PM Update: Winter weather set to impact the area

A strong cold front, which crossed the region earlier today, is ushering in a much colder airmass — and a record breaking arctic airmass to the Central and Western United States. A developing disturbance along the front will touch off more precipitation in our area later this evening into Saturday. The dramatic cold front has not yet delivered arctic air to the East Coast, but the arctic gates have opened over much of the Midwest, Northwest and North-Central United States.

Some fascinating numbers evidencing the strength of the cold front include:

1) A minimum temperature reading of 28 degrees in NW Mississippi, and a maximum temperature reading of 84 degrees in SE Mississippi.

2) Temperatures in the upper single digits and lower teens as far south as Oklahoma, Texas, and Arkansas, where several inches of snow has fallen.

3) A minimum temperature reading of -23 degrees in Montana, and a maximum temperature reading of 87 degrees in Florida. A 110-degree temperature gradient across the country!

RAP analysis on Friday evening, showing a dramatic cold front over the Eastern US and an arctic airmass over the Central and Western US.

RAP analysis on Friday evening, showing a dramatic cold front over the Eastern US and an arctic airmass over the Central and Western US.

Closer to our area,  temperatures are merely chilly and not cold as the core of the arctic airmass still remains to our west. Compared to where we were yesterday, however, temperatures have been plummeting both aloft and at the surface. This will cause an interesting scenario which may eventually lead to the development of frozen precipitation for a period of time — especially across the interior and suburbs. Accordingly, the National Weather Service has issued Winter Weather Advisories across elevated and interior areas of Northwest New Jersey, Southeast New York and Interior Connecticut, where light snow accumulations are expected tonight along with a trace to up to one-tenth of an inch of ice.

Today's 18z NAM model, valid for 1:00am tonight, showed snow and sleet moving into the interior locations of our area, with primarily rain in NYC and coastal regions. Image credit goes to weatherbell.com.

Today’s 18z NAM model, valid for 1:00am tonight, shows snow and sleet moving into the interior locations of our area, with primarily rain in NYC and coastal regions. Image credit goes to weatherbell.com.

Through tonight, light rain is likely to impact the area during the evening commute. In the city, liquid precipitation is expected through much of the overnight. By early morning across the interior, the transition may begin to occur before precipitation ends. Light accumulations of snow are possible, but in general weather related hazards are expected to remain minimal. Urban areas, including New York City, may see a period of snow as well — but no accumulations are anticipated.

More winter weather forthcoming on Sunday

With the cold front pushing just off the coast and east of the area on Sunday, colder air will have settled into the region but will remain more stubborn to our north over New England. An approaching mid-level disturbance will trigger a weak low pressure system, which is forecast to shift from the Ohio Valley to off the coast of the Mid Atlantic from Sunday into Monday. Warm air advection (push of warm air in levels of the atmosphere) is likely to occur throughout the mid levels at a fairly rapid pace as precipitation approaches the area, but a colder surface could mean a period of frozen precipitation across the interior.

Owing to the close proximity of the high pressure system, dry air will initially preclude any steady precipitation. Even once precipitation begins, it likely will be light and scattered in nature. By the time the moisture becomes a bit more abundant, temperatures will have warmed closer to the coast. This suggests that any snow or sleet that falls should transition to rain within a couple of hours or so — with minimal accumulations that will eventually wash away in periods of rain. But over the interior areas and higher elevations, colder temperatures will hold on a bit longer, leading to some snow and sleet accumulations on Sunday Night — the amounts depending mainly on the depth of the cold air and the speed at which warm air moves northward. We are expecting this to be another nowcasting situation, so stay tuned for updates as the weekend approaches.

Winter weather forecast, valid beginning Sunday and continuing into Monday. This map does not include the potential light snow/wintry weather on Friday evening and Saturday morning.

Winter weather forecast, valid beginning Sunday and continuing into Monday. This map does not include the potential light snow/wintry weather on Friday evening and Saturday morning.

As it stands now, periods of snow and sleet are likely away from the coast and city on Sunday Night, eventually transitioning to rain before precipitation ends. Some light accumulations are possible, and becoming likely, across these areas.

By the beginning of next week, the multiple disturbances will shift east/northeast of the area, allowing a frigid airmass to take full control of the forecast. High pressure building in will secure the cold — with temperatures likely falling into the teens and possibly single digits in many areas overnight next week.

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