John Homenuk

Southeast ridge will flex its muscles late month

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All things considered, after much conversation and discussion, meteorological winter came in cold and active during the month of December. Multiple shots of arctic air and several winter weather events, particularly in the interior, have given us a December much different than the past few years, when warm air dominated the Eastern United States’ weather pattern. That very same cold and active pattern looks likely to take a hiatus over the next few weeks.

The hemispheric pattern is undergoing changes once again — this time, pulling back the reigns on an active, amplified pattern which saw polar air drop into New England last week. This time, the stratospheric polar vortex will tighten and strengthen near the North Pole, pulling back much of the arctic air and reforming the vortex near its usual whereabouts. For much of the Northeast US, this means that arctic air will gradually become less available over the next two weeks.

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John Homenuk

Impactful winter storm expected Saturday AM

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Colder trends, discussed at length over the past few days, have come into better focus over the past 12 to 24 hours, with mesoscale forecast models and short term weather observations lining up with those ideas. The result will be an impactful winter storm throughout much of the area — save for Southern New Jersey and some coastal locations — with the focus on interior Northern New Jersey, Southeast New York and Connecticut.

As always, our latest products are available and break down the threat for snow, freezing rain, and sleet throughout the area. We invite you to watch our latest Premium Discussion video, which includes a narrative of images and ideas with details of how we compiled our forecast.

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John Homenuk

Threat Analysis: Weekend winter storm

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A well discussed storm system — with winter weather potential — is heading towards the Northeast US this weekend, in the wake of a brutally cold airmass associated with the polar vortex in the troposphere. This storm, however, will come with a vast amount of warm air advection — which occurs when warm air moves in multiple levels of the atmosphere. In this case, southwesterly winds are driving the storm system towards the Northeast as the polar vortex departs.

The resulting storm system will be one of transition, with a cold airmass in place to start, followed by a moist and warm airmass as the storm begins its departure. The transition itself will occur with quite a bit of complexity, and interior locations are likely to see a impactful winter storm on Saturday, particularly in the morning hours. Nearer to the coast, a change to rain should occur relatively quickly, alleviating widespread impacts.

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John Homenuk

Weekend storm system will start wintry in Northeast

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An arctic airmass will drive southeastward from Canada and into the Northeast United States late this week, bringing with it the coldest temperatures in quite some time. In fact, the arctic airmass is part of the polar vortex — yes that one which we discuss all too often — a piece of which is dropping southward into New England. This isn’t necessarily unusual in winter, but it certainly is this time of year — some of the temperatures being modeled at 850mb (5000 feet) would challenge record lows for this time of year.

Nevertheless — the polar vortex swinging through will, after it brings some brutally cold air, begin a quick departure. This is occurring mainly due to a lack of high latitude blocking. In other words, there is no feature to “keep” the polar vortex from shifting away, and back to where it typically stays. There was an impetus to bring it here, the Alaskan ridge which we discussed at length the past several weeks.

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