Updated Sat 8:10 AM highlighted below
Updated Fri 7:30 PM highlighted below

There aren’t too many weekends where I can post the forecast on the preceding Thursday and have high confidence that the forecast won’t change appreciably.

We are locked into a dry, unseasonably warm (hot) pattern from a strong upper level ridge of high pressure.

Friday’s models show a weak upper air disturbance rotating through mid to late afternoon Saturday. Some mid level cloudiness Saturday afternoon. A slight chance of a widely scattered shower 3-5 PM ; most areas dry.

Saturday Update: Any showers on Saturday afternoon will be far northwest suburbs, Pottstown north and west.

While the new GFS model has high temperatures in the upper 80s, many models, including the NBM, have highs of 92° on Saturday and 93° on Sunday! Saving us from the summer-like heat will be dew points only in the upper 50s to around 60°.

We could use some rain (of course, never on the weekend), but none is in sight.

Wind Forecast

 

Updated Sunday forecast Sun 8 AM highlighted below

This weekend’s weather will be marked by an upper air pattern change, where the cool upper air cyclonic flow will transition to a warmer upper air ridge by next week.

Saturday

Prior to the upper ridge taking hold, an upper air low near our area will trigger some instability cloudiness and widely scattered showers Saturday afternoon. Forecasting the exact location of the showers is not possible. The GFS has us dry while the higher resolution “convection allowing” models show some light showers springing up.

Sunny in the morning, instability puffy cumulus partial cloudiness in the afternoon with widely scattered showers possible. There isn’t much “precipitable water”, so any scattered showers will be light. High temp 76.1º sd 1.1º (higher than usual confidence.)

Sunday

A more developed warm front will be lifting through with most of the rain and dynamics far southwest of our area. Some models threaten our western suburbs with showers, but the model blend is keeping the immediate PHL area mostly cloudy and dry.

Despite impressive radar echos in western Pennsylvania Sunday morning, the HREF and NBM models keep the heavy showers and thunderstorms west of the immediate PHL area Sunday.

Some sun in the early morning, then mostly cloudy. A chance of widely scattered showers/thundershowers, mostly far western suburbs. Again, there isn’t much “precipitable water”, although more than Saturday. High 74º sd 2.8º

Winds