A quick-hitting but intensifying storm system will bring early winter-like conditions to parts of the Northeast for the second time in less than a week. The snowfall will be plowable for many inland locations in New York and New England. Holiday and commuter travel may grind to a halt in some places, as the snow is expected to intensify during rush hour in parts of New England.
The weak wave of low pressure was already producing rain and show showers in West Virginia, Pennsylvania, and New York’s Southern Tier as of Monday evening. The surface low was riding along a cold front downstream its parent upper-level low while an area of weak high pressure was funneling arctic air from Canada southward toward the Northeast. The transport of warm air from the south over the cold air from the north has helping to produce light precipitation for most of today. The snow will gradually increase in both coverage and intensity as it treks toward the Atlantic coast. Unfortunately, the snow will reach peak intensity just before the morning rush hour across much of New York and New England, making for a treacherous commute.
Precipitation is expected to remain light until the low reaches Southern New England late overnight Monday into Tuesday. Here, the low will become intertwined with the warm conveyor belt flowing in from the Atlantic Ocean. The contrast between the relatively warm Atlantic and the cold Arctic airmass will deepen the low pressure system as transport of Atlantic warmth and moisture intensifies. The convergence of these two airmasses will be responsible for the intensifying snowfall rates Tuesday morning in eastern New York and New England. Snow may consequentially accumulate at rates upwards of 1″ per hour from the Taconics of New York to the coastal waters of Maine.
Naturally, the forecast is complicated by the highly sensitive boundary separating rain from snow. The boundary will establish itself near the convergence of the Arctic and Atlantic airmasses as it guides the low pressure system to the northeast. Model guidance suggests that the boundary will likely slice through the Hudson Valley and roughly follow the Massachusetts/Connecticut border before cutting northeast across Massachusetts to Massachusetts Bay. Major cities like Springfield and Boston will find themselves caught in the dicey corridor within the vicinity of the pesky boundary where the precipitation may fall as both rain and snow.
Northern Pennsylvania and southern and central New York from Elmira along the I-88 corridor to Albany should expect 2-4″ of snow through the overnight hours. Heavier snowfall of 4-8″ will fall in the Catskills and Taconics, where elevation and greater moisture availability will aid snowfall rates. Hudson Valley cities like Poughkeepsie and Kingston will straddle the aforementioned rain/snow boundary so rain at the onset late Monday evening will confine totals here to the C-2″ range. The snow will clear Pennsylvania overnight, but the Mohawk Valley, Capital District, and upper Hudson Valley will have to confront the snow through the morning rush.
The snow will pose a more significant threat to New England given the timing of its peak impacts. Heavy snow will develop in western Massachusetts and southern Vermont northeastward to coastal Maine early Tuesday morning. The initial thump of snow could snarl traffic long the I-90 corridor from Albany to Worcester, where heavy snow will begin to accumulate just before sunrise when blacktops will be coldest and lightly traveled. Low elevations like the Connecticut Valley will likely receive 2-5″ of snow while higher elevations like the Berkshires and the hills north of Worcester will pick up 4-8″ of the white powder. North of Massachusetts, snow may accumulate 6-10″, with cities like Nashua at lower elevations receiving 3-6″. Snow will come to an end by late afternoon in southern New England, and during the evening in northern New England.
Snowfall ratios will decrease toward the Connecticut border where rain and sleet will mix with the snow, keeping totals in the 1-2″ range. Precipitation will be entirely rain in most of Connecticut, Rhode Island, and southeastern Massachusetts. Precipitation will begin as rain in Boston but the rain will mix with and changeover to sleet and snow between late morning and early afternoon.
Behind the snow, an arctic invasion will make for the coldest Thanksgiving in decades, if not since records began for some cities in the Northeast. At least it will be dry. The next system is expected to bring precipitation Saturday night through Sunday.