Update

The GFS forecast appears to be on-track for today.   It will be raining for the entire day, with heaviest rain late afternoon (4 PM) into the early evening.

Some uncertainty about Sunday’s cloud cover.   The cyclonic flow will result in some degree of cloudiness with sunshine.  The NAM suggests the possibility of a brief shower Sunday afternoon due to instability.

Philly Weekend Weather Forecast

The forecast remains essentially unchanged.  Low pressure and an easterly flow will bring rain for much of Saturday.  Rain will begin by mid to late Saturday morning  and become heavier into the afternoon and evening. There’s a chance of embedded thunderstorms late afternoon.  Windy with temperatures near 70.  The latest models have backed away from the multiple inches of rain here, but locally heavy rain with convective thunderstorms is possible.

For Sunday, the rain ends before daybreak , but a cyclonic flow will keep the skies from fully clearing.  So a mix of sun and clouds with temperatures near 80.

Philly Weekend Weather Outlook

GFS forecast for early Saturday evening
GFS forecast for early Saturday evening

The models have been consistent in predicting low pressure development along a stalled frontal boundary, with heavy rain for Saturday in our area.

The models have the precipitation lifting out to the northeast on Sunday, but the amount of clearing is uncertain, since we will still be in a cyclonic wind flow.

 

Weather… and other things "up in the air"