Philadelphia Area Weather Forecasts

WEEKEND WEATHER FORECAST

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Sunday and Week’s Hi Temp Outlook

Posted Sunday 06/28/26 @ 9:09 AM — Several models have returned to a forecast of some showers/thundershowers northwest of the city and entering over to NJ. Here’s the latest REFS model snapshot for 6 PM and total rainfall, indicating its eastern extent of the forecast showers—

Rainfall at 6 PM
Total Rainfall

Severe Heat Thursday – Friday

I’ve been forecasting the weather a very long time. I’ve never seen forecast high temperatures as extreme for our area as what’s being forecast for end of this week. Here’s the latest ECMWF forecast highs about 5 PM Thursday—

00z ECMWF forecast high Temperatures about 5 PM Thursday (Click on image for a larger view.)

Here’s the Model Blend Mean Temp forecast for Thursday—

12z NBM just available. Mean High temperatures for Thursday. Note that the standard deviatioin is ±3º Per the ECMWF, these temps could be 3º hotter! (Click on image for a larger view.)

I’ll be dusting off the Wet Bulb Globe Temperatures and the Heat Index (Apparent Temperatures) this week.

Sunday Forecast Update

Posted Saturday 06/27/26 @ 8:17 PM — Sunday will begin cloudy, but clouds will thin towards noontime and most of the day will be sunny through varying amounts of mid and high clouds. Some models do show intermittent periods of low clouds in the afternoon. A northeasterly wind will keep temperatures in the low to mid 80s, but dew points will be in the noticeable upper 60s.

Today’s models are still showing widely scattered storms Sunday afternoon and early evening, but they will mostly stay north and west of Philadelphia.

Outlook-
Things become increasingly hot by Tuesday. By Wednesday, we’re approaching 100º. Thursday looks to be in the low 100’s!

19z NBM (model blend) highs at 2 PM. Actual high temperatures occur between 3-5 PM so these numbers are likely too low! (Click on image for a larger view.)
Forecast Update

Updated Friday 06/26/26 @ 10:41 PM — Tonight’s early models are showing more scattered popup thunderstorms/showers on Sunday than previously forecast. Details on an update tomorrow.

Originally Posted Fri 7:46 PM — As discussed earlier Friday, there had been a trend for the showers and rain to be mostly south of the Philadelphia area but today’s latest models no longer show that trend.

Low pressure moving along a somewhat stationary/warm front will bring showers and thunderstorms Saturday.

Current (4:41PM) 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.)
Saturday

Low pressure moving along the front will bring periods of showers, maybe a thunderstorm from early morning to late afternoon. Highs (Model Blend): Blue Bell- 78º Philadelphia 81º ±4.5º (Higher than usual uncertainty.)

Sunday

Mostly sunny through thin high cirrus clouds. An occasional period of cloudiness. Highs (Model Blend): Blue Bell- 83 º Philadelphia 86º ±4.0º Higher than usual sd and uncertainty.

Some scattered thunderstorm activity possible Sunday evening.