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:
Tuesday morning dawned significantly warmer than its predecessor - a false sense of how the day would transpire for those who don't keep up with the weather! After reaching 80 degrees in the City of Boston on Monday, 81 in Concord, NH, and 82 at Windsor Locks, CT, there was plenty of heat left near the ground and an active wind to keep the atmosphere from cooling quickly. Nonetheless, a cold front settling southward out of Canada overnight Monday night did its job of shifting winds to blow from the northeast, ensuring new air would take hold of New England.
In fact, the relatively mild start Tuesday morning won't mean much given ocean temperatures in the upper 50s and an onshore wind flow. Though plenty of dry air is still present, moisture has begun streaming northeast well ahead of the primary area of energy and moisture poised to crank up an intense storm over the Upper Midwest and Upper Great Lakes. The result has been high altitude clouds riding across the North Country, and the clash between airmasses aloft has been creating stubborn and complex pockets of middle altitude clouds that are visible through the satellite links at left (during the day, the visible satellite imagery is especially helpful) and have been resulting in overcast skies at times in Central, Western and Northern New England. This clash of airmasses several thousand feet above our heads is simply the precursor to a complex series of events that will mark a significant shift in the weather pattern, destined to bring cooler air into the Northeast for the upcoming weekend.
Nonetheless, amidst sun and clouds we should stay mostly dry - a sprinkle is an outside possibility in Western New England - with the combination of cool Canadian air and our cool onshore breeze keeping temps down for all but the State of Connecticut, where we remain far enough away from the eastern coastline and far enough south from the center of the new cool airmass that we should still warm into the 70s.
Meanwhile, a large storm will be winding up across the Central Plains today, moving northeast along a strong cold front and strengthening as it heads toward the Great Lakes on Wednesday. The cold front this storm will travel and grow along will be trailing from a separate strong storm, slowly moving east across South-Central Canada. The counter-clockwise flow of air around that particular storm will have already dislodged a significant chunk of cold air from Central Canada, waiting and available across the Central part of that nation. With the rapid strengthening of the new storm system, and its associated counter-clockwise flow, this cold air will be tapped and thrust southward toward the developing low pressure center, invading the Upper Great Lakes at the same time that tropical moisture wraps around the new storm center, creating bands of accumulating snow and record cold in the Upper Midwest and Upper Great Lakes. Ahead of this storm, however, warm and moist air will come streaming northward, tapped first from the Pacific Ocean and next from the Gulf of Mexico. The result will be a surge of warmth and moisture that begins aloft on Wednesday, and a bit later in the lower levels of the atmosphere.
After a partly cloudy Tuesday night, Wednesday's first surge of warmth and moisture will come several thousand feet in elevation. Nonetheless, the clash with our cool and dry airmass in place already will mean plenty of clouds blotting out morning sunshine, and these clouds will drop a few showers from time to time from mid-afternoon onward. The increase in cloud cover, along with a developing onshore flow, will help to ensure temperatures stay quite cool for New England's midweek. By Thursday, the strengthening storm wrapping up through the Eastern Great Lakes will continue to increase onshore flow here at ground level, at the same time the counter-clockwise flow around this storm helps to turn winds out of the south up the Eastern Seaboard. This adds an interesting additional complexity to the forecast, as an area of showers and thunderstorms has been evident in a well-developed circulation off the Carolina coastline for the past several days. This is the same low pressure system I discussed here last week, and is still spinning off the Southeastern United States coastline. As winds increase from south to north aloft, this circulation will nudge northward, and its moisture may help to infuse an already intense surge of tropical warmth and moisture. The end result will be a band of rain and embedded thunder on Thursday, followed by a sharp wind shift that will mark a strong cold front - the leading edge to the deep Canadian cold responsible for Midweek Great Lakes snow. This air will be cold enough to fire streamers of lake-effect snow off of both lakes Erie and Ontario by Friday night, with gusty west winds continuing to carry cold air into New England, but here in New England we will also see drier air moving in at the same time. The result will be a very limited threat for any snow showers in most areas, though there will be a few exceptions. In most areas, the incoming dry air will allow for breaks of sunshine amidst lingering clouds on Friday, warming temperatures enough for leftover light scattered showers to fall as raindrops on Friday, though in the mountains enough cold air may be present for a mix of rain and snow showers. Along the spine of the Green Mountains, moisture input from the lake-effect precipitation bands off of Lake Ontario will likely create snow showers Friday night into Saturday!
Elsewhere, Saturday may actually end up equally cold or even a bit chillier than Friday with regard to numbers on the thermometer - especially when taking the minimum temperature into account for daily average temps - but with lighter winds and a bit more sunshine, it will likely be a more comfortable day overall.
Technical Discussion: Very busy schedule today...see you tomorrow.
Matt
Matt's Technical Meteorological Discussion: Updated Monday, October 9 at 1:35 PM
Nary a cloud in the sky today with deep dry air and split energy on the Eastern Seaboard as upper low stays south and westerlies ride north. WSW flow has advected both warmer and more moist airmass into NewEng and this will be reflected in overnight temps esp prior to cold fropa tho that fropa takes place by around midnight most areas...a bit later far Srn NewEng. This leaves a NE wind for most areas on Tue which will bring a dramatic airmass difference.
Strong cyclogenesis is set to take place Tue into Wed as potent Nrn and Srn stream shortwaves merge for deep upper low over Great Lakes. I think it's a bit early to try and get too specific and too fancy here in NewEng but a lot can be garnered from a synoptic thought process. First, the large storm surface and aloft S of Hudson Bay at the start of this week is yanking down a chunk of Canadian cool that will sit in waiting just over the border, north of the Grt Lakes, waiting to be tapped. Meanwhile, it will drag a cold front across the Plains and Srn stream wave will induce cyclogenesis along the frontal boundary. A combo of PG flow and ageostrophic flow will tug this well of cold air south, which will in turn greatly increase baroclinicity as it plows into well-established tropical feed from Pacific and Gulf. The result will be the intense cyclogenesis progged for several days now as the surface low pulls into the Great Lakes. Last week I discussed the likelihood of record cold through the Plains and early season snow in the Upper Midwest and that still appears to be the case even thru the Upper Great Lakes, with the potent cold penetrating far south into the TN valley where record cold is likely on Fri.
Of course, NewEng is ahead of the system which in this case doesn't start out quite as exciting but proves to be equally if not more challenging for a longer duration. That is, our first chore is determining when to bring precip in and to what intensity. The bottom line here is that if we maintain a SE sfc flow on Wed, which we should do with a nose of sfc ridging holding on over NewEng, the warm front gets squashed by NYC and we can forget about any warming. In fact, have gone rather significantly below statistical guidance for Wed given warm advection aloft but combo of sfc ridging and onshore flow holding cool dome at the sfc and this will create plenty of clouds along with sct showers in isentropic lift over shallow dome. Well ahead of the cyclonic vorticity advection and deep tropical warmth or moisture, it is unlikely we'll see any heavy precip, but the clouds and scattered showers we do see will hold temps down significantly, esp when coupled with the onshore component of the wind. Early Thu is when our greatest warm and moist advection arrives, and therefore should be when our heaviest precip arrives. Tho the guidance will continue to put out timing diffs, synoptic thought must prevail and that highlights late Wed Ngt thru the first half of Thu. There is likely to be a break after this initial slug of WAA precip, though expanding wind field from intense low pressure well to our west will develop, esp thanks to PGF between departing high and incoming low. Fropa timing looks to be Thu Ngt when intense winds are possible across the Northeast ahead of front with strong llvl and midlvl jet overhead - this certainly has the potential to be a damaging event for higher terrain. Fri has the potential for damage as well, tho what may save us is that there is no well-developed high building in, and the tightest gradient is found under the belly of the primary low, still over the Upper Great Lakes. Thus, while cold air spills in and the winds howl a plenty, we may avoid damage on Fri, tho there is a core of intense wind rotating around the belly of the primary low that meteorologists should continue to pay heed to. There is enuf cold air moving in on Fri that I have no problem putting Green Mountain snow showers in the forecast. The remainder of the mountains will probably see a brief period of flurries or snow showers as moisture departs late Thu Ngt or early Fri, then there will be lingering instability showers on Fri esp in Nrn NewEng when most of the mountains are likely to see at least rain/snow mix showers in convective clusters tho insolation between cumulus will mean not totally a winter scene. By Fri Night, however, lake effect streamer should be cranking off Lake Ontario and given instability and moderately fast wind flow this will carry into the Greens where upslope flow will enhance them and large area of snow showers should result, getting skiers awfully excited. This setup should continue thru Sat.
Enjoy your day!
Matt
