Slight Risk Potential Sunday

The Storm Prediction Center has us under a potential for some severe weather tomorrow as the much complained about front lurks around the region and a disturbance marches east-northeast along the front.   As warmer air slides northward, the atmosphere from the Lehigh Valley on south on Sunday afternoon will become increasingly unstable and thunderstorms will be possible from the afternoon on.  

Computer modeling suggests that the best thunderstorm chances will occur in the afternoon, with particular focus after 2 PM.  The NAM is a bit earlier while the higher resolution variant of the NAM (below), which is a bit slower, pushes that focus towards dinner time.    Balancing the two out suggests the best chances for thunderstorms will be in the mid afternoon hours, with the focus areas generally along the frontal boundary -- which should lie just to the city's north.

This may provide the season's first severe hail event as well -- the atmosphere has enough dynamics and instability aloft to support larger cumulonimbus clouds (thunderstorms), which can develop hail due to shooting higher into the atmosphere.   Wind is also a threat (as is the case in most severe events).    As the disturbance responsible for this thunderstorm event pulls through Sunday evening, the front may sag south Sunday night and on Monday just enough to cool some places from the city on north for the start of the work week...only briefly though as we'll warm back up for Tuesday.