Tuesday Night Technical Discussion

Synopsis:

High pressure will continue to dominate over New England for the middle of the week. A warm front associated with a low-pressure system to the west will begin to push north through the state Wednesday night into Thursday and bring a chance for scattered rain showers for the northern half of the state. A cold front will follow in the wake of the warm front and make its way east across the state, early Friday, which will provide wide spread rain showers for the entire region before high pressure returns for the end of the weekend.

Short Term: (Tuesday night through Wednesday night)

Short waves just to the north and south of the state will provide a slight chance for scattered showers tonight in those respective areas of the state, as well as eastern counties. Lows will be warmer than previous nights with temperatures ranging from mid 30's in northern counties to mid to upper 40's in the extreme southern portions of the commonwealth, indicated by the 18Z 12km NAM. A chance for fog in the lower Susquehanna valley will be present Wednesday morning. High-pressure remains over the region Wednesday before it moves off the coast and a warm front approaches from the south late Wednesday night.

Long Term: (Thursday into the weekend)

As the warm front makes its way north across the state, scattered showers will be possible Thursday morning, especially for the northern and northwestern counties. The low-pressure system associated with this warm front will move to our north late Thursday night into Friday and the attached cold front will bring rain showers for the entire state. The 18Z NAM gets the precipitation in the far western counties by 3Z, while the 18Z GFS and the 21Z SREF keep light precipitation over the majority of the state after the passage of the warm front and before the cold front passage. The front will move quickly and exit the state by the afternoon, providing clear skies and cooler air via cold air advection in the wake of the cold front. A secondary cold front and trough will move into the region Saturday evening bringing colder air and a northwest flow off the lakes. This will provide scattered lake effect rain and snow showers for the northwestern counties Saturday evening into Sunday. High pressure will return for the beginning of the workweek and warmer air will follow.

~ A.J. Herbert