John Homenuk

Rough PM commute likely with snow, sleet expected

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A storm system developing over the Central United States will shift northward today, bringing enhanced lift for precipitation and forcing the development of snow from southwest to northeast throughout the area. As this lift shifts northeastward, snow will become steadier and heavier later this afternoon throughout the area. This snow will be falling as a result of increased lift for precipitation, owing to an increased southerly flow in the mid levels of the atmosphere as a result of warm air advection.

This warm air in the mid levels will continue to shift northeastward from the Mid Atlantic into the Northeast States, shifting precipitation from snow to sleet across much of Northern NJ and NYC by later tonight. In the low levels, however, cold air will remain stout — creating the potential for not only sleet, but ice accretion as well if the depth of the mid level warm layer becomes wide enough to support freezing rain. This will create treacherous conditions on roadways tonight across Northern NJ and the suburbs of NYC in SE NY and Connecticut.

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Doug Simonian

Two more wintry events possible this week

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An active mid and upper level atmospheric pattern continues to bring storm threats from the Central to Eastern United States this week. After a moderate snowfall event on Sunday Night into Monday, eyes will turn to two more potential winter weather events, both of very different nature, during the middle part of this upcoming work week. Both have the potential to bring snow, sleet, and ice accumulations to much of the forecast area.

The first threat will come Tuesday Night into early Wednesday Morning. A classic “southwest flow event”, as meteorologists often refer to it, will transpire throughout the Northeast United States. A low pressure system will be well to our north and west — over Canada — drawing in southerly winds and warmer air, but low level cold air over the Northeast will hold on long enough to allow for a period of snow.

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John Homenuk

Multi-wave winter weather event possible next week

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A multi-wave winter weather event is increasingly likely to unfold during the early to middle part of next week across a large majority of the Northern 1/3 of the United States, initially in the Great Lakes and then northeastward into New England. The exact area where this winter weather potential sets up obviously remains highly uncertain. Forecast models have been extremely inconsistent in handling mid and upper level features which will eventually have major impacts on the sensible weather experienced by many. But in this case, there are clues in the meteorological pattern that point to the answers to some of our questions. Instead of looking specifically at forecast models and their trends, we can begin to look for answers to our questions in the hemispheric pattern. 

The winter weather threat traces its roots back to the total degradation of the West Coast ridge and positive PNA on along the West Coast of the United States into British Columbia. Inherently, this is a bad sign for snow lovers on the East Coast Any time we degrade a PNA ridge there is a positive mid and upper level height field response to the east of that over the Southeastern United States. In fact, the collapse of a PNA ridge can bring a response all the way into the Western Atlantic. As the amplified pattern out west collapses, the mid level jet collapses east into the Untied States and allows for the flow to enhance further to the east. So not only does the Southeast Ridge suddenly gain amplitude, but the pattern becomes more progressive over the Great Lakes and Southeast Canada — working against snow chances in the East. 

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Doug Simonian

PM Update: More cold, but what about snow?

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After another Arctic day yesterday, today feels tropical in comparison with temperatures in the mid 30s. Is this a sign that winter is losing its grip? Not quite yet.

Several more low temperature records were broken yesterday. For more perspective on how cold it has been, check out the article we published this morning. While widespread record cold is likely done, we may have another night or two left of single digit cold, which is still truly remarkable for this time of year. Overall, below average temperatures and chances for snow will continue for the next 7-10 days.

The first chance for snow comes tomorrow. A snowstorm is developing in the deep south, and is expected to give parts of North Carolina and Virginia up to a foot of snow. Usually, snowstorms of this variety do not come far enough to hit our area, and this is expected to be the case. Having said that, storms that develop near the Gulf  tend to come in a bit further north than forecast (see the cold, 3-5″ of fluffy snow we got last Monday night into Tuesday). These southern waves tend to pump up a lot of heat and moisture which give a feedback effect to amplify the pattern for them to come a bit further north than they normally would.

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