WINTER WEATHER UPDATE SUN 4:15 PM

This afternoon’s NAM model (yes, the model run I would prefer not to rely on) is in.    QPF has increased to 1.26 inches water. Precipitation tapers off around 2 AM.  So, some heavy rain, even some convective rain (thunder) possible with the mix of sleet and snow.

The rain we have will mix with sleet and snow.  And it may be all-snow for a period.

No change in my forecast. The upper atmosphere remains too warm to support all-snow in much of the immediate Philadelphia area.  While some snow will fall, accumulations will be highly limited by a mixing in of sleet and rain.

The areas (in green) in the graphic below will also have significant sleet and rain, reducing the snow accumulations considerably.  If you look back at the postings of the past several days, this white line is further north and west than previous forecasts.

critical temp
White line- Critical temperatures. Northwest of the line mostly snow,  Southeast of the line, a mix of sleet, snow and rain.

Combined with temperatures that are at or above freezing at the surface, I don’t expect snow accumulations to be very impressive in the areas in green above.

Philadelphia, south NJ (east of the Delaware) will have minimal accumulation. Immediate suburbs north and west about 2-3 inches of heavy mixed snow and sleet, increasing to 7-10 inches in the far north and west. The further north and west, the more accumulation.

It’s not that you won’t see some snow in these green shaded areas, but how much can really accumulate? I guess we’ll see.