A definite change in the weather pattern is unfolding for New England, removing us from our multi-week lull that’s delivered winter complacency for some. The awakening of winter comes as the feed of Pacific energy and moisture comes alive in response to the recent splintering of the Polar Vortex in high latitudes.
The Polar Vortex is a semi-permanent storm that represents a swirling mass of cold air and atmospheric energy that resides near the North Pole. Once a consolidated mass that would send occasional surges of cold and energy southward, modern winters in a warming planet have redesigned the behavior of the Polar Vortex.
A recurring feature of modern winters in response to a warming planet, the split of the Polar Vortex represents the break-down of consolidated arctic cold in response to warmer air near the arctic. Particularly high in the sky, this splitting causes a splintering of the cold and energy, sending intense cold to various high latitude locations in the Northern Hemisphere.
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This winter, at least thus far, New England has avoided deep arctic plunges, with the fractured shots of cold affecting Siberia and Europe. Atmospheric energy, however, is a bit more fluid and nondescript, carried by the jet stream winds aloft and transported far and wide across the Northern half of our planet.
Last week we saw plenty of these energetic disturbances, but their path was dipping across Canada, moisture-starved as they reached New England. A subtle but important shift southward in the jet stream this week has big implications for this parade of disturbances.
Suddenly, they come into the Lower 48 from across the Pacific, carrying moisture with them and opening the Gulf of Mexico and Atlantic Ocean for additional moisture input. The result is the chance for at least two storms to impact New England in the next ten days.
The first storm comes late Tuesday, extending into Thursday, delivering mostly light snowfall rates periodically through that timeframe. But even light snow over a couple of days adds up, bringing two to three inches for many by Wednesday evening. Three to six inches are expected in western New England Mountains and closer to an inch for much of Maine, though some additional light accumulation will fall Wednesday night and Thursday.
A break in the action heading into the weekend will only come because such cold and dry air takes over for a few days. The next storm chance enters Sunday night into early next week with a chance of snow and perhaps a rain/snow line closer to the coast. That's a long way out, though. We’ll keep watch on it in our exclusive First Alert 10-day forecast.