Daily Archives: Sunday, November 17, 2024 6:19 pm

Philadelphia Weather Outlook

THIS WEEK’S WEATHER

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#Philadelphia #weather #PAwx #Drought

A weak cold front will move through around daybreak Monday morning. Some models are showing a few widely scattered sprinkles in early morning hours; other models show weak radar echoes where rainfall never reaches the ground.

Monday should become sunny and windy.

Tuesday will be sunny in the morning with increasing cloudiness in the mid to late afternoon.

Wednesday will be mostly cloudy. An increasing number of models are showing some showers, especially south of the city, in the morning with more heavier rain moving during the early evening.

There’s a continuing signal for moderate to heavy rain as low pressure forms near us on late Wednesday into Thursday. While some models have the heaviest rain north of us, most are forecasting at least 0.6 to 1.0″ which would be the heaviest rainfall we’ve had here in months.

It looks like it might be quite stormy late Wednesday through Thursday as very windy conditions develop.

Here’s the latest ECMWF-AIFS and the Graphcast-GFS AI model forecasts for Thursday morning—

11-17-24 12z ECMWF-AIFS AI model forecast for 7 AM Thursday. The red contour is the 500-1000mb thickness line, which in winter is a rough dividing line between rain and snow. Notice the deep level low over the Great Lakes. (Click on image for a larger view.)
11-17-24 06z Graphcast-GFS AI model forecast for 7 AM Thursday. The red contour is the 500-1000mb thickness line, which in winter is a rough dividing line between rain and snow. Note that the Graphcast-GFS AI model is released over 14 hours after the model is run, quite a lag. It’s difficult to compare the ECMWF and GFS AI models in real time due to the lag. (Click on image for a larger view.)

Friday looks to be unsettled with clouds and sun, windy and cold and possibly some light scattered showers. Snow flurries are possible far north and west of Allentown.

My regular visitors to this site probably have noticed that I’m increasingly using the AI models for this site. I’m really fascinated to see if they do as well (or better) than traditional numeric weather prediction models. This storm will be a good test, as they are predicting heavier rainfall for us than the traditional models.