Technical Discussion

Synopsis: 

Today, enjoy the unseasonably mild conditions, with temperatures peaking from the low 50s in northern portions of the state to the low 60s in southern regions.  A cold front will pass through the state later in the day and bring more seasonable temperatures for the weekend and a stray shower or two.  In the wake of the front, expect mostly sunny skies and breezy conditions tomorrow, unfortunately with temperatures falling short of today's by up to twenty degrees.  A storm system will approach Sunday into Monday, brining an opportunity for precipitation.

Short-Term:

The 1200 UTC runs of both the WRF and GFS show a cold front passing through the state as today progresses, associated with a low pressure system moving from the upper Midwest up into Canada.  The 900 UTC SREF plumes show very little to no precipitation at all in association with the cold front.  However, the SREF probability fields show up to a 50% probability of precipitation in a narrow band in western Pennsylvania by late this morning, but all other models seem to suggest that any precipitation, if it occurs, wouldn't be significant at all. Visually, the ensemble mean of the 900 UTC SREF NE runs shows a stray shower or two mainly affecting the same western region of the state briefly late this morning into early afternoon.

Long-Term:

The 1200 UTC MOS temperature runs show high temperatures ten to twenty degrees lower tomorrow than those today.  Temperatures will dip particularly low tomorrow night.  The WRF and GFS 1200 UTC relative humidity runs show a dry slot in place until early on Sunday after the cold front passes through, bringing a mix of sun and clouds for tomorrow and increasing clouds by Sunday.  A low pressure system is projected to evolve over the Midwest as the weekend ends, with an associated nice swath of precipitation.  It is too soon to fully accurately predict the precipitation type and amounts, as evidenced by the wide range of precipitation, from a tenth of an inch to nearly an inch, by late Sunday night, as well as the variety of precipitation types, seen on the 900 UTC SREF plumes.