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:
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We continue our jump into summer across New England as we cruise into the weekend, en route to an appropriately summer-like Memorial Day weekend to unofficially kick off our New England summer season! The jet stream pattern - the fast river of air aloft in the atmosphere that steers our storm systems and acts as a thermostat for the atmosphere, separating cold to the north from warm air to the south - continues to shift from a pattern that featured a cool trough (dip) over the Northeast, to a warmer ridge (bump). This will put New England squarely on the warm side of the thermostat for the holiday weekend.
The transition to a summer airmass is already underway across New England, as was evidenced by light early morning rain showers associated with a surge of warmth and moisture aloft, and evidenced by stubborn low altitude clouds and fog along the South Coast for the first several hours of Friday. Elsewhere, the sun was able to warm the atmosphere quickly enough to avoid widespread cloud cover early Friday, though an increase in available moisture through the lower levels will allow for more clouds to bubble up region-wide Friday afternoon. Still, sunshine this time of the year is effective (remember that we're less than a month from the summer solstice - the strongest sun angle of the year) and what we see of it will boost temperatures into the 80s for Northern, Central and interior Southern New England! Within several miles of south-facing coastlines, however, temperatures will be held cooler due to the additional cloud cover and the cooling effect of the ocean waters.
Farther west, the disturbance we've been watching all week since it came ashore over Southern California on Monday continues to slowly track eastward across the Great Lakes and into New York State. This system has a long history of producing severe weather, and continued to produce a widespread severe thunderstorm outbreak requiring several tornado watches in the Ohio Valley on Thursday. The focus today will be primarily through Upstate NY southward to the Mid-Atlantic, though by mid to late afternoon Friday, showers and thunderstorms will spread into Western New England and given how warm it will be, and the increasing moisture through the atmosphere, thunderstorms will have the potential to grow strong, dropping locally torrential rainfall and frequent cloud to ground lightning. Localized bursts of damaging winds are also possible in some of the heavier thunderstorms in especially Western New England.
While the showers and storms will have spread into Western New England by late afternoon, Eastern areas are likely to stay mainly dry until Friday evening, when scattered thunderstorms advance eastward and periods of rain and thunder will fall for most of New England Friday night, with the heaviest amounts nearing an inch across parts of Northern New England, and perhaps a secondary maximum near the South Coast due to two separate and opposing frontal boundaries - one is the cold front we've been watching this week, settling south into New England from Canada, and the other is a surge of warmth and moisture from the south, responsible for the south coastal fog and low clouds earlier on Friday.
With the energetic disturbance moving across New England not likely to pass through completely until during the day on Saturday, lingering clouds that break for sunshine Saturday morning are likely to yield to new scattered showers and thunderstorms along the lingering surface cold front, which will be draped over Southern New England Saturday. These showers and storms would be most likely from 11 AM onward - and most widespread during the afternoon - occurring from Hartford, CT, to Portsmouth, NH, points southeast. Where the most showers roll through, temperatures will be held in the middle 70s while other areas rebound closer to 80. Given a light wind flow, coastal locales may actually be able to warm into the 70s, as well, before feeble sea breeze circulations establish later in the day.
The summer warmth that's been building from the Southwestern U.S. through the nation's midsection and even northward into Central Canada will be on the move and destined to move into New England as the holiday weekend wears on. By Sunday, this warm and increasingly dry air will yield a gorgeous blend of sun and clouds, and with the surface wind direction pointing out of the northeast and east - off the ocean - coastal communities will remain pleasantly cooler while interior locales climb to either side of 80 degrees, where a lesser but still evident ocean influence will be present.
By Memorial Day Monday, all signs point to a strengthening southwest wind, which is a warm wind direction for almost all of New England, except, of course, south-facing shorelines. With enough dry air in place for nearly full sunshine, the combination of sunshine and warm air should have no problem boosting temperatures well into the 80s - even at the coastline - with some spots hitting and exceeding 90! This deep summer warmth will last through midweek, and even after the passage of a cold front that's likely to bring a round of strong thunderstorms by Thursday, a warmer-than-normal pattern is likely to continue through the first half of June!
Matt
Matt's Technical Meteorological Discussion: Updated Friday, May 26 at 1:30 PM
I suppose to forecast strictly by the models we'd have to ammend the forecast for a dry evening in the Boston metrowest area as 12Z NAM has stripe of 0 precip along and just north of the Massachusetts Turnpike. Tough to believe given bands of convection - some severe - propogating northeast toward NewEng and I will leave the going forecast alone for convection to advance northeast. I expect an onshore flow so stable that fog and low clouds linger at the immediate South Coast to inhibit surface-based convective potential in most of CT/RI but interesting to note the CAPE gradient that sets up from NW CT to Central MA and BOS area this afternoon and eve. Oftentimes I've seen strong thunderstorms develop on CAPE gradients like these, so would think from this gradient north and west into the increasingly unstable heated airmass we'll be looking at plenty of convection with localized damaging gusts remaining possible and most widespread threat being torrential downpours and frequent cloud to ground lightning.
Though intensity of convection should diminish after dark, periods of showers, downpours and thunder continue thru the overnight with max QPF being found along southward sagging cold front of the North Country and with continued warm/moist advection and assoc upglide in far Southern NewEng. Perhaps a few lingering showers early Sat but I think a break in the action.
As for later Sat, frontal boundary still lingers over Southern NewEng and with moist and unstable airmass in place and vort max moving overhead, expect convection to re-energize Sat late AM into the afternoon esp from HFD to PSM points SE while drying moves in farther N and W. That drying trend continues behind shortwave late Sat and Sat ngt with Sun, Mon and Tue all looking plenty dry mid and upper levels. Sun still looks like an onshore flow which means coolest coast, of course, tho warm enuf airmass that while ocean will be mitigating effect farther inland, it won't seem like it to the general public as highs settle either side of 80. The difference will become more evident when we swing to a land breeze and maximize the potential of our warm airmass Memorial Day and Tue. One of these days very well may hold a NewEng avg high temp over 90, but that would require limited mid and upper level clouds along with a downsloping flow (even a weak one). I think we can get downsloping but we also may have some degree of midlevel clouds with a northwest flow aloft - at least in the Northeastern half of NewEng. This really is a moot point, however, as many areas will surpass 90 on both Mon and Tue regardless.
Continued warm string lasts into cold frontal passage on Thu which will have tropical tap and is likely to bring intense convection and heavy rainfall amounts tho perhaps heaviest to our West Thu with our fropa holding off until Fri. This will be next week's fun.
Enjoy the holiday. I'm back on Tuesday.
Matt
