surface reflection in SE Canada, but not cold, and not long-lasting.  In fact, a heartier shot of cool air would be more likely on Sunday after the passage of a colder shortwave ejected from the Aleutian low, that will carry a pool of shallow cool from Wrn Canada on its trek east.

Thereafter, mild air rules the roost again next week until Aleutian low and Greenland ridge both re-establish, allowing cooler than normal pattern to return with longwave trof eastward migration around the 18th.

Have a great Monday.

Matt

MILD STRETCH TO CONTINUE THROUGH FIRST HALF OF THE WEEKEND

Welcome to the weather blog - a regular Monday through Friday discussion of the weather!  While the discussions usually will only come on days I'm working, I'll issue special updates when the weather warrants.  I will always post to let you know when no discussion is expected if I'm away on vacation, etc. - if no update is here and no info is available, that likely means the server has temporarily gone on the fritz and I will update as soon as technically possible.  You'll find a quick weather synopsis linked to the daily forecast at the top of the page, a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow by mid-afternoon. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

General Weather Summary:

Relatively mild air remains in place across New England, even though winds have shifted to blow from the northwest.  The passage of a storm southeast of New England brought over three inches of rain to Southwest Connecticut and also to the New Hampshire and Southern Maine coastlines, with one to two inches of rain in many other areas.

With the rain exiting New England - lingering as a few stubborn bands across Central and Eastern Maine - moisture was left lingering in the lowest few thousand feet of the atmosphere Thursday morning, meaning lots of low altitude clouds and some drizzle began the day in higher terrain, and in Eastern areas.  As the day progresses, though, the light northwest wind slopes down the hills and mountains of Northern New England, helping to mix the atmosphere by bringing dry air from aloft closer to the ground, evaporating some of the cloud cover and allowing increasing sunshine to emerge.  This trend has continued across most of Western, Central and Southern New England and emerging sun will do its part in pushing an already mild airmass well into the 60s, with some areas surpassing 70 degrees Thursday afternoon, especially in the Lower Connecticut and Pioneer Valleys!

So where is the colder air?  Most of it is locked in Canada, where daily high temperatures were held in the single digits across the Northwest and Western Provinces on Wednesday.  Cooler air - though not deep cold - has been seeping southeast across Central Canada, but even Wednesday night low temperatures in Ontario were mostly in the upper 30s to lower 40s.  So, with the approach of a cool front late Thursday - driven by a jet stream disturbance of moderate strength aloft - there won't be a slug of cold unloading on New England.  Instead, a shower or thunderstorm is possible in Western New England (especially VT and Western MA) Thursday evening, followed by an otherwise dry frontal passage that will increase winds for many areas.  This freshened wind will hold temperatures in the upper 30s to 40s for most of us here in New England, as well, Thursday night.

The new airmass in place on Friday will be dry, and though it will be cooler, we'll still find maximum temperatures above normal for the date with an active westerly breeze sloping down off the hilly terrain of Western New England, helping to nudge most temperatures in Central and Eastern New England to near 60 degrees.  Though this bubble of cool and dry air will allow for temperatures to fall Friday night, yielding a cool start Saturday morning, sunshine should be able to assist in a rebound to start the weekend.  This comes as a new, very strong disturbance dives into the Ohio Valley on Saturday, spawning a storm center to our west.  The counter-clockwise flow of air around this storm will mean a strengthening south and southeast flow of air through the day Saturday, and the key here is just how quickly the warmth comes rushing in.  If it charges at New England early enough Saturday, clouds will move in and be very difficult to break up.  My thinking right now, however, is that some sun comes out early Saturday, and we see intervals of clouds and sun through the day.  By Saturday night, the passage of the strong disturbance aloft, and the cold front it will be dragging, will produce downpours and perhaps a thunderstorm overnight, ushering in a shot of chilly air for Sunday.  For most, Sunday will be a brisk and somewhat blustery day with an active west wind, but mostly just scattered showers.  In the Northern Mountains, however, a northwest wind is likely to induce snow squalls for some of the north facing mountainous terrain.

Cool air will linger into Monday before a return of milder air for midweek that will likely be accompanied by another surge of tropical moisture with a developing storm destined to deliver a bit longer, heartier shot of cold air.

Technical Discussion:  None today.

Matt

Matt's Technical Meteorological Discussion:  Updated Wednesday, November 8 at 3:05 PM

Well defined packet of tropical moisture streaming N up seaboard today is focused N of sfc low center and upper low.  Still a surface/llvl thermal and isodrosothermal (dewpoint) boundary stretched across Central NewEng to the coastal plain of ME and this will continue to focus heavy rains from Hudson Valley thru Wrn MA to ME coast with heavy rains SE of that boundary, as well, and sharply lesser amounts farther northwest.  FFG values 2-3" and this may cause a problem in Srn CT where flood watch is up, as well as Southern to Midcoast ME.  SE wind will freshen ahead of sfc low pressure passage as it moves SE of NewEng and brief gusts 30-40 mph are possible Cape Cod this eve.

Behind this storm, wind shifts to NW, but no immediate cold air source is present, so this leaves a weakly downsloping flow with mild air to the tune of +10 C at 850 mb and +12 to +14 C at 925 mb.  Subsidence sets in during the heart of the day, and this should be sufficient to poke holes in the OVC that will allow for rather rapid temp rises in warm airmass, climbing into the 60s many areas.  Pioneer Valley and perhaps Boston area both stand a shot at 70 with downsloping/sun combo, depending on how much insolation we see.  Have held chc thunder only for Wrn NewEng, as best chance is across NY State where strong diffluence and PVA comes thru during diurnal htg, not arriving into Wrn NewEng until eve, but strong enuf diffluence above warm enuf air to warrant downpour/thunder in the fcst.

This sfc cold front will be progressive, but while air behind it is noteably colder, that's not saying much when you're starting out so anomalously warm, and thermal profile with good mixing and downsloping flow Fri still supports an average high just over 60 with favored downslope areas warmer still.  Have continued to hedge way above MOS for Sat as operational guidance suggests a relatively clean warm sector with possible contamination above 400 mb, but strong thermal advection on Sat.  There are two concerns with this gamble: 1) Southeast sfc flow as low strengthens and doesn't track quite far enuf north to guarantee S or SW flow, meaning tendency is there for an onshore component, and that's frankly why I've gone mid 60s and not closer to 70.  2) Increased llvl moisture thanks to this onshore component.  If that happens, going to have to slice and dice my temps.

Looks like cyclogenesis will occur overhead on Sun as anafront becomes active with wave, and wave will intensify over Ern NewEng.  Still timing diffs on this, but GFS Ensemble is progressive, Canadian and its Ensembles quite slow, and ECMWF seems a good compromise, but leaves Neweng quite windy, chilly and showery on Sun...tho not cold enuf for wintry precip.  Quick shot of cold behind this system for early in the week gives way to more mild anomaly before a rainstorm Thu with good tropical moisture tap again gives way to slug of anomalous cold for a few days.  The warmer than normal pattern returns thereafter, however, with little available deep cold making it into the lower latitudes...for now.

Matt

Monday's Discussion:

1:35 PM:  Early AM shortwave brought new snow to Nrn and Central ME while freezing rain fell in valleys of interior Ern ME.  Behind this shortwave, weak backdoor front dropping S thru Ern ME with renewed clouds and temp plateau.  Elsewhere, SW surface flow and assoc mixing doing a good job of breaking up the sky cover, tho where warm and moist advection continue near baroclinic zone aloft I expect clouds to fill back in for most of Nrn NewEng overnight Mon Ngt.

Weak vort lobes ride northeast ahead of strong upper low that is well evidenced on satellite imagery today.  This upper low is largely removed from the westerlies and will be quite slow to progress east.  Though it is packed with tropical moisture, there is no cold air assoc with it.  In fact, there is barely cold left in the lower 48 at all - the coldest of whcih is most certainly over Nrn ME, as Tropical Pacific air floods the Pacific NW.  Water vapor imagery confirms the origin of today's Pacific NW storm, but what is truly remarkable is that surface equivalent potential temperature values of the air in OR, WA and Western MT exceed the warmth and moisture assoc with the sfc reflection of the upper low over Arkansas!  The bottom line is that the lower 48 are being flooded with warm air from all directions today, not to mention moisture input from both the Gulf and the Tropical Pacific.  The leading vort from this Pacific energy arrives on Wed, and have brought in steady precip as a result, esp given that NewEng will remain under low level warm and moist advective regime.  More intense Pacific energy set to arrive on Thu, and this time there is interaction in the midlevels with the upper low off the Carolina coast inputting its Gulf moisture - which more accurately will be a combo of Gulf and Pacific-entrained moisture by that point.  At the surface, large anticyclone shifting off the coast this week remains quite expansive and this cranks up the pressure gradient for a long-fetched SE flow into NewEng on Thu that actually finds its roots at the base of the high - in the Bahamas!  Thus, plenty of moisture to crank out heavy rains both later Wed but moreover Thu as frontal boundary assoc with Pacific short moves sluggishly thru.  Keep in mind the origin of this disturbance from the Tropical Pacific, and there will not be a hearty shot of cold behind it - cool, perhaps, drawn south from the Nrn surface reflection in SE Canada, but not cold, and not long-lasting.  In fact, a heartier shot of cool air would be more likely on Sunday after the passage of a colder shortwave ejected from the Aleutian low, that will carry a pool of shallow cool from Wrn Canada on its trek east.

Thereafter, mild air rules the roost again next week until Aleutian low and Greenland ridge both re-establish, allowing cooler than normal pattern to return with longwave trof eastward migration around the 18th.

Have a great Monday.

Matt

SHOT OF HEAVY RAIN WEDNESDAY NIGHT TO BE FOLLOWED BY STRETCH OF MILD DAYS

Welcome to the weather blog - a regular Monday through Friday discussion of the weather!  While the discussions usually will only come on days I'm working, I'll issue special updates when the weather warrants.  I will always post to let you know when no discussion is expected if I'm away on vacation, etc. - if no update is here and no info is available, that likely means the server has temporarily gone on the fritz and I will update as soon as technically possible.  You'll find a quick weather synopsis linked to the daily forecast at the top of the page, a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow by mid-afternoon. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

General Weather Summary:

Tropical moisture continues to feed up the Eastern Seaboard on Wednesday, and this will promote periods of rain across New England through the day, with the heaviest rain arriving Wednesday evening and night as the storm center focusing this moisture moves northeast from the Carolinas, passing just southeast of New England.  This pattern of tapping tropical moisture from the Pacific, the Gulf of Mexico and the Bahamas has been a recurrent pattern since over a year ago - not persistent, but recurrent, and once again some flooding may result, though localized in nature.

Big puddles posed hydroplaning concerns for commuters Wednesday morning were the result of overnight rains, sparked by an influx of tropical warmth and moisture several thousand feet in altitude.  Ahead of the approaching storm center, this warmer and more moist air will continue to breed bands of rain - light to moderate through most of Wednesday with elements of heavier downpours from time to time - and the periodic rain will be accompanied by increasingly warm and moist air streaming in at the surface on a southeast wind.  The clash of airmasses through interior New England and along the New Hampshire and Maine seacoasts has already resulted in areas of dense fog, and some of this fog will persist for a few hours, slowing travel.  As the approaching storm center focuses moisture into New England late in the day, rain will become heavier and the evening commute will be slowed for parts of Southern New England.

In addition to heavier rains, wind will crank up briefly along the coast of Cape Cod, where gusts to 30 or even 40 mph are possible late in the afternoon into the evening.  These winds wouldn't be enough to cause damage, but certainly will kick up the surf.  With locally more than two inches of rain falling over Southern Connecticut Tuesday night, localized flooding is possible in these areas, with around an inch of water falling in most of the remainder of Southern New England, one to two inches from the Southern coast of Maine to the Eastern coast, respectively, and markedly less farther north and northwest.

Although winds will blow from the northwest on Thursday, the air will be quite mild with any deeper source of cool air much farther northwest, across Ontario.  This means any breaks of sun after tapering morning showers will really go a long way to boost temperatures, with many spots in Southern New England into the 60s, and a few spots around the Pioneer Valley possibly hitting 70 if enough breaks of sunshine emerge.  A cold front will be waiting in the wings, however, and as it approaches New England later Thursday, may touch off a few downpours or a thunderstorm, especially in Western New England.  Behind this front, drier and not much colder air moves back into New England on Friday.  A new jet stream disturbance will move quickly toward New England heading into Saturday, but indications are that this jet stream disturbance will slow upon arrival, allowing mild air to move back into New England Saturday, then this disturbance may carry a slowing cold front and storm center directly over New England Saturday night and Sunday, bringing rain showers to the six-state region.  Given the fact that this disturbance will be slowing near or over us, colder air will gradually be pulled into the system, and a gusty, chilly wind is likely amidst showers and perhaps some steadier rain on Sunday.  This quick shot of cool air would not be intense, nor long-lived, and the milder pattern resumes ahead of a more permanent cool regime around the end of next week.

Have a wonderful Wednesday.

Matt

Matt's Technical Meteorological Discussion:  Updated Wednesday, November 8 at 3:05 PM

Well defined packet of tropical moisture streaming N up seaboard today is focused N of sfc low center and upper low.  Still a surface/llvl thermal and isodrosothermal (dewpoint) boundary stretched across Central NewEng to the coastal plain of ME and this will continue to focus heavy rains from Hudson Valley thru Wrn MA to ME coast with heavy rains SE of that boundary, as well, and sharply lesser amounts farther northwest.  FFG values 2-3" and this may cause a problem in Srn CT where flood watch is up, as well as Southern to Midcoast ME.  SE wind will freshen ahead of sfc low pressure passage as it moves SE of NewEng and brief gusts 30-40 mph are possible Cape Cod this eve.

Behind this storm, wind shifts to NW, but no immediate cold air source is present, so this leaves a weakly downsloping flow with mild air to the tune of +10 C at 850 mb and +12 to +14 C at 925 mb.  Subsidence sets in during the heart of the day, and this should be sufficient to poke holes in the OVC that will allow for rather rapid temp rises in warm airmass, climbing into the 60s many areas.  Pioneer Valley and perhaps Boston area both stand a shot at 70 with downsloping/sun combo, depending on how much insolation we see.  Have held chc thunder only for Wrn NewEng, as best chance is across NY State where strong diffluence and PVA comes thru during diurnal htg, not arriving into Wrn NewEng until eve, but strong enuf diffluence above warm enuf air to warrant downpour/thunder in the fcst.

This sfc cold front will be progressive, but while air behind it is noteably colder, that's not saying much when you're starting out so anomalously warm, and thermal profile with good mixing and downsloping flow Fri still supports an average high just over 60 with favored downslope areas warmer still.  Have continued to hedge way above MOS for Sat as operational guidance suggests a relatively clean warm sector with possible contamination above 400 mb, but strong thermal advection on Sat.  There are two concerns with this gamble: 1) Southeast sfc flow as low strengthens and doesn't track quite far enuf north to guarantee S or SW flow, meaning tendency is there for an onshore component, and that's frankly why I've gone mid 60s and not closer to 70.  2) Increased llvl moisture thanks to this onshore component.  If that happens, going to have to slice and dice my temps.

Looks like cyclogenesis will occur overhead on Sun as anafront becomes active with wave, and wave will intensify over Ern NewEng.  Still timing diffs on this, but GFS Ensemble is progressive, Canadian and its Ensembles quite slow, and ECMWF seems a good compromise, but leaves Neweng quite windy, chilly and showery on Sun...tho not cold enuf for wintry precip.  Quick shot of cold behind this system for early in the week gives way to more mild anomaly before a rainstorm Thu with good tropical moisture tap again gives way to slug of anomalous cold for a few days.  The warmer than normal pattern returns thereafter, however, with little available deep cold making it into the lower latitudes...for now.

Matt

Monday's Discussion:

1:35 PM:  Early AM shortwave brought new snow to Nrn and Central ME while freezing rain fell in valleys of interior Ern ME.  Behind this shortwave, weak backdoor front dropping S thru Ern ME with renewed clouds and temp plateau.  Elsewhere, SW surface flow and assoc mixing doing a good job of breaking up the sky cover, tho where warm and moist advection continue near baroclinic zone aloft I expect clouds to fill back in for most of Nrn NewEng overnight Mon Ngt.

Weak vort lobes ride northeast ahead of strong upper low that is well evidenced on satellite imagery today.  This upper low is largely removed from the westerlies and will be quite slow to progress east.  Though it is packed with tropical moisture, there is no cold air assoc with it.  In fact, there is barely cold left in the lower 48 at all - the coldest of whcih is most certainly over Nrn ME, as Tropical Pacific air floods the Pacific NW.  Water vapor imagery confirms the origin of today's Pacific NW storm, but what is truly remarkable is that surface equivalent potential temperature values of the air in OR, WA and Western MT exceed the warmth and moisture assoc with the sfc reflection of the upper low over Arkansas!  The bottom line is that the lower 48 are being flooded with warm air from all directions today, not to mention moisture input from both the Gulf and the Tropical Pacific.  The leading vort from this Pacific energy arrives on Wed, and have brought in steady precip as a result, esp given that NewEng will remain under low level warm and moist advective regime.  More intense Pacific energy set to arrive on Thu, and this time there is interaction in the midlevels with the upper low off the Carolina coast inputting its Gulf moisture - which more accurately will be a combo of Gulf and Pacific-entrained moisture by that point.  At the surface, large anticyclone shifting off the coast this week remains quite expansive and this cranks up the pressure gradient for a long-fetched SE flow into NewEng on Thu that actually finds its roots at the base of the high - in the Bahamas!  Thus, plenty of moisture to crank out heavy rains both later Wed but moreover Thu as frontal boundary assoc with Pacific short moves sluggishly thru.  Keep in mind the origin of this disturbance from the Tropical Pacific, and there will not be a hearty shot of cold behind it - cool, perhaps, drawn south from the Nrn surface reflection in SE Canada, but not cold, and not long-lasting.  In fact, a heartier shot of cool air would be more likely on Sunday after the passage of a colder shortwave ejected from the Aleutian low, that will carry a pool of shallow cool from Wrn Canada on its trek east.

Thereafter, mild air rules the roost again next week until Aleutian low and Greenland ridge both re-establish, allowing cooler than normal pattern to return with longwave trof eastward migration around the 18th.

Have a great Monday.

Matt

MOST AREAS ENJOY DRY THOUGH CLOUDY ELECTION DAY...BUT WINDS OF CHANGE SWEEP ACROSS MORE THAN POLITICS

Welcome to the weather blog - a regular Monday through Friday discussion of the weather!  While the discussions usually will only come on days I'm working, I'll issue special updates when the weather warrants.  I will always post to let you know when no discussion is expected if I'm away on vacation, etc. - if no update is here and no info is available, that likely means the server has temporarily gone on the fritz and I will update as soon as technically possible.  You'll find a quick weather synopsis linked to the daily forecast at the top of the page, a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow by mid-afternoon. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

General Weather Summary:

The veil of clouds across New England Tuesday represents warmth and moisture streaming overhead - an indication that the awaited transition to milder times is well underway.  This transition will continue as the jet stream - the fast river of air aloft that steers our storm systems and acts as a thermostat, separating cold to the north from warmth to the south - moves northward over New England.  This shift comes as the jet stream undergoes a process known as "retrogression" - that is, moving backwards - as the trough of cold air that's been over us for the past few weeks moves to the west while retreating into Canada, and a ridge of warmth replaces it.

Our Tuesday weather map shows an expansive high pressure cell - a fair weather center - moving east off the Atlantic Seaboard.  The clockwise flow of air around this high pressure cell is ushering a south-southwest wind into New England at the surface, continuing the feed of warmth to the six-state region.  Remember that warm air is less dense than cold air and rises, which means this incoming warmth has been riding up and over our cool dome Monday night into early Tuesday, which is why we've been seeing high and middle altitude clouds.  Closer to ground level, it takes awhile longer to erode the cool air, but even with filtered and dimmed sunshine through thickening clouds, milder air will make inroads at the surface, and temperatures will respond.  As for rainfall, our dry airmass will evaporate most raindrops as they fall from the clouds Tuesday afternoon, but by early evening a few light showers may fall - likely to be rather isolated in coverage and quite light in nature, and posing no significant impediment to getting out the vote!

As our blanket of clouds increases Tuesday night, expect temperatures to remain rather mild across New England, with rain developing after polls close in most areas - especially after 9 or 10 PM - and lasting into early Wednesday morning.  This rain will be the result of a slug of warmer and more moist air moving into New England, and as the leading edge to this warmth and moisture moves through, the rain will remain progressive, as well, dropping only about .25"-.50" and allowing for a break in the action most of the day Wednesday after lingering showers early.

Meanwhile, the storm that's been moving across the Southeastern United States Monday and Tuesday is nearing the coastline.  This storm was already loaded with moisture - infused with Gulf of Mexico moisture that it continues to tap through Tuesday, but now we're seeing the anticipated influx of moisture from the Bahamas and Tropical Atlantic, too, which will further enhance the efficiency of rainfall production with this storm.  Though it does not appear as though the entirety of this storm will turn north into New England, the sluggish departure of high pressure off the coastline will slow this system enough that by later Wednesday into Thursday it will interact with the northern flow of jet stream disturbances moving over New England.  This interaction, combined with our continued surface flow of mild and moist air, will mean enhanced rainfall across New England later Wednesday into the first half of Thursday, falling heavily at times but also accompanied by relatively mild air and gusty coastal winds, especiallly in Southern New England.  Of course, with warmth and water comes at least a minor disruption and headache for ski areas that have been cranking out snow and developing a solid base, as there will be at least some nights in the coming stretch that will be too warm for snowmaking, though I can assure you there will also be shots of air plenty cold enough to add to the base, so expect sporadic conditions the next several nights.

A cold front will have to pass through New England later Thursday, and may be accompanied by a round of downpours and thunder, before drier air moves back into New England on Friday.  A new jet stream disturbance will move quickly toward New England heading into Saturday, but indications are that this jet stream disturbance will slow upon arrival, allowing mild air to move back into New England for a time on Saturday, then this disturbance may carry a slowing cold front and storm center directly over New England Saturday night and Sunday, bringing rain showers to the six-state region.  Given the fact that this disturbance will be slowing near or over us, there is still some room for error here, and I'll continue to follow it for you.  Regardless, a quick shot of cool air would come in behind the storm for early next week before the milder pattern resumes ahead of a more permanent cool regime around the end of next week.

Now, go vote! :)

No techie discussion today.

Matt

Matt's Technical Meteorological Discussion:  Updated Monday, November 6 at 1:35 PM

Early AM shortwave brought new snow to Nrn and Central ME while freezing rain fell in valleys of interior Ern ME.  Behind this shortwave, weak backdoor front dropping S thru Ern ME with renewed clouds and temp plateau.  Elsewhere, SW surface flow and assoc mixing doing a good job of breaking up the sky cover, tho where warm and moist advection continue near baroclinic zone aloft I expect clouds to fill back in for most of Nrn NewEng overnight Mon Ngt.

Weak vort lobes ride northeast ahead of strong upper low that is well evidenced on satellite imagery today.  This upper low is largely removed from the westerlies and will be quite slow to progress east.  Though it is packed with tropical moisture, there is no cold air assoc with it.  In fact, there is barely cold left in the lower 48 at all - the coldest of whcih is most certainly over Nrn ME, as Tropical Pacific air floods the Pacific NW.  Water vapor imagery confirms the origin of today's Pacific NW storm, but what is truly remarkable is that surface equivalent potential temperature values of the air in OR, WA and Western MT exceed the warmth and moisture assoc with the sfc reflection of the upper low over Arkansas!  The bottom line is that the lower 48 are being flooded with warm air from all directions today, not to mention moisture input from both the Gulf and the Tropical Pacific.  The leading vort from this Pacific energy arrives on Wed, and have brought in steady precip as a result, esp given that NewEng will remain under low level warm and moist advective regime.  More intense Pacific energy set to arrive on Thu, and this time there is interaction in the midlevels with the upper low off the Carolina coast inputting its Gulf moisture - which more accurately will be a combo of Gulf and Pacific-entrained moisture by that point.  At the surface, large anticyclone shifting off the coast this week remains quite expansive and this cranks up the pressure gradient for a long-fetched SE flow into NewEng on Thu that actually finds its roots at the base of the high - in the Bahamas!  Thus, plenty of moisture to crank out heavy rains both later Wed but moreover Thu as frontal boundary assoc with Pacific short moves sluggishly thru.  Keep in mind the origin of this disturbance from the Tropical Pacific, and there will not be a hearty shot of cold behind it - cool, perhaps, drawn south from the Nrn surface reflection in SE Canada, but not cold, and not long-lasting.  In fact, a heartier shot of cool air would be more likely on Sunday after the passage of a colder shortwave ejected from the Aleutian low, that will carry a pool of shallow cool from Wrn Canada on its trek east.

Thereafter, mild air rules the roost again next week until Aleutian low and Greenland ridge both re-establish, allowing cooler than normal pattern to return with longwave trof eastward migration around the 18th.

Have a great Monday.

Matt

WEATHER PATTERN SHIFT UNDERWAY...MILDER TEMPERATURES TO RULE OVERALL NEXT TWO WEEKS

Welcome to the weather blog - a regular Monday through Friday discussion of the weather!  While the discussions usually will only come on days I'm working, I'll issue special updates when the weather warrants.  I will always post to let you know when no discussion is expected if I'm away on vacation, etc. - if no update is here and no info is available, that likely means the server has temporarily gone on the fritz and I will update as soon as technically possible.  You'll find a quick weather synopsis linked to the daily forecast at the top of the page, a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow by mid-afternoon. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

General Weather Summary:

The promised transition from below to above normal average temperatures in New England is underway this Monday.  This change comes as the jet stream - the fast river of air aloft that steers our storm systems and acts as a thermostat, separating cold to the north from warmth to the south - moves northward over New England.  This shift comes as the jet stream undergoes a process known as "retrogression" - that is, moving backwards - as the trough of cold air that's been over us for the past few weeks moves to the west, and a ridge of warmth replaces it.

As we begin what will be an above-normal week for average temperature, a southwest flow has already begun in the atmosphere, but the collision of our lingering cold and incoming warmth is a bumpy one in some spots - specifically in Maine, where the day began with a couple of new inches of snow in Northern and North-Central Maine, and pockets of valley freezing rain in interior Eastern Maine.  This wintry start represents the cool side of a battle of airmasses, with Monday morning clouds extending as far south as the Southern Massachusetts state line with Connecticut and Rhode Island.

The combination of drier air and a southwest flow will help to break clouds apart in Central and Southern New England as Monday wears on.  This comes, of course, partly because drier air will help to evaporate the clouds, but more importantly because a southwest wind near the surface will slope down some of our hills like the Worcester Hills, Berkshires, Monadnock Region and Litchfield Hills, helping to mix the drier air into the atmosphere and favor at least breaks between clouds.  Farther north and east, deeper into the cold air...it will be harder to break the clouds apart, but wintry precipitation will draw to a close by midday Monday as the upper level jet stream disturbance responsible for the mix departs to the east.  Under the lingering clouds, temperatures will remain cool, while those areas that break into some sunshine will find milder conditions.

Monday night will bring a similar dichotomy from northeast to southwest, as somewhat milder air will be in place thousands of feet above the heads of Southern New Englanders, allowing skies to remain partly cloudy through the night, while most of Northern New England will still be under the battle of airmasses, holding clouds tight across the area through Monday night.  By Tuesday, early sunshine in parts of Southern New England will fade as clouds thicken for one and all through the day, a product of increasing moisture in a strengthening southwest flow behind a departing high pressure cell.  This southerly flow will transport moisture northward through the lowest 10,000 feet of the atmosphere Tuesday afternoon, and this may produce at least a few showers across Southern New England late in the afternoon into election evening.  While this isn't the news election folks like to hear, the important point to drive home is that these showers will be very few and far between, and quite light, meaning effects on voter turnout should be negligible.

Meanwhile, a storm that's located over Arkansas as of this writing early Monday holds a great deal of tropical moisture and plenty of energy aloft.  This slow-moving storm is quite dynamic, and will carry thunderstorms and heavy rains across the Southeastern United States through the first half of the week.  Though it does not appear as though the entirety of this storm will turn north into New England, the sluggish departure of high pressure off the coastline will slow this system enough that by later Wednesday into Thursday it's likely to at least interact with the northern flow of jet stream disturbances moving over New England.  This interaction, combined with our continued surface flow of mild and moist air, will mean enhanced rainfall across New England later Wednesday into the first half of Thursday, falling heavily at times but also accompanied by relatively mild air, especiallly prior to the arrival of rainfall later Wednesday.  Of course, with warmth and water comes at least a minor disruption and headache for ski areas that have been cranking out snow and developing a solid base, as there will be at least some nights in the coming stretch that will be too warm for snowmaking, though I can assure you there will also be shots of air plenty cold enough to add to the base, so expect sporadic conditions the next several nights.

By later Thursday into Friday, drier air should move back into New England, before a renewed chance of showers with the passage of a cold front on Saturday, and a brief shot of cooler air behind it for the end of the weekend.  Milder than normal temperatures will return next week, until another shift in the jet stream will redirect colder air toward New England somewhere around November 17-19.

Have a great Monday!

Matt

Matt's Technical Meteorological Discussion:  Updated Monday, November 6 at 1:35 PM

Early AM shortwave brought new snow to Nrn and Central ME while freezing rain fell in valleys of interior Ern ME.  Behind this shortwave, weak backdoor front dropping S thru Ern ME with renewed clouds and temp plateau.  Elsewhere, SW surface flow and assoc mixing doing a good job of breaking up the sky cover, tho where warm and moist advection continue near baroclinic zone aloft I expect clouds to fill back in for most of Nrn NewEng overnight Mon Ngt.

Weak vort lobes ride northeast ahead of strong upper low that is well evidenced on satellite imagery today.  This upper low is largely removed from the westerlies and will be quite slow to progress east.  Though it is packed with tropical moisture, there is no cold air assoc with it.  In fact, there is barely cold left in the lower 48 at all - the coldest of whcih is most certainly over Nrn ME, as Tropical Pacific air floods the Pacific NW.  Water vapor imagery confirms the origin of today's Pacific NW storm, but what is truly remarkable is that surface equivalent potential temperature values of the air in OR, WA and Western MT exceed the warmth and moisture assoc with the sfc reflection of the upper low over Arkansas!  The bottom line is that the lower 48 are being flooded with warm air from all directions today, not to mention moisture input from both the Gulf and the Tropical Pacific.  The leading vort from this Pacific energy arrives on Wed, and have brought in steady precip as a result, esp given that NewEng will remain under low level warm and moist advective regime.  More intense Pacific energy set to arrive on Thu, and this time there is interaction in the midlevels with the upper low off the Carolina coast inputting its Gulf moisture - which more accurately will be a combo of Gulf and Pacific-entrained moisture by that point.  At the surface, large anticyclone shifting off the coast this week remains quite expansive and this cranks up the pressure gradient for a long-fetched SE flow into NewEng on Thu that actually finds its roots at the base of the high - in the Bahamas!  Thus, plenty of moisture to crank out heavy rains both later Wed but moreover Thu as frontal boundary assoc with Pacific short moves sluggishly thru.  Keep in mind the origin of this disturbance from the Tropical Pacific, and there will not be a hearty shot of cold behind it - cool, perhaps, drawn south from the Nrn surface reflection in SE Canada, but not cold, and not long-lasting.  In fact, a heartier shot of cool air would be more likely on Sunday after the passage of a colder shortwave ejected from the Aleutian low, that will carry a pool of shallow cool from Wrn Canada on its trek east.

Thereafter, mild air rules the roost again next week until Aleutian low and Greenland ridge both re-establish, allowing cooler than normal pattern to return with longwave trof eastward migration around the 18th.

Have a great Monday.

Matt

BRISK WEEKEND TO GIVE WAY TO WARMING TREND

Welcome to the weather blog - a regular Monday through Friday discussion of the weather!  While the discussions usually will only come on days I'm working, I'll issue special updates when the weather warrants.  I will always post to let you know when no discussion is expected if I'm away on vacation, etc. - if no update is here and no info is available, that likely means the server has temporarily gone on the fritz and I will update as soon as technically possible.  You'll find a quick weather synopsis linked to the daily forecast at the top of the page, a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow by mid-afternoon. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

General Weather Summary:

Relatively light winds, mostly clear skies, and a chilly Canadian airmass allowed temperatures to fall below freezing in most areas before dawn Friday morning, with some exceptions.  The pattern of cold nights and brisk days will continue through the weekend as an expansive area of high pressure moves slowly south of New England, with its clockwise flow keeping a cool northwest wind in place through the weekend.

Though breezes ahead of this building high pressure center won't be all that impressive on Friday, certainly those who work outside will feel a noticeable chill to the air with the combination of maximum temperatures in the 40s and a steady northwest wind at 5-15 mph adding the additional chill factor.

As for our overall weather pattern, the jet stream winds aloft - the fast winds high in the sky that steer our storm systems and act as a thermostat for the atmosphere, separating cold to the north from warm to the south - dip over New England, forming what's called a "trough" in the world of meteorology.  This trough will lock in through the weekend, keeping cold air in place.  As the cold air charges east across the Great Lakes into Saturday, bands of lake-effect snow will result, feeding off the difference in temperature between the cold air, and the relatively warm lake waters.  Off Lake Ontario, this band of snow will extend across Northern New York State, launching scattered snow showers into the Green Mountains later Friday through Saturday.  At the same time, weak disturbances will ride through the jet stream, dipping over New England through the weekend and perhaps delivering a few flurries and snow showers to the remainder of the Northern Mountains, though for most areas the air will be dry enough to preclude any precipitation.

Even by later Sunday, as warmer air and increased moisture will attempt a return to New England ahead of a disturbance pushing east out of the Rocky Mountains, our bubble of high pressure and dry air is likely to weaken any shield of precipitation significantly, and keep it moving slowly enough to keep Sunday mostly dry.  By Sunday evening and night, a slight chance of some light rain or snow would be possible with the increase in moisture aloft, but the dry nature of our near-ground air keeps this chance quite minimal.  Periods of clouds may continue from time to time on Monday, as well, as the deep cold lets go of New England.  This time, however, the deep cold won't be letting go for only a day or two, as a change to the jet stream pattern will shift our trough out west, meaning temperatures should come near normal then above normal on average through an extended stretch through the middle of November.

Have a wonderful weekend!

Technical Discussion:  With not much weather in the offing, and an exceptional load behind the scenes, only the one techie discussion this week.  Next week should bring more active weather, and therefore more technical write-ups.

Matt

Matt's Technical Meteorological Discussion:  Updated Monday, October 30 at 2:30 PM

Relatively quiet in the short term as winds subside this eve with decreasing PG - but only briefly as strong SW gradient has established over OH Valley.  Air advecting thru the boundary layer toward NewEng has history of 60s and 70s and will be in place Tue, tho with shifting winds slackening under sfc ridge axis overnight, expect valleys to decouple with frost while most areas land in the 20s and 30s, esp given that Tds currently running in low to mid 20s.  Cold start Tue to be moderated by aforementioned SW flow and help from insolation.  Full insolation with 925 mb temps would support temps over 70 in Srn NewEng, but decent moisture connection already evident on satellite imagery today over the Central and South-Central US is well modeled and progged to move overhead on Tue, limiting insolation by at least filtering sun.  Mixing will be a bit limited thanks to this cloud cover, and coupled with cold start, temps shud land in mid 60s most areas of Central/Srn NewEng...tho CT river valley may be able to hit 70.  This will leave a mild eve for trick-or-treating as mild flow continues in advance of shortwave moving east across the Nrn Plains as of this writing, and that will be moving thru Srn Canada on Tue.

Xpct showers Tue ngt - after 00Z - that will amount to between .01 and .15" of QPF (perhaps a bit higher in upslope favored areas) as low level moisture feed will have trouble establishing into such a dry antecedent airmass.  Air will be warm enough for rain all areas with plenty of warmth aloft.  Colder installments thru the end of the week with next shortwave slated for later Fri with chc showers from NW to SE later in the day, ushering in next fortified shot of chill in a steadily declining temp regime into the weekend.

The longwave pattern will actually favor recoiling heights northward quickly behind the shortwave on Fri as Srn Canada upper low is absorbed into deepening very strong polar vortex near the pole.  But left behind in fast westerly flow will be new energy ejecting from the Aleutian low, and this will help to maintain cool flow sfc and aloft into New Eng until these cold shortwaves pass later in the weekend.  Thereafter, strong Pacific energy will be trying to close off briefly over the Midwest, and while it may not live long, it will lower heights enough for energy continuing to shoot east from the strengthening Aleutian low - feeding off southward seeping energy from the polar vortex - into this new developing trough.  This feed of air from polar vortex to Aleutian low to Intermountain region will assist in longwave retrogression, with trough settling to our west, and putting NewEng in developing deep SW flow.  This sets up a pattern that will favor both warmth, and rainfall into NewEng for the first half of November, with the warmth coming on by next Mon/Tue, and the moisture not too far behind - likely a decent rain event MidAtl to Northeast mid to late next week as energy continues to eject from base of new trof, carrying Pacific subtropical moisture and tapping Gulf moisture.  Though this results in building northeast warmth thru the first two weeks of November, winter lovers should not lose hope here, as the retrogression will cease and the weather pattern become a bit more progressive by the latter half of the month, largely thanks to a super-ridge to develop across the Nrn Pacific, eventually dislodging both the energy and cold out of Alaska while NewEng warmth should serve as fuel for pumping heights to our east and building a rather impressive block over Greenland the latter half of the month.

So, in the short term we see cold persisting and in fact providing one of our cooler shots thus far for the upcoming weekend - likely to be accompanied by at least some upslope snows - before we see our pattern shift to warmth, then wet and warm...all perhaps en route to a different second half of November.

In the meantime, ski resorts should be able to take advantage of good snowmaking weather most nights except Tue Ngt of this week, through Mon Ngt of next week.  Make the most of it if you want to get the early start on the season, as you'll need a base that can survive only occasional snowmaking capabilities Nov 7 thru 14.

Matt

COOL AIR MOVING INTO NEW ENGLAND...HERE FOR AN EXTENDED WEEKEND STAY

Welcome to the weather blog - a regular Monday through Friday discussion of the weather!  While the discussions usually will only come on days I'm working, I'll issue special updates when the weather warrants.  I will always post to let you know when no discussion is expected if I'm away on vacation, etc. - if no update is here and no info is available, that likely means the server has temporarily gone on the fritz and I will update as soon as technically possible.  You'll find a quick weather synopsis linked to the daily forecast at the top of the page, a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow by mid-afternoon. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

General Weather Summary:

The snow and rain that began the day across New England on Thursday will remain progressive, exiting most Eastern areas by early afternoon and leaving behind clearing skies from northwest to southeast.  This drier air will also be noticeably cooler air, with some Southeastern New England temperatures actually cooler by afternoon than they were before dawn!  This new air will be the same airmass that will remain in place across New England through the weekend.

These changes come as the jet stream winds aloft - the fast winds high in the sky that steer our storm systems and act as a thermostat for the atmosphere, separating cold to the north from warm to the south - dip over New England, forming what's called a "trough" in the world of meteorology.  This trough will lock in through the weekend, keeping cold air in place.  As the cold air charges east across the Great Lakes through Friday, bands of lake-effect snow will result, feeding off the difference in temperature between the cold air, and the relatively warm lake waters.  Off Lake Ontario, this band of snow will extend across Northern New York State later Friday, launching scattered snow showers into the Green Mountains later Friday through Saturday.

Elsewhere, the results of the incoming cold will be less visible, but certainly tangible!  Low temperatures Thursday night will dip into the 20s and 30s with areas of freezing fog resulting in some black ice for a few areas, and Friday will bring an active breeze as cool air continues to pour in.  This cold airmass is the outer periphery of the air that's been dropping temperatures into the teens the past few mornings in the Midwest, but will spill into New England in significantly modified form.

Most of the weekend appears dry and cool with the exception of the aforementioned Green Mountain snow showers.  By later Sunday, warmer air will attempt a return to New England - likely moving in slowly enough to avoid any precipitation, but providing enough of a temperature clash for clouds to form overhead, especially later in the day.  Periods of clouds may continue from time to time on Monday, as well, as the deep cold lets go of New England.  This time, however, the deep cold won't be letting go for only a day or two, as a change to the jet stream pattern will shift our trough out west, meaning temperatures should come near normal then above normal on average through an extended stretch through the middle of November.

Enjoy the day!

Technical Discussion:  None today.

Matt

Matt's Technical Meteorological Discussion:  Updated Monday, October 30 at 2:30 PM

Relatively quiet in the short term as winds subside this eve with decreasing PG - but only briefly as strong SW gradient has established over OH Valley.  Air advecting thru the boundary layer toward NewEng has history of 60s and 70s and will be in place Tue, tho with shifting winds slackening under sfc ridge axis overnight, expect valleys to decouple with frost while most areas land in the 20s and 30s, esp given that Tds currently running in low to mid 20s.  Cold start Tue to be moderated by aforementioned SW flow and help from insolation.  Full insolation with 925 mb temps would support temps over 70 in Srn NewEng, but decent moisture connection already evident on satellite imagery today over the Central and South-Central US is well modeled and progged to move overhead on Tue, limiting insolation by at least filtering sun.  Mixing will be a bit limited thanks to this cloud cover, and coupled with cold start, temps shud land in mid 60s most areas of Central/Srn NewEng...tho CT river valley may be able to hit 70.  This will leave a mild eve for trick-or-treating as mild flow continues in advance of shortwave moving east across the Nrn Plains as of this writing, and that will be moving thru Srn Canada on Tue.

Xpct showers Tue ngt - after 00Z - that will amount to between .01 and .15" of QPF (perhaps a bit higher in upslope favored areas) as low level moisture feed will have trouble establishing into such a dry antecedent airmass.  Air will be warm enough for rain all areas with plenty of warmth aloft.  Colder installments thru the end of the week with next shortwave slated for later Fri with chc showers from NW to SE later in the day, ushering in next fortified shot of chill in a steadily declining temp regime into the weekend.

The longwave pattern will actually favor recoiling heights northward quickly behind the shortwave on Fri as Srn Canada upper low is absorbed into deepening very strong polar vortex near the pole.  But left behind in fast westerly flow will be new energy ejecting from the Aleutian low, and this will help to maintain cool flow sfc and aloft into New Eng until these cold shortwaves pass later in the weekend.  Thereafter, strong Pacific energy will be trying to close off briefly over the Midwest, and while it may not live long, it will lower heights enough for energy continuing to shoot east from the strengthening Aleutian low - feeding off southward seeping energy from the polar vortex - into this new developing trough.  This feed of air from polar vortex to Aleutian low to Intermountain region will assist in longwave retrogression, with trough settling to our west, and putting NewEng in developing deep SW flow.  This sets up a pattern that will favor both warmth, and rainfall into NewEng for the first half of November, with the warmth coming on by next Mon/Tue, and the moisture not too far behind - likely a decent rain event MidAtl to Northeast mid to late next week as energy continues to eject from base of new trof, carrying Pacific subtropical moisture and tapping Gulf moisture.  Though this results in building northeast warmth thru the first two weeks of November, winter lovers should not lose hope here, as the retrogression will cease and the weather pattern become a bit more progressive by the latter half of the month, largely thanks to a super-ridge to develop across the Nrn Pacific, eventually dislodging both the energy and cold out of Alaska while NewEng warmth should serve as fuel for pumping heights to our east and building a rather impressive block over Greenland the latter half of the month.

So, in the short term we see cold persisting and in fact providing one of our cooler shots thus far for the upcoming weekend - likely to be accompanied by at least some upslope snows - before we see our pattern shift to warmth, then wet and warm...all perhaps en route to a different second half of November.

In the meantime, ski resorts should be able to take advantage of good snowmaking weather most nights except Tue Ngt of this week, through Mon Ngt of next week.  Make the most of it if you want to get the early start on the season, as you'll need a base that can survive only occasional snowmaking capabilities Nov 7 thru 14.

Matt

COOL AIR RIDES SOUTH...MOISTURE RIDES NORTH...TRICKY NEW ENGLAND FORECAST ENSUES FOR SOME ON THURSDAY!

Welcome to the weather blog - a regular Monday through Friday discussion of the weather!  While the discussions usually will only come on days I'm working, I'll issue special updates when the weather warrants.  I will always post to let you know when no discussion is expected if I'm away on vacation, etc. - if no update is here and no info is available, that likely means the server has temporarily gone on the fritz and I will update as soon as technically possible.  You'll find a quick weather synopsis linked to the daily forecast at the top of the page, a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow by mid-afternoon. My email is contact@mattnoyes.net.  This blog is for you, so I hope you enjoy it!  -Matt Noyes

General Weather Summary:

A tenuous forecast lay ahead through Thursday afternoon, as the cold front responsible for Tuesday night and Wednesday morning rains slows and eventually stalls just after clearing Southern New England, serving as a pathway for the next disturbance to travel along.  The tricks come into play with regard to how much cool air settles south into New England, and how far north moisture penetrates.

In the meantime, the front responsible for early Wednesday showers has run into the warmth provided to New England yesterday by the Bermuda high, parked off the coastline.  This flow of warm air has slowed the passage of our cold front considerably, and will stall the front off the Southern New England coastline later Wednesday.  Behind the wind shift associated with the front, however, has come drier air both at the surface and aloft, and this has allowed many clouds to dissipate and sunshine to emerge in most spots.  Dewpoint values - the measure of the amount of moisture in the air - have been dropping steadily with this new airmass moving in, now in the 20s and 30s across most of Central and Southern New England as of this writing.  While drier air has moved south quickly, though, colder air lags behind, and the result is for a rather comfortable, pleasant day with a refreshing breeze for most of New England.

The same cold front stalling off the Southern New England coastline runs all the way through the Eastern United States, draped far enough south and west to reach the Lower Mississippi River Valley, where a new storm center is developing along it.  This new storm will continue riding northeast out of Mississippi and Alabama on Wednesday, scooting quickly along the front and reaching the South Coast of New England by Thursday afternoon.  As this storm focuses moisture and carries it northeast, clouds will thicken across the area overnight Wednesday night, with predawn rain developing in many areas.  Enough cold air will have drained southward out of Southern Canada for snow to fall in the higher terrain of Northern New England Thursday morning, though many lower elevations such as deeper valleys, etc., will begin the day with raindrops, as warmth will be trapped in these valleys overnight Wednesday night with no sharp wind to sweep it out.  Rain will also be the dominant precipitation type farther south through New England.  The subtle but important change through the day, however, will be a strengthening north and northwest wind, that will carry colder air southward and sweep it into even the lower terrain of Northern New England.  The trick here is that a lot of this cold air pours south just as precipitation is shutting down.  In the higher terrain of the Green and White Mountains, and the mountains of Maine, the question revolves more around how much moisture streams north, rather than if it will be cold enough, as increased elevation will provide cold enough air for snowflakes.  At this point, it seems most likely we'll find between two and four new inches of snow in the mountains of the north, with at least some snowflakes as the moisture shuts down in Western MA, Central and parts of Southern NH, and Central ME, late in the day.  As indicated in the map below, a dusting to 1" may accumulate in these areas, though that would likely be rather elevation dependent.  As for where this storm could surprise us:  1) moisture doesn't come as far north as I'm expecting, 2) cold air comes farther south than expected, boosting amounts on the southern fringe of the forecasted accums, especially on hills.  But for now, this is my best estimate.

Behind this disturbance, colder air will move in a bit more forcefully.  Air across the Northern Plains and Midwest produced low temperatures in the teens Wednesday morning, and this air, will move east into New England in much modified form.  Nonetheless, temperatures will be cold enough aloft to initiate a lake-effect band of snow off Lake Ontario Friday, which will spray snow showers into the Green Mountains Friday afternoon while the rest of the mountains also see snow showers due to a strong disturbance aloft.  Elsewhere, Friday is most likely to bring billowing clouds, a few sprinkles or flurries, and a chilly feel.

Expect cool but relatively dry air to last through the weekend before a warmup early next week gives way to what is likely to be an intense rainstorm later in the week.

Make it a great start to November!

Technical Discussion:  Out by early afternoon.

Matt

Matt's Technical Meteorological Discussion:  Updated Monday, October 30 at 2:30 PM

Relatively quiet in the short term as winds subside this eve with decreasing PG - but only briefly as strong SW gradient has established over OH Valley.  Air advecting thru the boundary layer toward NewEng has history of 60s and 70s and will be in place Tue, tho with shifting winds slackening under sfc ridge axis overnight, expect valleys to decouple with frost while most areas land in the 20s and 30s, esp given that Tds currently running in low to mid 20s.  Cold start Tue to be moderated by aforementioned SW flow and help from insolation.  Full insolation with 925 mb temps would support temps over 70 in Srn NewEng, but decent moisture connection already evident on satellite imagery today over the Central and South-Central US is well modeled and progged to move overhead on Tue, limiting insolation by at least filtering sun.  Mixing will be a bit limited thanks to this cloud cover, and coupled with cold start, temps shud land in mid 60s most areas of Central/Srn NewEng...tho CT river valley may be able to hit 70.  This will leave a mild eve for trick-or-treating as mild flow continues in advance of shortwave moving east across the Nrn Plains as of this writing, and that will be moving thru Srn Canada on Tue.

Xpct showers Tue ngt - after 00Z - that will amount to between .01 and .15" of QPF (perhaps a bit higher in upslope favored areas) as low level moisture feed will have trouble establishing into such a dry antecedent airmass.  Air will be warm enough for rain all areas with plenty of warmth aloft.  Colder installments thru the end of the week with next shortwave slated for later Fri with chc showers from NW to SE later in the day, ushering in next fortified shot of chill in a steadily declining temp regime into the weekend.

The longwave pattern will actually favor recoiling heights northward quickly behind the shortwave on Fri as Srn Canada upper low is absorbed into deepening very strong polar vortex near the pole.  But left behind in fast westerly flow will be new energy ejecting from the Aleutian low, and this will help to maintain cool flow sfc and aloft into New Eng until these cold shortwaves pass later in the weekend.  Thereafter, strong Pacific energy will be trying to close off briefly over the Midwest, and while it may not live long, it will lower heights enough for energy continuing to shoot east from the strengthening Aleutian low - feeding off southward seeping energy from the polar vortex - into this new developing trough.  This feed of air from polar vortex to Aleutian low to Intermountain region will assist in longwave retrogression, with trough settling to our west, and putting NewEng in developing deep SW flow.  This sets up a pattern that will favor both warmth, and rainfall into NewEng for the first half of November, with the warmth coming on by next Mon/Tue, and the moisture not too far behind - likely a decent rain event MidAtl to Northeast mid to late next week as energy continues to eject from base of new trof, carrying Pacific subtropical moisture and tapping Gulf moisture.  Though this results in building northeast warmth thru the first two weeks of November, winter lovers should not lose hope here, as the retrogression will cease and the weather pattern become a bit more progressive by the latter half of the month, largely thanks to a super-ridge to develop across the Nrn Pacific, eventually dislodging both the energy and cold out of Alaska while NewEng warmth should serve as fuel for pumping heights to our east and building a rather impressive block over Greenland the latter half of the month.

So, in the short term we see cold persisting and in fact providing one of our cooler shots thus far for the upcoming weekend - likely to be accompanied by at least some upslope snows - before we see our pattern shift to warmth, then wet and warm...all perhaps en route to a different second half of November.

In the meantime, ski resorts should be able to take advantage of good snowmaking weather most nights except Tue Ngt of this week, through Mon Ngt of next week.  Make the most of it if you want to get the early start on the season, as you'll need a base that can survive only occasional snowmaking capabilities Nov 7 thru 14.

Matt