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Surge of cold air, first interior freeze this weekend

A winter-like weather pattern across the Continental United States will bring the coldest air of the season to much of the Northeast this weekend. Temperatures are expected to fall below freezing during the evening and early morning hours across parts of the interior on Sunday and Monday mornings, with the first frost and freeze of the season looking increasingly likely in those areas.

The surge of cold air is being enabled by a large upper level trough, which will amplify from Canada into the Northeast States this weekend. As is typical during the winter months, a large ridge over the West Coast of the United States will help cold air dive southward to its east, into the Eastern United States. Temperatures at the surface (where we are) are expected to fall 15 to 20 degrees below normal by Monday morning.

GFS model showing the source of this weekends cold air mass.

GFS model showing the source of this weekends cold air mass.

The source of this weekends cold air? North-Central Canada. While the airmass will obviously modify before it reaches us, this cold air is legit — and forecast models are catching on despite the fact that it is still relatively “early” in the cold season. Low temperatures on both Saturday and Sunday Nights will drop into the 40’s throughout the area — but interestingly enough, mid level atmospheric  temperatures will fall well below zero as well.

This means that with the right radiating conditions (clear skies, light winds), parts of the interior will face the possibility of their first frost and freeze. In fact, forecast models suggest that on Sunday Night and Monday morning, with mid level atmospheric temperatures 4 to 6 degrees below zero (Celsius) and light winds, many areas could fall into the lower 30’s in Northern NJ, Southeast NY and Connecticut. Temperatures are currently expected to stay slightly warmer in NYC and near the coast.

GFS model showing lows in the 30's across much of the interior on Monday morning.

GFS model showing lows in the 30’s across much of the interior on Monday morning.

High temperatures on Sunday and Monday will be quite chilly as well. Behind a cold front, which brings this cold air into the area, northwesterly winds will continue during the daytime hours. These brisk northwesterly winds, also more common in winter months, will keep high temperatures in the 50’s — and a few degrees cooler in the interior and suburbs. We definitely suggest bringing the jacket along this weekend. Sweater weather, if you will.

The good news? While we recommend bringing the plants indoors and taking your first-freeze precautions, this weather won’t last long — for now. The west coast ridge will remain transient, and will roll over to the east by mid-week. This will help kick out the deep trough, and bring moderating temperatures back to our area.

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