Latest GFS LAMP forecast for PHL has tempertures today (Saturday) only reaching 57 with very windy conditions developing for much of the day.
Philly Weekend Weather Forecast
A strong cold front will move through later Friday afternoon, between 5 and 7 PM.
As posted earlier, the very warm temperatures are NOT predicted to get into Philadelphia before the frontal passage.
Most of the lift dynamics will move to the far north of PHL and most of the instability will be found in southern Delaware, so any thunderstorms in the immediate Philadelphia area shouldn’t be very impressive.
In fact, the NAM has much of the heavy precipitation jumping past PHL and re-developing in southern areas. The GFS still has about 0.5 inches QPF for Philly, the NAM much less.
Update 4PM: The NAM appears to be correct. The precipitation seems to be dissipating as it reaches the PHL area.
High pressure builds in for both Saturday and Sunday. Fair skies and near seasonable temperatures. Highs on Saturday 62 and 67 on Sunday.
Friday Weather Update
All this TV talk about Friday temperatures in the mid 70s for Philly! In actuality, the models keep us cool today, temperatures in the 60s. At no point did the models suggest 70s.
Showers and thunderstorms between 4-8 PM. The NAM has much of the heavier activity south of Philly and into south Jersey and Delaware.