Thursday Evening Technical Discussion

Technical Discussion

Synopsis

During Friday and into Saturday, upper level ridging will build over the state. This ridge will bring clearing the skies and more warm and humid conditions. Ahead of the front, warm conditions will continue on Saturday before a slow moving cold front moves through Saturday night into Sunday. This front will bring a chance for showers and thunderstorms. As we move into early next week, an area of high pressure will build into the area with clear, pleasant, fall-like conditions.

Short Term

This evening, an area of low pressure, currently associated with isolated showers and thunderstorms will move out to the east which will give way a ridge of high pressure that will control our weather through Saturday. This high pressure will cause winds to shift to southeast and eventually southwest, bringing in warmer and humid conditions. Both the NAM and GFS MOS indicate dew points creeping up into the upper 60's. I would not be surprised to see some stations in southern PA approach 90 degrees and report dew points near 70 on Saturday as winds from the southwest ahead of the cold front transport this warmer air into the area. With decent moisture around 700 mb levels, there is also a chance for showers and thunderstorms on Saturday afternoon. Both NAM and GFS are very good agreement that the cold front will approach from west Saturday evening into Sunday morning. During the day Sunday, the NAM and GFS both indicate a much better chance for more widespread showers and thunderstorms along the cold front as the atmosphere remains unstable.

 Long Term

Once the cold front clears the eastern part of commonwealth by the evening on Sunday, strong cold air advection will replace the warm and muggy conditions with more autumn-like temperatures. The suite of models are indicating the possibility that the trough could stall over the area on Monday promoting cloudy and cool conditions. With this stalling, showers could remain over the forecast on Monday. However, an area of high pressure will build into the commonwealth mid-week bringing dry, clear and cooler weather.

-Matthew Mehallow