Daily Archives: Monday, September 7, 2026 10:09 am

Philadelphia Area Weather Forecasts

THIS WEEK’S WEATHER

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Friday and the Weekend Outlook

Posted Thursday 09/10/26 @ 5:26 PM —A disturbance will pass to our south along the stalled front that went through here this morning. The rain will stay to our south.

18z RRFS forecast- total rainfall Thursday night through 1PM Friday (Click on image for a larger view.)

Cloudiness in the morning Friday will dissipate for sunshine by around noon or 1 PM.

The stationary front to our south will return as a warm front over the weekend. Saturday may start sunny but increasing cloudiness will occur after noontime. Rain moves in either late Saturday afternoon or if we’re lucky, later in the evening.

Rain Saturday night will continue Sunday morning before ending by late morning early afternoon.

Skies should at least partially clear Sunday afternoon. Total rainfall about 0.70 inches, possibly up to 1.0″ in some areas is expected at the current time, although the RRFS is showing 1-2 inches.

The timing of this rainfall will determine how much impact it has on this weekend.

Wednesday-Thursday

Posted Wednesday 09/09/26 @ 9:50 AM — The edge of the heat dome is expected to move to our north today. Current water vapor image with RAP model shows the set up—

Water Vapor image at 9:45AM with superimposed RAP model Mean Seal Level pressure (black contours), 500-1000mb Thickness (yellow contours), RAP potential vorticity contours (violet fine contours) with MRMS Radar. The edge of the dome is approximated by the 576 thickness contours (yellow). Colder high pressure from Canada is trying to push a cold front through later Thursday. (Click on image for a larger view.)

The models have been very inconsistent with the forecast for the next 5-7 days and there’s been a lack of consensus regarding the amount and timing of the rain associated with the cold front Thursday afternoon/evening and whether the cold air will suppress the heat to our south or whether it will quickly return as a warm front.

There’s also some question about where the front stalls to our south and whether a wave of low pressure will ride along it, bringing some rain for some part of the weekend.

I skipped updating this blog yesterday because I saw no clarity. (Even the AI models differed with each other and their own regular deterministic models.)

Here’s the current forecast trend. I expect changes will be necessary.

Today– Sunny and increasingly warm and humid.
Thursday– Some light showers in the morning, partial clearing in the afternoon. Warm and humid.
Friday– Some showers in the morning as low pressure moves along the stalled front to our south. Still mild.
Saturday– Increasing cloudiness. Some showers move in in the afternoon and evening.
Sunday– Showers in the morning, some clearing in the afternoon. Cooler.

Regarding any showers, rainfall from the city and northward is expected to be very minimal. The showers associated with the cold front Thursday have been consistently forecast to weaken considerably in our area.

Tuesday-Wednesday-Thursday

Posted Monday 09/07/26 @ 8:04 PM — A few weather map graphics summarize the next three days.

Tuesday—

18z GFS forecast for 2 PM Tuesday. Sunshine through high thin cirrus clouds only (tan) (Click on image for a larger view.)

Wednesday—

18z GFS forecast for 11 PM Wednesday. Southwesterly winds and the edge of the heat dome (576 thickness line) is now over Philadelphia. Wednesday will feature sunny skies, with much warmer temperatures and higher humidity, especially by late in the day. (Click on image for a larger view.)

For Thursday, a cold front drops south over us with clouds and showers. There are large differences between the ECMWF and the GFS. The ECMWF has showers moving in early afternoon. The GFS has only clouds in the morning and afternoon with showers/thunderstorms at night.

12z ECMWF forecast for Thursday at 2 PM. Showers just entering Philadelphia. The GFS (not shown) has just clouds at this time of day. (Click on image for a larger view.)

Originally Posted Mon 10:09 AM — Continued fair weather is expected through Wednesday. The edge of the heat dome that been pushed southwestward over the weekend will slowly advance back north towards us by Thursday.

Water Vapor image at XX with superimposed RAP model Mean Seal Level pressure (black contours), 500-1000mb Thickness (yellow contours), RAP potential vorticity contours (violet fine contours) with MRMS Radar with surface wind barbs, The edge of the heat dome is approximated by the 576 thickness line. (Click on image for a larger view.)

A cold front is expected to move through sometime Thursday afternoon into the evening accompanied by rain and thunderstorms.

A nice weekend is looking likely with a return to very warm (hot) conditions by next Monday.

Temperatures / Dew points expected this week

12z Model Blend Meteogram for Blue Bell, PA (Click on image for a larger view.)