(Premium) Weekly outlook and hazards information

A powerful coastal storm will shift east/northeast this afternoon, toward the Northwestern Atlantic Ocean, with lingering impacts expected in our area. This will be especially true for coastal sections of Eastern Long Island, where bands of snow may linger until the evening hours of Monday as the coastal low pulls away. Elsewhere, relatively benign weather will take over with gusty winds in the wake of the storm system — but no further accumulating snow.

Despite the departing storm, there are several other weather events to speak about during the upcoming work week. They begin with a weak coastal storm from Tuesday into Wednesday, and end with bitter cold and a possible coastal storm threat this weekend.

Tuesday/Wednesday accumulating snow threat

A complex atmospheric setup will evolve on Tuesday in the wake of the major coastal storm currently shifting away from the area. A second disturbance, of northern stream origin, will drop southeastward from the Great Lakes into the Mid Atlantic States. This disturbance will eventually reach the East Coast, forming a surface low-pressure area over Mid-Atlantic that will shift southeast of Long Island Tuesday into Wednesday.

Of particular interest is the track and intensity of this low pressure area, with bands of snow expected to develop to its north. Forecast models have come into better agreement during the past 24 hours that this storm will track south of our area — far enough south that any measurable snowfall will be contained to areas south of NYC. But there are still major differences among models in terms of location of banding.

NAM model showing stronger lift and support for banding of snow in parts of NJ on Tuesday and Wednesday.

NAM model showing stronger lift and support for banding of snow in parts of NJ on Tuesday and Wednesday.

The general track of the atmospheric features in the mid and upper levels suggests bands of snow should develop over the Northern Mid Atlantic and move into Southeast PA as well as Southern and Central NJ. These bands will gradually move northeast through NJ, and may impact NYC for periods of time on Tuesday and Wednesday, with generally only light accumulating snow possible.

The steadier snow, farther south, is where more notable accumulations are anticipated. Pinning down the exact location of banding over the next 12 hours will give us a better idea in terms of where the heaviest snowfall is expected — likely on the order of 3 to 6 inches. A snowfall map is expected by 8:00pm this evening.

Bitter cold approaches this weekend

Snow and snow showers will linger after the second coastal system until Thursday, as cold air begins to prepare for a rapid entrance into the Northeastern United States. Back to our north and west, a piece of the Polar Vortex will begin its march southward through Canada. Forecast models agree that it will approach the area by Saturday and Sunday. Benign and cold weather is expected before that (for Thursday and Friday).

As this polar vortex drops southward into the Northeast US from Southeast Canada, models have hinted at the potential for a coastal storm to form. However, given the breadth of the polar vortex piece itself, and lack of southern stream moisture, it appears any coastal storm threat should remain quite progressive — and out to sea.

GFS model showing brutal cold, with 850mb temperatures of -30 C, in the area on Sunday and Monday.

GFS model showing brutal cold, with 850mb temperatures of -30 C, in the area on Sunday and Monday.

Still, bitter cold — the coldest of the season — is increasingly likely to move into our area this weekend. Forecast models show the potential for near zero temperatures in NYC, and below zero temperatures in the suburbs, on both Sunday and Monday. Temperatures like these would be record breaking in many areas.

The piece of the polar vortex will eventually elongate, with brutal cold ending rather quickly after just a few days.

Stay tuned for further updates throughout the week on the aforementioned multiple storm chances and approaching cold air.