The advertised active storm pattern will continue this week, with major contributing players being Pacific energy and moisture, Gulf of Mexico moisture, and arctic cold. The result will be prolonged wintry precipitation that will wring out snow, sleet, freezing rain and rain for New Englanders Tuesday late afternoon through Wednesday. Though quieter and milder times are ahead for Valentine's Day and Friday, another storm appears in the works by the end of the weekend.
For now, high pressure building across the Great Lakes and Ontario has coupled with a strong storm east of Maine to send a northwest wind sailing across New England on Monday, bringing gusts to 45 mph and enough cold air for wind chills to hover in the single digits for most spots at the warmest time of the day. Though sunshine has been the prevailing weather condition for most, clouds have been a steady presence in Maine, where the odd phenomenon of warm air coming from the north has been evidenced today, with warmth wrapping around the back of the strong storm east of the Pine Tree State. Farther south and west, most clouds that develop today are puffy, fair weather cumulus clouds that may grow tall enough for a few mountain snow showers. By Monday evening, winds will remain active and wind chill values will dip back below zero, with overnight temperatures plunging into the single digits for most - somewhat milder in Southern New England urban centers and colder in Northern New England locales - as winds begin to quiet after midnight and mostly clear skies prevail with the exception of Maine.
A quiet start Tuesday morning will disguise the wintry mess that's en route by Tuesday evening and night. For quite some time, those of you who read regularly have seen me playing up this continued pattern favorable for wintry weather, and the same tell-tale signatures remain. From the Northern Pacific, a fast polar jet carries substantial chunks of energy inland to the Pacific Northwest and Vancouver, the product of a semi-permanent Aleutian low pressure cell over the Islands of Alaska that launches these strong and cold energetic disturbances east. From the Gulf of Mexico, deep moisture is evident on satellite imagery, streaming north into Eastern Texas, and this moisture will couple with the energetic Pacific disturbances that are diving southeast across the Rocky Mountains. Together, the energy and moisture will merge over the Southern Plains and Mississippi River Valley, creating a series of moisture-laden low pressure centers that will ride northeast in a developing deep southwesterly wind flow aloft, ahead of a developing Central U.S. "trough," or dip, in the jet stream winds that steer our storms. As the first moist wave rides northward across the Upper Tennessee Valley and the Eastern Ohio Valley, it will encounter the dense cold air across the Northeast, which will be unwilling to yield easily. The result will be a battle between the warm and moist air associated with this storm, riding northward, and the cold, dense air over New England that will serve to force the storm center east. Thickening clouds Tuesday will still come with a day that feels milder than its predecessor as temperatures rise only a few degrees higher but winds will be much lighter - and eventually those clouds will yield to snow developing from southwest to northeast Tuesday afternoon and evening between 3 PM and 7 PM, encompassing most of Central, Southern and Western New England over the course of that time. During the first part of Tuesday night, snow will continue to fill in across Northern New England and fall heavily at times for many spots, even in Southern New England.
With a strengthening southeast wind blowing across the Atlantic waters, the South Coast will see a change to rain, while interior locales of Southern New England will find late Tuesday night changeover to sleet and freezing rain, with snow continuing to change to sleet between midnight and dawn for the Route 2 corridor of Northern MA all the way north to Central Vermont and New Hampshire. Farther north, the mountains will see more snow, though during the day on Wednesday it seems likely that even the North Country will find sleet mixing in, leaving accumulations of 6"-12" in the North Country, with much less snow but a burst of heavy and plowable snow still likely Tuesday night when the storm gets under way as far south as interior Southern New England. With multiple waves of low pressure rippling north along a complex frontal system and taking incrementally farther east tracks, expect Wednesday's follow-up storm center to once again be packed with moisture, but lacking in cold air. Part of the reason for the lack of cold air is the steady eastward retreat of the cool high pressure cell that initially supplied it, moving east over the Canadian Maritimes. This leaves a deep southeasterly flow ahead of each wave of low pressure that erodes the cold enough to bring a mostly rain and perhaps North Country freezing rain scenario if enough surface cold air remains trapped in the lowest couple of thousand feet later Wednesday into Wednesday evening, which remains to be seen.
Valentine's Day Thursday leaves an "occluded" airmass - that is, an air that may have initially been cool behind the storm but mixed with ample warm air to allow temperatures to rise above freezing on average across New England with lingering clouds for at least the first part of the day but the likely emergence of sunshine by the end of the day. Another strong upper level disturbance will prompt surface storm development over the Great Lakes Thursday into Friday, pulling into Southeast Canada and yanking a small tug of warmer air up ahead of it on a strengthening southwest wind that will boost temperatures into the lower 40s for some, while likely ushering in a swath of clouds with perhaps a few rain or snow showers late in the day - mostly rain showers where temperatures rise above 40, of course. Behind the front will come cooler and drier air for the weekend, though with the cold front stalling to our south and east, this will set the stage for a potential late week northeaster as the active flow of Pacific energy continues to tap Gulf Moisture!
Have a great Monday.
Matt
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