Wednesday, December 07, 2011
Timing Tonight's Changeover
Heavy rain should gradually nudge towards a steady thump of snow over the next few hours, starting in the Poconos and transitioning towards lower elevations as we work towards the 11 PM - 2 AM timeframe.
Temperatures will being to slide into the 40's in the early evening hours, likely dropping into the 30's west of the city towards 10 PM, with 30's into Philly by Midnight or 1 AM. Higher resolution modeling (shown below) suggests a changeover from rain to snow to occur into Lancaster and Berks Counties, as well as the Poconos, by 11 PM (if not a touch earlier in the Poconos). The change from rain to snow could occur into Philadelphia by 1 or 2 AM (particularly the higher elevated parts of the city). A two to three hour shot of snow is expected across the Philadelphia suburbs in Pennsylvania, as well as north of I-195 in New Jersey. That shot of snow may not last quite as long across the city and South Jersey but flakes will fly as far south as the Airport and it's possible a coating could accumulate into the heart of the city.
Our accumulation forecast for the region still holds -- lower elevations north and west of the city will see an inch or two, higher elevations will pick up more. The city itself will see a coating of snow, with maybe an inch in Mount Airy.
We'll provide another update later this evening regarding progress on the colder temperatures.
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