WINTER WEATHER FORECAST

Update Sat @ 11:47 AM — The snow should be ending in the immediate PHL area by 1 PM, later east in NJ.

Here are estimated snow totals based on MRMS data (11:1 snow water ratio) as of 11 AM—

MRMS derived estimated snow totals 11:1 snow:water ratio as of 11 AM (Click on image for a larger view.)

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Update Fri @ 11:02 AM — The latest GFS just became available. As is almost always the case, its totals are somewhat less than the NAM—

GFS 12z snow totals White contours are 1 inch increments. (Click on image for a larger view.)

I’m providing this morning’s NAM forecast again for easy comparison—

NAM 12z (Click on image for a larger view.)

My rule of thumb is to average the GFS and NAM for a best forecast.

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Things seem to be coming together, based on the latest Water Vapor image and superimposed NAM/GFS potential vorticity (see explanation below)—

  • Last night's (Thurs) Water Vapor with Potential Vorticity

Update Thu @ 11:16 PM — Quick update. Latest GFS has increased snow totals almost as much as NAM.

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Previously Posted Thu 5:32 PM —

The storm late Friday through Saturday time frame has entered into the range of the high resolution models.

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With the high resolution models coming into the mix, here’s the forecast:

Friday:

An upper air disturbance and cold front will move through. We’ll have light snow break out northwest of the city as early as late morning Friday. Light snow/flurries on and off, mostly north and west of the city. Accumulation a dusting to 1/2 inch. High 34º sd 1.7º NBM model Blue Bell.

Snow starts Friday evening.

Most of our snow with this storm will occur Friday night into early Saturday morning.

Saturday:

Cloudy, cold and WINDY. Snow tapering and ending in the morning but lingering at the NJ shore. High 23.2 sd 2.9º NBM model Blue Bell

Sunday:

Sunny and cold. Windy. High 26.7 sd 2.2º


Earlier Storm Coverage:

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