Lancaster is a town couched in history and surrounded by Mennonites. Let’s concern ourselves with the skies above.
At 1253PM, ET, Lancaster was reporting a temperature of 39 degrees with overcast skies. A weak trough moving through the Canadian Maritimes is helping to generate some clouds and flurries in the Appalachians, but there wasn’t enough energy to bring any of that snow to Lancaster, and the tilt of the trough was all wrong for maximizing instability in Lancaster. It will be shuttled off shore by the afternoon, and a narrow upper level ridge will build overnight.
That weak ridge will lead to high pressure and a pleasant day tomorrow. It may not warm as substantially as it will in the Ohio Valley thanks to geographical influences, but it will be dry tomorrow in Lancaster. A less favorable trough will set up for Sunday, one conducive for drawing moisture north from the Gulf Stream. Heavy rain will be possible in Philadelphia, but where it will be cooler, there will be snow. A weakly developing low off the Delmarva will do enough to start importing cold air as far to the southeast as Lancaster, and accumulating snow seems possible for Lancaster Sunday afternoon and evening, though as the surface system develops, it will start to cycle in dry air and cut off precipitation shortly after sunset.
Tomorrow – Sunny, High 30, Low 13
Sunday – Rain changing to snow in the afternoon, with about an inch of accumulation possible, then clearing late, High 37, Low 23
TWC: Tomorrow – Mostly Sunny, High 32, Low 16
Sunday – Rain, High 40, Low 26
AW: Tomorrow – Mostly sunny and cold High 29, Low 11
Sunday – Not as cold with periods of rain High 42, Low 23
NWS: Tomorrow – Mostly sunny High 29, Low 10
Sunday – A chance of rain and snow. Cloudy High 42, Low 26
WB: Tomorrow – Mostly sunny, High 28, Low 10
Sunday – Cloudy with a chance of rain or snow. High 42, Low 25
WN: Tomorrow – Mostly Sunny High 30, Low 10
Sunday – Mostly Cloudy with Chance of Light Wintry Mix High 43, low 27
FIO: Tomorrow – Mostly cloudy starting in the afternoon, continuing until evening. High 28, Low 14
Sunday – Mixed precipitation until afternoon. High 41, Low 28
After I mentioned yesterday that there is a new model upgrade, I sort of went against guidance. I went colder and snowier. The snow isn’t really counter to what many people were thinking, but the cooler temps on Sunday is. This is going to be a fun one to watch. Speaking of fun, check out this nifty satellite image. Those banded clouds are the result of gravity waves, caused by cold air rolling over a stable environment.