Friday 4 PM Update: Latest NAM data maintains ‘cold air damming ‘ in the immediate PHL area.  A more significant ice storm is possible before the changeover to rain.  The next NAM data available about 9:40 PM and I’ll update around that time.

Here’s the latest trends for tomorrow morning’s winter weather–

The trend has been for temperatures in the upper atmosphere and the surface to warm a bit faster.  The latest NAM shows temperatures near the surface to be above freezing by 7 AM in Philadelphia.

So, for Philadelphia, it’s looking like less snow, that quickly turns to sleet and freezing rain before daybreak. It will probably be all rain by daybreak in the city, so any small accumulation of sleet and snow  will be slush early.

Areas to the immediate north and west will get less snow and more freezing rain. Significant icy conditions possible for several hours  after daybreak before changing to all rain by mid to late morning.

The rain will be heavy in the morning, tapering and ending early afternoon.

I’ll update about 9:40 this evening, after this evening’s NAM FOUS data becomes available.

As mentioned last week, the models continue to advertise a warm up around X-mas