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 and a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow. My email is contact@mattnoyes.net. This blog is for you, so I hope you enjoy it! -Matt Noyes
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Matt's Quick Weather Synopsis: Clouds that have developed across parts of interior New England will melt away quickly Friday morning, allowing plenty of sunshine for all of New England. While that sunshine will resemble yesterday's weather, the feel outside will be quite different for one and all, as new air has moved into New England on northeast and east winds, blowing in cool and crisp air from Canada and off of the cold ocean waters. The result will be widespread high temperatures some 15-20 degrees cooler than Thursday was, especiallly for interior New England! The air is as dry as it is cool, and fire danger remains high across New England - especially NH and ME. Expect a chilly night under mostly clear skies Friday night with deeper valleys seeing some fog, and cool, dry conditions will prevail on Saturday for most of New England as well. A storm approaching from the southwest will bring showers to Southwestern CT later Saturday afternoon while the rest of New England waits until after dark for showers to move in. Expect rain, heavy at times, for a good part of Sunday with cool conditions, then gradually warming temperatures but lingering showers amidst Southern New England breaks of sunshine on Monday. By Tuesday, the weather pattern becomes a bit faster-moving, and this will bring another chance of showers with the next weather system. -Matt
With the atmospheric pattern finally beginning to move again, New England weather regains its changeable nature as we head into the weekend. Of course, with the strong jet stream winds aloft lifting into Canada, these winds that steer our storm systems won't be available to keep storms moving quickly, so instead we'll end up turning our attention to a slow-moving energy center moving east out of the Great Lakes this weekend, interacting with significant Pacific and Gulf of Mexico moisture for an intense rainstorm in the Ohio Valley, the Mid-Atlantic, and eventually into the Northeast.
In the meantime, new air has moved into New England and we'll all feel it on Friday, and through the weekend. This new air is Canadian in origin, which means it's cool and dry. The clockwise flow of air around the center of high pressure - the center of this dome of Canadian air - will mean a northeast and east wind will continue to blow through New England, and in addition to the cool and dry air moving in, these winds will be blowing across cold ocean waters that are only just barely above 40 degrees! The result will be a very brisk day along all east and northeast facing coastlines, where we'll struggle to get out of the upper 40s, while interior locales, farther away from the ocean influence, will rebound into the 50s, while Western New England from Hartford, CT, to the Champlain Valley of Vermont, should rise into the 60s. Still, this is some 15-20 degrees cooler for most communities than yesterday, so it's important that we not be fooled into expecting another day of summertime warmth by the sunny appearance! One weather factor that does remain constant, unfortunately, is very dry air, especially away from ocean influences which especially includes most of New Hampshire and interior Maine. Through most of New England, elevated fire danger continues Friday and into Saturday, as well. After multiple brush fires over the past several days, let's all remember that one of the most common causes of Northeastern US brush and wild fires are poorly extinguished smoking materials, followed by poorly managed burning, which fire officials say was responsible for a fire that burned up to 100 automobiles at a junkyard in Middleborough, MA, on Thursday.
As mentioned above, weekend attention will turn to a storm that made headlines at the beginning of the week as it brought blizzard conditions to the Northern Plains. Though it's packed full of energy, this storm has been cut off from the fast jet stream winds aloft that normally steer storms and keep them moving, as the jet stream winds aloft have retreated quickly into Canada, leaving this storm behind to drift only slowly east, tapping moisture from the Gulf of Mexico and arriving into New England Saturday evening/night into Sunday.
This sluggish storm will be dragging increasingly warm and humid air northward ahead of it in the counter-clockwise flow of air around the center of low pressure. After a cool start of filtered sunshine through high altitude clouds Saturday morning, the clash of incoming warmth and moisture with the cool and dry air already in place over New England will mean increasing clouds through the day Saturday with heavy rains from Pennsylvania to New Jersey, and only a slow progression of this rain shield into New England as it battles our cool and dry Canadian dome. A few showers are likely to arrive in Southwestern CT and extreme Western MA Saturday afternoon, though for most of New England the rains will hold off until after sunset Saturday night, making Saturday by far the pick of the weekend days.
A big reason we can't bank on a decent day Sunday is because we have to remember that a storm slow to move in also is likely to be a storm slow to move out, and with so much energy heading directly for New England, and the clash of two airmasses occurring directly overhead, there are a few likely results. The first likely result is for bands of rain to fall heavily at times as long as the storm is nearby - which would stretch from Saturday night through Monday! This doesn't mean it's going to rain the entire time...but it does mean various parts of New England will have to deal with rain showers and downpours coming and going through that period. The heaviest rain is likely to move through Connecticut the latter half of Saturday night into Sunday Morning, and through the remainder of New England during the day Sunday into Sunday night. Though rainfall amounts are likely to be much heavier in Southern New England than in Northern New England - ranging from one to two inches south (with some higher amounts, especially in CT) to an inch in Central New England, to about a quarter inch along the Canadian border, with rain barely reaching Northern Maine by Sunday night. The other likely result of a storm moving along such a dramatic clash of airmasses is for a large difference in temperatures between the north side of the storm and the south side. If this area of low pressure moves directly across New England, parts of extreme Southern New England would be able to warm into the 60s on Sunday with breaks of sun between the downpours. It still appears, however, that the storm center will pass just south of New England, keeping just about everyone on the cool side of the storm with temperatures in the 40s, and enough mild air squeaking onto the South Coast to boost temperatures into the 50s there. By Monday, another wave of low pressure will move across New England...though this time perhaps the track would be over Southern New England, which would keep cool periods of rain in the north, but allow those aforementioned breaks of sun and somewhat milder temperatures to move into Southern New England amidst some showers.
Though I can't rule out another round of showers with a quick moving storm center as our atmospheric pattern finally starts to move a bit quicker on Tuesday, I think the trend for the midweek should be a for a dry and somewhat cool shot of air that will gradually modify (warm) near or above normal by the week's end. In the longer term, the supply of cool air will run out and it looks like a more prolonged warming trend will be ready to move into New England for the first week of May.
Have a fantastic weekend!
Matt
Matt's Technical Meteorological Discussion: Updated Friday, April 21 at 12:15 PM
Not many changes for the upcoming weekend scenario so for the most part will refer you to yesterday's technical discussion in the next few days but I do have a few additional thoughts before we dive into the longer range. First, the timing looks to be close to yesterday's thoughts, though it's looking more and more like a wet afternoon for all of the SW half of CT and now also for Western MA and Southern VT as strong warm and moist advection takes hold from 18Z onward with a well defined speed and directional convergence zone ahead of the corridor of approaching 850 llvl jet cranking at 50-60 kts over SE NY later Sat. This llvl jet axis will shift east, enhanced by the squeeze between lingering ridging over the Canadian Maritimes and the Western Atlantic, and the incoming trof from the Great Lakes. Surface low still progged to pass S of NewEng and if one looks only at the synoptic setup with a 1022 high over Eastern Canada and a surface wave cranking south of NewEng, this is favorable for a strong east if not even a northeast surface wind later Sat Night and surface Theta-e progs confirm some cool advection across the Gulf of ME into Southern NewEng. This sets up a differential advection favorable for heavy precip event, and with tropical airmass feeding into the equation, 12Z NAM responds accordingly by cranking out several inches of precip, esp in Western NewEng. Canadian Ensembles are on-board with this and I expect the 12Z GFS to be onboard with at least what will end up being a 2"+ rainfall western half of NewEng - centered on CT/Wrn MA - and a 1"-2" rainfall farther E, with amounts dimishing northeast with nothing in Northern ME, closest to surface anticyclone. Heaviest pd of rain is Sat Ngt extreme Western areas but Sun for the remainder of NewEng. Lo and behold, Monday coastal system now showing up on the NAM which is close to Canadian guidance. Regular readers know this was the original thinking on the system but have been compromising temps given insistence of GFS and ECMWF on getting northern edge of warm sector into Srn NewEng. Still early to bite too hard but a well-established easterly flow will not promote any warming, nor will the heavy banded precip that would result on the north side of the upper low and its surface reflection. From the beginning of the week the Ensemble members were indicating this low has the potential to become a powerful creature and we will need to continue watching it, especially given that its source region is over the Mid-Atl, where it will be tapped into Gulf of Mex moisture. Second shot of heavy QPF still looks like a good bet with this wave, though track will determine where it is. Not impossible for thunder southeastern NewEng later Mon and heavy rain north if this low tracks directly over Ern MA. Bottom line is we're looking at inches of rain to fall this weekend through Monday across most of NewEng. Ground is dry and needs this rainfall, but may fall heavily enough for flash flooding latter half of Sat Ngt in Western MA and Western CT and this potential will need to be monitored this weekend.
In the longer range, there are sure signs of spring for the beginning of May, and also signs that after another wave on a front passes thru with showers on Tue, a dry flow will take hold, though perhaps not exceptionally warm. Canada is one conflicted country, speaking strictly of weather this week. Our cool air is spilling out of Eastern Canada while currently strong positive height anomalies over and west of Hudson Bay are producing 850 temp anomalies of +12 to +16C!! This is tremendous warmth but at this point it remains locked our west as troffing continues. Even after Tuesday's wave, it appears a strong surface anticyclone settles south out of Central Canada, bringing a shot of Canadian chill to the tune of 4 C below normal at 850 mb, tho I don't think we'll verify that cold as downsloping flow and boundary layer airmass modification are likely to battle back. The end result may be a stretch of a few days that are pleasant days of near normal temperatures with enough dry air to lock in quiet weather thru the end of next week.
It also appears as though this surge of cool air is the last gasp of Canadian chill for now, and what this means is that we're left with a weak trough but little low level cold to pour into it. This transition occurs as energy from a storm plowing into the west coast at the middle of next week traverses the lower 48 and passes off the East Coast south of NewEng by next weekend, bringing with it intense severe weather outbreaks from the Lower MS River Valley to the Southeastern and Mid-Atlantic US next Saturday and Sunday while providing perhaps a bit of moisture input aloft for northern stream shortwaves that will be sliding thru NewEng - the best defined perhaps on Sat with Northern NewEng showers and possible thunder. Thereafter, thickness diffluence spreads from the MS Valley to the northeast and Mid-Atlantic which favors a week with multiple threats for showers and thunderstorms, and with the diffluent flow aloft and slow moving energy over the SE US, along with a slowly westward retrograding trough axis to a position west of NewEng, we will have to be on-guard for heavy rain events, though outside of these events temps should run above normal with little cold air available in Canada.
Have a great weekend and stay dry!
Matt
