Monday Night Technical Discussion

Synopsis

 

High pressure will continue to build over the state leading to a stronger southerly flow and warmer temperatures across the state. A low pressure system will pass north of PA on Wednesday and it's associated cold front will cross the state Wednesday afternoon bringing scattered rain showers and potential for storms across the region. High pressure will begin to build over the state behind the cold front for the end of the week resulting in clear skies for much of the state. As the high pressure begins to move off shore Saturday and Sunday a slight chance for scattered rain showers statewide will be present for the weekend.

 

Short Term (Monday night thru Wednesday Night)

 

A mean easterly flow off the Atlantic will provide a chance for increasing clouds overnight for the southern half of the state, thus keeping low temperatures near the mid 30's. Skies should remain clear for the northern counties allowing temperatures to drop into the upper 20's overnight. Clouds will stick around for the eastern and central portions of the state for the beginning of the day keeping temperatures in the mid to upper 50's but high temperatures could reach the upper 60's in western PA. Clouds will once again increase overnight keeping low temperatures in the 40's across the state. The 18Z GFS is a little quicker than the 18Z NAM, as the GFS has the precipitation reaching northwestern PA by 12Z, while the NAM has the bulk of the precipitation reaching the state by 15Z. This leads to a large difference in the high temperature as the GFS keeps most areas in the 60's, while the NAM gets central and eastern PA into the 70's. Given ensemble guidance, am currently favoring a mean of the solutions at the moment with some areas possibly reaching 70 on Wednesday. A chance for thunderstorm development looks unlikely, especially for western and central PA due to the clouds ahead of the precipitation cutting off the potential for convection and minimal CAPE. Low temperatures in the lower 30's will follow the passing of the cold front Wednesday night.

 

Long Term (Thursday into the weekend)

 

High pressure will begin to build over the state Thursday morning and continue to do so through Friday allowing temperatures to approach near normal values. There will be a chance for a scattered rain shower across northern portions of the state Thursday night due to a westerly flow off the lakes. As the high pressure begins to move east of the region Saturday afternoon and Sunday, the 18Z GFS has scattered rain showers across the state Saturday afternoon through Sunday, but confidence remains low. Otherwise, conditions look dry for the weekend. 

~Aaron Herbert