PHILLY STORM UPDATE – 7:30 AM

The 1AM model runs (06Z) show increased QPF for the hours now through about 6 PM- Over 1.0 inches water falling.

The secondary low pressure is developing south of Long Island, somewhat closer and westward, accounting for the increased QPF.   With the westward development, warmer air is predicted to intrude in the upper levels of the atmosphere at times during the day.  Critical temperatures remain warmer until about noon here in PHL, delaying the transition to snow.  Still expect snow to mix in but very uncertain about grassy accumulations.

I’ve been hanging my hat on the NAM model which has been a bit of an outlier, a somewhat colder forecast than some of the other models.   With these latest model run, the NAM is even a bit warmer, so I think the 2-4 inch grassy surface accumulation is wrong now.

Indeed, some of the short range models now show nothing accumulating around here.   I’m hard-pressed to give a number now.

(Indeed, the TV forecasters suddenly dropped any mention of snow accumulation in our area last night and went on the bandwagon with a high wind concern.)

Still expecting strong winds, especially in the afternoon.

The next model data becomes available about 9:45 AM this morning.   I’ll update then.