Daily Archives: Sunday, May 31, 2026 9:03 am

Philadelphia Weather Outlook

THIS WEEK’S WEATHER

#Philadelphia #weather #PAwx #PhillyWx

Updated Friday 06/05/26 @ 3:42 AM —The heat is returning for Friday and Saturday with highs 92°-94°. A cold front moves through late Saturday afternoon or early evening. As described in an earlier post, the upper air configuration will work against precipitation developing near Philadelphia and at best we’ll have widely scattered showers and storms

Updated Thursday 06/04/26 @ 9:53 AM — The increasingly dry, warm weather continues as an upper level ridge tries to build in the Central US. Temperatures approaching or exceeding 90º will be likely Friday and Saturday. It appears that we have re-entered a dry pattern.

A ‘cold’ front approaching and moving through on Saturday afternoon and evening will bring an increasing chance of showers and thunderstorms to our area—

00z ECMWF-AI forecast for Saturday evening. A cold front moves through with showers and thunderstorms, especially western sections. The showers may fall apart as they move eastward. (Click on image for larger view.)

Despite what looks like a lot of rain on the above ECMWF-AI graphic, the upper air situation does not support much in the way of rainfall for Philadelphia. As has happened many times in recent months, we will be in what is called the ‘right entrance region’ of a small jet streak—

ECMWF-AI 300 mb winds show Philadelphia in the area of the jet streak called the ‘right entrance region’. The right entrance region has downward vertical motion that is not supportive of rainfall. The showers will likely fall apart as they move through Philadelphia later Saturday afternoon and evening. (Click on image for larger view.)

So the immediate Philadelphia region will likely miss out on another opportunity for much-needed rainfall on Saturday.

Originally Posted Sun 9:03 AM —A relatively stagnant pattern with cold low pressure in eastern Canada and an elongated surface high pressure to our west will keep relatively cool weather and dry conditions for our area this week.

While some of the high resolution models have a disturbance wrapping around this low bringing some widely showers late Monday afternoon/evening, this would likely be the only chance of any precipitation this week.

Tuesday‘s forecast—

06z ECMWF-AI forecast for Tuesday. High pressure combined with low pressure in Eastern Canada will maintain a northerly flow of dry, cool air. (Click on image for a larger view.)

By Thursday, high pressure sinks down into the central US while a semi-tropical system forms in the western Atlantic—

06z ECMWF-AI forecast for Thursday. The somewhat tropical low will move off to the northeast, away from the coast. Dry weather with moderating temperatures for our area. (Click on image for a larger view.)

There’s a chance of more summer-like conditions returning by next weekend, along with the possibility of some rainfall.

During this relatively tranquil weather period of the coming weeks, my posting activity will be reduced from its usual level. The European and Canadian models have made some significant changes to their models in recent weeks with different servers and different parameter names.

The RRFS will be moving to the main NOAA server (called “NOMADS”) from their development location at AWS on June 9th, and over the summer, NOAA will be dropping several long-standing models such as the NAM.

As many long time visitors to this site know, I download and post-process all the model data I use for these forecasts and graphics. I’ve already been working on the updating my data workflows over the past week and I expect the process to continue for the next several weeks. If we get some active weather, I hope to post at that time.