An area of low pressure currently in the Plains this afternoon will bring a major winter storm to the region tomorrow night on through early Thursday morning with significant snow accumulations, poor visibility, strong winds, and coastal flooding.
The storm will initially track towards the Ohio River Valley tomorrow evening with increasing clouds and a few rain and snow showers. This low pressure system will redevelop off the Delmarva Peninsula on Wednesday morning with rain and snow rapidly developing throughout the region in time for the Wednesday morning rush hour.
Along the immediate coast of New Jersey, some warm air will mix in to start the precipitation as rain before strong lifting cools the atmosphere to change the rain over to snow. As a result, snow accumulations in these areas will be in a lower range.
For the rest of the Philadelphia and New York City metropolitan areas, heavy snowfall can be expected. The snow will feature convective banding which will lead to a wide range of snowfall accumulation, but a base of 6″ is expected. Some rain and sleet may mix in at times as well. There will be the potential for snowfall totals to go over 12″ in a few locations due to mesoscale banding impacts.
The snow will taper off to the west with a sharp cut off over easter Pennsylvania from the heaviest snowfall to liter snowfall thus the lower snowfall amounts.
In addition to the snowfall, strong winds are expected to impact the region as the low pressure system rapidly intensifies with sustained winds by late Wednesday morning between 15 to 30 mph with gusts over 40 mph at times. The strong winds will produce poor visibility, power outages, and downed trees.
Another concern will be coastal flooding, especially for locations like Long Island where the current sea levels are already elevated from the previous storm. While this storm will exit by Thursday morning, coastal flooding concerns will be elevated on late Tuesday night and continue on through Thursday.
The worst impacts from this storm will be from 10 AM to 11 PM Wednesday with heavy snowfall, poor visibility, strong wind gusts, and coastal flooding.
If the low pressure system tracks closer to the coast, warmer conditions will be found on the coast, reducing snowfall potential. The storm may also track further east, but this potential did not show up in any current guidance.