As Brian pointed out in our forecast earlier this afternoon tomorrow night is going to be a cold night with a low at the Airport projected to be 17 degrees. It will be the coldest night of the winter season so far, easily besting the 26 we had a week ago.
How cold can it get? This is the NAM computer model prediction for 7 AM on Wednesday morning. The magenta shade are single digit temperatures, with the light blue readings in the teens. If the NAM is correct the entire region will get into the teens, with mid teens into the suburbs (perhaps 13, 14 for a low down to King of Prussia), with lower teens into the Lehigh Valley (maybe 10, 11 at Allentown).