Today’s early morning run of the NAM showed a significant change from the warmer and wetter run of yesterday evening.
Here’s the trend- Intensification of the low pressure system developing on the frontal boundary has increased, while the speed of the system has slowed. As a result, the precipitation starts as rain after midnight, but changes to snow during the early morning hours on Thursday. The NAM shows a few hours of moderate snow, ending about 10 AM. (Areas to the far north and west will have much greater accumulations, as the change to snow occurs much earlier.).
Last night’s GFS still showed a somewhat faster and warmer system, but the trend is towards intensification and somewhat slower speed. The slower speed allows more cold air to enter the area.
The Thursday morning commute looks to be a challenge, as some snow, and cold gusty winds move in.
Still too soon to predict specifics regarding accumulation and exact timing.
Saturday 8 AM Update: The upper air disturbances mentioned are producing snow flurries in our area this morning, not predicted by the models. Some bands of snow flurries are moderate, especially south of PHL.
Typical winter weather is expected this weekend. A cyclonic flow of cold air will be with us for most of the weekend, but temperatures will be slightly above average.
Saturday will be windy and cold. Upper air disturbances will result in considerable cloudiness from late morning through much of the afternoon. High temperatures about 43.
Sunday will continue somewhat breezy and there will be more sunshine than Saturday. Highs about 44.
No snowstorms in short term. Some precipitation possible Tuesday into Wednesday and a more significant system possible next Sunday.
