On a normal late-January day the average high should be 40 and the average low should be 25. On this Friday however, at Philly International our low was 8 (record low was 0 set back in 1882) while our high was a "balmy" 19! We failed to reach 20 degrees AND we've been below the freezing mark since Monday!
Overnight Friday clouds will increase with a clipper system on the way for Saturday, but not before lows dip down in the lower teens(and with a light southwest wind that will create a wind chill in the single digits!).
Saturday as I mentioned will be cloudy with snow showers; there will just be a coating to perhaps an inch in Center City, but well north and west there may be a couple of inches of snow. There is a Winter Weather Advisory in effect in those areas from 10am-5pm.
We'll have late clearing overnight with lows in the lower 20s and this will lead to Sunday being cold once again thanks to another reinforcing shot of Arctic air. Highs will just rise a couple of degrees. We'll cloud up overnight into the Monday, and guess what happens?
So from the lower 20s we'll rise to eventually the lower 40s by sunrise; this will be accompanied with some rain, but as a cold front works through by the mid-morning we can see a changeover to snow with little accumulation as temperatures fall in the afternoon.
If you guessed after that cold front pushes through we'll get cold once again, you're correct! Tuesday will only be around 20 degrees despite plenty of sunshine and overnight lows will be on either side of 10. Wednesday as that cold front is still offshore is spawns an area of low pressure along the Carolinas and can lead to a wintry mix across the Southern Delmarva; for us we'll just have clouds with highs in the middle 20s. On Thursday we'll remain in the middle 20s, but as a cold front approaches from the west we'll have a chance for some light snow.
You can see the rest of the seven day forecast(in pictures) any time at www.scottderekwx.com/forecast.html.