Daily Archives: Friday, April 3, 2026 11:19 am

Philadelphia Area Weather Forecasts

WEEKEND WEATHER FORECAST

#Philadelphia #weather #PAwx #PhillyWx

Sunday Forecast Update

Posted Sunday 04/05/26 @ 8:56 AM — I’ve been having fun working with Anthropic’s Claude AI to create specialized derived data from the RRFS model data input. As an experiment today, the “500mb Dynamic Forcing” shows some reasonably hefty triggers (orange below) for strong storms in the white box below.

10z RRFS shows two areas of significant “forcing”-(orange) dynamics that trigger strong upward motion. The strong storms occur northeast of the maxima (orange) along the 500mb wind streams. Just an experiment. (Click on image for a larger view.)

Posted Sunday 04/05/26 @ 8:22 AM — The cold front is just to our west and the models continue to forecast about a 4 hour period of rain, beginning about 11:30 -noon (Blue Bell) and about an hour earlier in western Montco/Bucks/Chester counties.

Current satellite water vapor image (8 AM) with superimposed RAP model 500-1000 mb thickness lines (yellow), Mean Sea Level Pressure isobars (black contours) potential vorticity (fine violet contours) with superimposed MRMS RADAR. Water Vapor Imagery reveals emitted water vapor infrared TEMPERATURE, NOT REFLECTED LIGHT from CLOUDS. (Click on image for a larger view.)

Looking at the latest models, I don’t see any severe weather for our area today, but the front may pick up some energy by the time it reaches the Jersey shore later in the afternoon.

Sun 8:19 AM —Forecast Review — The warm front was supposed to be north of our area last night, but it became a backdoor cold front as high pressure pushed it south and a cooler easterly flow was with us, causing the early morning fog. The warm front is finally moving north of our area again as I write this and winds are shifting to the southwest ahead of the approaching strong cold front.
Saturday Forecast Update

Posted Saturday 04/04/26 @ 8:36 AM — A weak ‘cold’ front (wind shift) moved through over night and winds have shifted to the north.

Current satellite water vapor image with superimposed RAP model 500-1000 mb thickness lines (yellow), Mean Sea Level Pressure isobars (black contours) potential vorticity (fine violet contours) with superimposed MRMS RADAR.
(Click on image for a larger view.)

The weak boundary will return as a weak warm front again this afternoon and evening. Some scattered showers, perhaps some thundershowers will break out about 3-7 PM, mostly south and then west of the city. Exact placement not possible. The front will continue to move north over night with additional scattered showers .

4 PM Saturday—

06z RRFS with drawn warm front position at 4 PM (Click on image for a larger view.)

As a result, high temperatures will be pleasant and closer to 78-79º instead of the 80s previously forecast.

No change in Sunday’s forecast at this time.

Weekend Forecast

Posted Friday 04/03/26 @ 4:59 PM — With the warm front having moved north of our area, weak high pressure will be in control for Saturday. A cold front moves through about 2 PM on Sunday.

Saturday Forecast

Fog around daybreak, then becoming sunny. While high pressure will be in control, some upper level weak disturbances may set off some light scattered showers between 3 PM and 5 PM on Saturday. Mostly sunny but some clouds at times.

High Temperatures Blue Bell, 81º Philadelphia 83º Above average uncertainty with a sd of ± 3.3º

Sunday Forecast

Some sunshine early, the cloudy by 10 AM. It will be windy. Showers and possibly some thunderstorms move through between noon and 3 PM. I don’t see much in the way of severe weather.

18z RRFS 1 hour accumulated rain at 1 PM Sunday. (Click on image for a larger view.)

Temperatures peak in the morning and fall during the afternoon and evening. Highs 71 Blue Bell, 73º Philadelphia Above average uncertainty of ± 3.3º

Weekend Preview

Posted Friday 04/03/26 @ 4:56 PM — High temperatures were in the upper 60s on Friday, closer to the ECMWF-AI forecast and quite a bit lower than the forecast by the new NBM.

Originally Posted Fri 11:19 AM —The warm front will move north of us today. There should be clearing about 1 PM southwest and west of the city, and between 2-3 PM in Philadelphia.

Current warm front position at 10:15 AM—

Approximate Warm Front Position at 10:15 AM Friday. Despite my attempt to draw the position, warm fronts are not as distinct as cold fronts. (Click on image for a larger view.)

It should be noted that the NBM has highs near 79º by late afternoon, while the ECMWF-AI has the warm front passage slower and keeps us only in the upper 60s. to near 70 in South Jersey. The latest RRFS confirms this, with highs just reaching 70 into KPHL airport.

Saturday should be sunny and warm., Highs upper 70s to low 80s.

Sunday rain begins in the morning and continues into the afternoon. More about this later today.