Technical Discussion

Synopsis…

A ridge of high pressure centered over the southeast US with the surface high pressure centered over the northeast will mean pleasant weather for today and tomorrow.  Another cold front will pass on Wednesday and bring scattered thunderstorms to many or all areas of PA.  Then another system moves into the region on Friday.

Short-term (Mon. – Wed.):

Skies will be generally clear for Monday and Tuesday with fairly low RH values through the troposphere; Tuesday could be an exception, with the WRF bringing more clouds further south along the warm front than any other model.  We actually accepted the more cloudy solution based on where clouds are now in the southern Great Lakes.  Temperatures will warm from Mon. to Wed. as the surface high pushes offshore and turns our winds from N to S, and assuming warmer temps ahead of the cold front (we went a couple degrees above MOS for Wed. for that reason).  For rain on Wed., it's unlikely we underforecasted it.  CAPE values are pretty high, but the SREF 3-Hour precip is not indicating much rain.

Long-term (Thurs. – Fri.):

The GFS has a stationary front made from Wed's cold front and the next system's warm front draped across PA, and with it rain on Thursday.  Other models are drier or have the front further to the north.  We compromised and kept skies on the cloudy side, especially to the west.  For the next cold front, we speed it up a bit from GFS to come in Friday and Friday night, and we bump MOS up again by 2-4 degrees for Friday's high.

Scott Sieron