Technical Discussion

Synopsis…. 

A storm system will stall over parts of New England and eastern Canada, allowing for slightly unsettled conditions to prevail over most of the state for the first half of the week.  Expect a chance of snow showers every day and continued cold conditions.  The Laurel Highlands and northwestern regions of the state will have the greatest opportunity for significant snowfall accumulations, due to the high elevation and lake-effect snow occurrences.

Short-Term…. 

The models all show the moderately strong low-pressure system that will remain over New England and eastern Canada through Tuesday and associated swath of moisture that dips down nearly into Pennsylvania.  The disturbance will help create and maintain a deep northwesterly flow over western portions of the state.  The winds are aligned appropriately to initiate convection over some of the Great Lakes, which will result in significant lake-effect snow events that will affect northwestern regions of the state.  Additionally, orographically-driven snow showers will affect much of the Laurel Highlands into Tuesday.  The 1200 UTC run of the GFS shows snow showers beginning to affect western portions of the state later this evening and affecting regions towards central Pennsylvania as Monday progresses.  The GFS has the snow showers tapering off by late Tuesday, with only a few lingering bands of showers in the western regions after that.  The 1200 UTC run of the WRF shows similar, except that it is projecting heavier bands of snow on Monday in extreme northwestern regions.  The1500 UTC run of the SREF precipitation ensemble shows similar distributions of snow showers, but has them significantly lingering around the state until late Wednesday night.  We forecasted accordingly.

Long-Term…. 

The models all project high pressure building into the state on Wednesday and Thursday, halting the lake effect snow and other snow shower activity briefly.  It looks like the state will stay relatively precipitation free, especially on Thursday, but there will be still be some low-level moisture remaining that will allow for some clouds over portions of the state intermixed with a bit of sun here and there.