A quick update.  Latest NAM shows a significant snowfall for the PHL area, starting after midnight Wednesday and continuing into the morning on Thursday.  Temperatures for the storm have continued to drop, the low pressure system in more intensified and slower. Current QPF values are over 0.60 inches water which translates into over 6 inches of snow.

This situation continues to change.  Stay tuned.

The models have been incredibly consistent with the forecast of precipitation moving in before daybreak on Saturday.

Update:  Light snow moves in after 1AM Saturday.

Expect some light snow before daybreak Saturday morning, but temperatures in the upper atmosphere warm up rapidly and changeover to sleet and freezing rain should occur in the early morning.

The big questionmark is how fast surface temperatures warm up.  The models always forecast too fast a warmup at the surface, so it is possible that much of Saturday morning will have a prolonged period of freezing rain and icy conditions, especially north and west of the city.

A more accurate handle on the vertical temperature profile for Saturday morning won’t be available until Friday evening.   Stay tuned.