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Just when you thought it was the first day of spring...

Ed Vallee, head meteorologist at Vallee Weather Consulting LLC., warns of the fourth nor’easter this month — expected to slam into the North East on Wednesday:

“Another coastal storm will take shape Tuesday off the eastern seaboard. Intermittent snow and mixed precipitation will impact the Mid-Atlantic Tuesday then spread into New England Wednesday. Snow will be heavy at times Wednesday into Wednesday night, allowing it to periodically accumulate on roadways despite the higher March sun angle. Snow may impact morning commutes in Baltimore and DC, then impact evening commutes from Philadelphia to Boston Wednesday with low visibility and snow covered roads.

Coastal flooding, gusty winds, and heavy, wet snow is expected which, in tandem, may lead to power outages in some locations. Snowfall will wind down from southwest to northeast Wednesday night.”

The National Weather Service (NWS) issued winter storm advisories, warnings, and watches for most of the Ohio-Valley, Mid-Atlantic, and North East up to Boston, Massachusetts (as of Tue, Mar. 20, 2018 at 7:50:08 am EDT) for Wednesday into Thursday.

“The fourth NorEaster for this month is expected to bring up to a foot of snow along the spine of the Appalachians, across northern New Jersey, and into the lower Hudson Valley of New York during the next couple of days,” said NWS.

According to the European Centre for Medium-Range Weather Forecasts (ECMWF), the heaviest snowfall totals will be along parts of the I-95 corridor on Wednesday, which could severely impact commutes from Baltimore to Washington, D.C in the morning and Philadelphia to Boston in the evening.

However, Vallee criticizes the ECMWF model and thinks snowfall totals could at lesser degrees near metro areas.

“10:1 ratio maps are going to be too high in this event: snow will melt on paved surfaces today and Wednesday in most metro areas. Best chance for accum. snow on pavement will come Wednesday evening in NYC into New England. Bust potential very high with this system.”  

Meteorologist Steven DiMartino, the operator of NY, NJ, PA Weather, provides a detailed forecast for the upcoming weather event. DiMartino’s analysis suggests “many locations will have snow on the grass but only slush on the roadways and teated surfaces, even in the heavier snow regions.”

A weakening area of low pressure will pass to the south of the region today with a mix of snow, sleet, and rain expected through this evening. Little if any snow accumulation is expected from this first wave of precipitation. Winds will be from the northeast at 10 to 20 mph, increasing to 15 to 25 mph this evening. Temperatures will rise into the mid to upper 30’s for highs this afternoon.

Periods of snow, sleet, and rain showers can be expected tonight through tomorrow morning leading to slick and icy roadways, especially where untreated. Winds will be from the northeast at 15 to 25 mph with gusts over 30 mph at times. Temperatures will fall into the lower 30’s for lows throughout the region.

A second low pressure system will redevelop off the southern Mid Atlantic coast tomorrow morning and then track through the coastal waters towards the 40N/70W benchmark while rapidly intensifying. As this low pressure system intensifies, the precipitation will become moderate to very heavy. Bands of intense snowfall will develop throughout the region from 2 PM to 8 PM tomorrow. In these snow bands, snowfall rates of 1″ to 3″ per hour are possible. Meanwhile, sleet and rain will mix in with the snow making for icy conditions where sleet could become a dominant precipitation type. Snowfall accumulations throughout much of the region will range from 4″ to 8″ with areas of 12″ or higher. The wide range of snowfall totals will depend on the precipitation type and location of intense snow bands. If more sleet mixes in for a location, snowfall amounts are likely to be around 4″ but 1″ to 3″ of sleet would be possible. If more snowfall than sleet develops than around 8″ is more likely. Further, if a location happens to remain over an intense band of snowfall with enhanced snowfall rates, than some locations will potentially go over 12″. There is also potential for some urban areas that the snow will have a difficult time accumulating as surface temperatures will be marginal. Aside from the heavy precipitation, strong winds will be a threat with sustained northeasterly winds at 15 to 30 mph with gusts between 40 and 70 mph. These strong winds and gusts will lead to visibility below 2 miles, downed trees, wind damage, and power outages. Further, coastal flooding will be a threat with tides 1 to 3 feet above the astronomical high tides. Temperatures will range from the lower to mid 30’s.

Travel is NOT suggested between 2 PM and 8 PM tomorrow due to these conditions.

The storm will exit on Thursday morning with some lingering snow showers followed by clearing skies towards the afternoon. Winds will be from the northwest at 15 to 30 mph with gusts over 40 mph. Temperatures will range from the mid to upper 20’s for lows and lower to mid 40’s for highs.

High pressure will be in control for Friday on through Monday with clear skies to scattered cloud cover. A storm will pass to the south of the region on Sunday that may lead to a few isolated showers over extreme southern New Jersey. Temperatures on Friday will range from the mid 20’s for lows and upper 30’s to lower 40’s for highs. Temperatures on Saturday will range from the lower to mid 20’s for lows and lower to mid 40’s for highs. Temperatures on Sunday will range from the mid 20’s for lows and lower to mid 40’s for highs. Temperatures on Monday will range from the mid 20’s for lows and lower to mid 40’s for highs.

Here are the latest tweets from Social Media Meteorologist who have commented on the upcoming weather event: 

“Nor’easter Number 4: NWS “adjusted” forecast snowfall amounts for New York City — now 14-16″ with almost 15″ expected in Central Park. 12-inches or 1-foot in Boston,” detailed Ryan Maue, Meteorologist & Atlanta Bureau Chief @weatherdotus.

“It’s Nor’Easter # 4!! Here’s The Latest Expected Snowfall, Up to A Foot Is Possible In Some Local Spots,” said Bill Evans, Senior Meteorologist WABC-TV New York City.

“Good Tuesday morning! Spring begins officially at 12:15pm but… we’ve got more winter on the way. Winter storm watches and warnings are up for tomorrow’s #noreaster Turn on #wcvb until 7am for the timeline and of snow, wind and coastal flooding,” said Cindy Fitzgibbon, Meteorologist at WCVB (Boston).

And here's how much snow you can expect to wake up to early Thursday AM...

Frank Giannasca, a Weather Channel senior meteorologist, believes there is a silvering lining to the fourth nor’easter expected to punish the East Coast mid-week: it will probably be the last of one of the season…

“The reason for the nor’easters is a pattern that we’re in right now where we’ve had some blocking in the high latitudes,” he said. “Oftentimes, when we have this blocking, it tends to produce a pattern of cold air over the Eastern United States that allows the storm track to move around the country and develop strong storms in the East Coast.”

“As for how long that’s going to stick around, for at least the time being, this might be the last one, at least from what I can see.”