Late week winter storm possible in interior New England

Amid a changing hemispheric pattern and active jet stream pattern, forecast models have begun to hone in on the potential for a late-week winter storm across New England, particularly interior locations. Despite the presence of a warm antecedent airmass and a relatively progressive-natured pattern (both of which will be discussed as mitigating factors below), the potential does exist for a winter storm that would impact interior locations of New England as an energetic disturbance drives southeastwards into the Northeast US late week.

Forecast models have responded to the development and energy of this disturbance as a reaction to a storm system in East Asia — yes , East Asia. We speak often about how weather patterns in the Pacific Ocean affect our area as well, and this time is no different. A deep storm in East Asia has built ridging into Alaska, which has shunted this disturbance southeast more quickly and with more energy.

Forecast models are, not surprisingly, struggling with the details of the system itself. These intricate details and local impacts will not be determined for a few days still, as models continue to struggle even with larger details and pieces of energy. However, confidence has recently increased in the overall track of the disturbance aloft, with forecast model ensemble guidance coming into better agreement.

Live near the coast? This isn’t the storm for you. Despite the overall evolution of the storm system being favorable, there are two mitigating factors which will make it very difficult to see wintry precipitation near the coast with this event:

1) The antecedent airmass is quite warm. In other words, the air ahead of the storm system is not conducive for snowfall — which makes it very difficult for coastal locations to see it. A low pressure area, additionally, moves northwards into Southeast Canada before the main low pressure takes over off the coast. This will enhance southerly winds making it very difficult to see wintry precipitation away from the interior areas.

2) The progressive nature of the pattern suggests the storm system won’t have enough time to truly deepen offshore. Often times, if the pattern slows down, even a very marginal airmass can be overcome by dynamic cooling, which occurs when storms produce heavy precipitation and dynamics to cool the surrounding environment. But this pattern is progressive enough that the storm will move quickly northeast, leaving minimal opportunity for dynamic cooling over the marginal airmass.

Accordingly, our confidence is increasing gradually in a winter storm across Interior New England late this week into the early part of the weekend. This event currently looks most likely to be impactful across interior parts of Southern New England, northwards into parts of Vermont, New Hampshire and Maine, where the strengthening storm system could produce heavy snow.

That being said, uncertainty does still exist in regards to the exact track of the storm — and the impacts as well. Stay tuned for more details over the coming days including more details on rain/snow areas and accumulations.