Thursday, January 20, 2011

Snowfall Forecast for Late Thursday into Friday Morning





With the latest computer model guidance in, I am ready to put out a preliminary snowfall map. A clipper system will approach from the west. As it does so, a coastal low pressure area will form offshore. The models over the past 12 to 18 hours have indicated that this low pressure area will not intensify rapidly until the storm is off the coast of New England. The models have also indicated this low pressure area will be further offshore. The result is a colder storm and I do not see mixing being a factor in coastal sections of Southern New Jersey or Central New Jersey. This will be a snow event. If any warm air was to make it into the region, it would be along the very immediate coastline.

The other thing going against substantial snowfall at this hour is the fact that this is a 6 to 8 hour window of snowfall. The snow will begin between 10 p.m. and 12 a.m. on Thursday and shut off from west to east on Friday Morning just before or during the morning rush hour.

At this time, I do not believe there will be more snowfall to our north and west. I see the heaviest precipitation actually occurring over Eastern Long Island down through Eastern Delaware. The coastal counties of New Jersey are in the middle of the corridor of heavier precipitation. The models are indicating the most precipitation in New Jersey.... with 0.10 to 0.25 available in much of the state according to the NAM model and 0.25 to 0.50 inches available according to the GFS. The latest NAM is not too aggressive with amounts south of the Atlantic City Expressway (showing just a trace of snow to a coating). I think the latest 00z NAM is too dry and I am looking at the prior 12z and 18z runs which is more in line with the GFS from 00z. In fact the GFS output for New Jersey on the 00z run is a bit more than 12z and 18z.

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