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:
After a record-breaking warmth of 74 degrees in Bridgeport, Connecticut, on Tuesday, Wednesday winds have ushered cooler air back into New England. Though temperature variation will be a part of the forecast in the coming days, the one near-constant between now and the weekend will be sunshine, and lots of it, with dry air firmly in place.
Temperatures actually fell for a time Wednesday morning as winds kicked up from the northwest, increasing pre-dawn in Northern New England, and over the course of the morning farther south. This increase in wind comes as a sprawling area of high pressure - fair weather - located over Hudson Bay, Canada begins to move east. This expansive fair weather center, like all high pressure cells in the Northern Hemisphere, has air flowing clockwise around its center, and this means a northerly and northwesterly wind across New England in advance of it. Further increasing wind speed is the squeeze between this high pressure center, and a strong low pressure center (storm) located in extreme Eastern Canada - a difference in atmospheric pressure means a consistent motion of air, and this setup will contribute to gusts of up to 40 mph Wednesday afternoon. These winds, blowing out of Eastern Canada, are responsible for carrying cooler and drier air southward. The cool nature of the air brought the early morning drop in temperature, while the dry nature of the air has two effects: evaporating clouds that were in Southern New England early, and drying the landscape to allow dead vegetation from last growing season to become dry and brittle. Combined with active winds and good exchange of air from the ground to a few thousand feet in the sky, this dry ground cover can serve as good fuel for fires, and fire danger is high on Wednesday afternoon for non-snowcovered locales of Southern New England. Of course, the other obvious effect of dry air is to allow for plenty of sunshine, and that sun will battle back against the arrival of cool air to keep temperatures near normal for daily highs.
A dry airmass warms quickly with the help of sunshine, but also cools quickly when sunshine is removed. So, after sunset expect temperatures to drop fairly quickly Wednesday Night, falling into the teens and 20s north, and 20s to lower 30s south, and with a continued wind at 10-20 mph, wind chill values will run squarely in the teens north and 20s south - a true winter chill! This cool start will yield a cool day on Thursday, with temperatures holding just under 50 for many areas - barely above in Southern New England. The atmospheric squeeze play will still be on, meaning winds will remain active and will gust even stronger than Wednesday, reaching 40-45 mph in some areas!
As the sprawling and strong high pressure cell in Central Canada migrates east later in the week, New England will remain under the influence of dry air, so that even as temperatures moderate briefly on Friday, sunshine remains amidst just a few clouds associated with the passage of a weak cool front Friday afternoon and evening. Behind this front, a reinforcing shot of cool air will fall into place for Saturday, while a significant slug of warmth and moisture builds over the Ohio Valley, and a series of energetic disturbances continue to ride from the Pacific to the Great Lakes, resutling in the potential for Midwestern flooding and severe weather, but deflected from moving into the Northeast until dry and cool Canadian air can relinquish its control. By Sunday, the dry air will break down gradually, but steadilly, resulting in thickening clouds and the likelihood for showers to develop later in the day. Rain will move across New England Sunday night into early Monday with one low pressure center passing to our north, and another to our south. Though mild air may follow this disturbance for 24-48 hours, a shot of cool air will move into New England by midweek next week.
Technical Discussion: None today.
Matt
Matt's Technical Meteorological Discussion: Updated Monday, March 26 at 1:15 PM
Clouds and precip come courtesy of isentropic lift coupled with leading vort max ahead of primary vort moving across Great Lakes. First vort max brought multiple CG lightning strikes even tho light rain for a time, then the boundary layer moistened. We're in a similar situation tho without the lightning for Nrn NewEng as I write, which makes sense given decreased llvl speed convergence and decreasing theta-e gradient. Still, as air becomes more saturated, elevated instability increases and Wrn NewEng may see thunder before the day is out. Farther south, slug of warm and moist advection has been less focused thus far but still will be sufficient to generate sct shra and then dynamic lift assoc with and ahead of main vort max this eve and tonight will be enuf to generate widespread shra, downpours and isolated tsra perhaps from Wrn MA to CT. Wind shift early Tue truly is a trof rather than a cold front at its leading edge, tho I suppose technically it's still a cold front, just with the temp gradient lagging far behind. The airmass change is lax in coming south because it must wait for the eastward movement of the high over Hudson Bay, which happens but not until later. This actually means the passage of the wind shift favors more warming than otherwise in Srn NewEng as winds turn from the northwest and downsloping kicks in, warming many locales of Srn NewEng into the 70s as this downsloping helps to break up deck enuf for sun. I know RH progs are very high, but that's similar to what we're seeing upstream in OH Valley today and tho clouds are numerous, sunshine is effective and temps have been soaring. We're likely to see the same result in Srn NewEng on Tue afternoon after morning fog and low clouds that will be stubborn, with deck hanging until late morning when wind shift kicks in a bit. Still, we're looking at a wind shift line/front that doesn't completely clear Srn NewEng, and a few extremely weak mesoscale waves of low pressure will develop along it. This slight lowering of pressure, along with the warming interior, is likely to favor a sea breeze for almost all Southern NewEng coastal locales, whereas BOS may not get over 56 or so degrees before the sea breeze initiates, while LWM hits 70. A bit trickier on the SCoast of CT where GON may go to 62 or so and then fall back, but stronger NW gradient flow in HVN argues for mid 70s! Weak vort max Tue afternoon/eve may spark a thunderstorm in CT with sfc based LIs approaching 0.
Wed thru Fri brings installment of fresh, clean, dry and cool Canadian air. High amplitude pattern flow suggests quick warming on Sat, and perhaps several degrees above normal, before rain event to end the weekend and cooler air to begin April.
Matt
