On this first day of 2014 we had sunshine mixed with clouds as highs reached 41 at Philly International; guess what? That's EXACTLY where we should be for the 30-year average high! It's great that we are average, but it still stings a little that the average high is that cold; I hope you enjoyed that high temp today because by the weekend you may reminisce about the "warmth" from today!
It's no surprise that we have snow on the way as the National Weather Service in Mount Holly placed the region under a Winter Storm Warning from Thursday evening until Friday morning. Now we could use some snow as we are two tenths (0.2") below average for the year-to-date(come on....it's a bad first day of the year joke!); we'll get our share as we have a low forming along the Gulf of Mexico that will phase(come together) with an area of low pressure across the Plains to provide a plowable snowfall.
Timing is everything of course and although precipitation will begin during the day Thursday it will mostly be rain as highs will be above freezing EXCEPT for higher elevations where the temperature will stay below freezing. The moisture will come from the coastal portion of the low as that slides to the northeast, but then Thursday night after dinner(7pm or so) as cold air pushes in we will see a changeover to all snow. I am going with between 2-5" of snow across the Philly area because by the time the cold air moves in we will still have surfaces above freezing; this means it will take a few hours for snow to stick to roads and warmer surfaces(cars and grass shall accumulate pretty quickly). NOW WHEN THIS OCCURS we will have temperatures into the 20s and so anything wet will freeze and that shall turn everything to ice!
Behind these systems will be very cold air as temperatures during the day will just be in the 20s on Friday, but the issue will be Friday night as the heart of the cold air will be on top of us. Lows will get down in the lower and middle single digits(and that's not even factoring a wind chill!); I mentioned this yesterday, but in case you missed it the record low for Friday is -3 set in 1879 and the record low for Saturday is 23 set in 1918. Now why did I add both days in? It's because daily almanacs are recorded from 12:00am-11:59pm and depending on how quickly we cool off overnight(especially with fresh snowpack on the ground) it could happen before the 11:59pm cutoff will be something to watch as records go from 12:00am-11:59pm.
Of course you can check out the 7-day forecast any time at www.scottderekwx.com/forecast.html.