North Central PA has the ability to be a tricky forecast, because it is squeezed between the Atlantic and Great Lakes, all while nestled in the folds of the Allegheny Mountains. Tricky!

At 954PM, ET, Williamsport was reporting a temperature of 55 degrees with clear skies. The cool temperatures, valley location and clear skies are all ingredients that will lead to overnight fog.
A stout ridge lays over the Mid-Atlantic, despite a strong trough attempting to move in from the northern Plains. Eastern Pennsylvania will remain clear and fairly sunny through midweek while the boundary and trough dissipate and stall, respectively. Flow will become more southerly, however, leading to a warmer day on Wednesday in Williamsport.
Tomorrow – Mostly sunny, High 73, Low 48
Wednesday – Mostly sunny and warmer. High 81, Low 54

TWC: Tomorrow – Partly cloudy skies. High 74, Low 46
Wednesday – A shower or two possible early with partly cloudy skies in the afternoon. High 81, Low 55

AW: Tomorrow – Mostly sunny in the morning followed by sun and areas of high clouds; pleasant with low humidity HIgh 74, Low 46
Wednesday – Sun through high clouds High 79, Low 53

NWS: Tomorrow – Patchy fog before 9am. Otherwise, sunny, High 74, Low 45
Wednesday – Areas of fog before 10am. Otherwise, mostly sunny, High 81, Low 52

WB: Tomorrow – Patchy fog in the morning. Sunny. High 73, Low 50
Wednesday – Patchy fog in the morning. Mostly sunny. High 80. Low 55

WN: Tomorrow – Mostly sunny, High 73, Low 45
Wednesday – Partly cloudy, High 80, Low 52

CLI: Tomorrow – Sunny, High 72, Low 47
Wednesday – Light rain showers, High 79, Low 55

Those smatterings of rain showers are particularly interesting to me. The radar and cloud cover are pretty empty tonight.