Category Archives: Philadelphia Area Weather Forecasts

Philadelphia Area Weather Forecasts

WEEKEND WEATHER FORECAST

#Philadelphia #weather #PAwx #drought

Posted Saturday 10/26/24 @ 4:45 PM — Still keeping an eye on the potential for some rain here in Philadelphia, but we’ll have to wait until November 3rd though November 6th, according to the statistical ensemble models and the GFS, ECMWF AI models.

The latest GFS Graphcast Machine Learning-AI model is the most aggressive with some rain and low pressure development—

GFS-GRAPHCAST AI model forecast for Monday Nov 6th.

The latest ECMWF-AIFS is less aggressive with low pressure development and rainfall here—

ECMWF-AIFS forecast for Monday November 4th. Of interest is possible tropical development near Cuba. Some of the ensemble models show moisture from this tropical development moving up the coast towards us. (Click on image for a larger view.)
An interesting article in today’s Washington Post on AI weather models —

“AI is transforming weather forecasting. Is the U.S. falling behind?“

Originally Posted Fri @ 5:41 PM — —Our dry sunny weather continues…

A cold front will make a dry passage through the area tonight. It will take some time for the cold air to filter in, so Saturday will be in the mid 60s and temperatures drop into the mid to upper 30s Saturday night.

Sunny skies will continue Sunday with highs dropping to the upper 50s to near 60º in some spots. Cold temperatures Sunday night before things warm up again into next week. Indeed, we may see temperatures near 80º on Halloween!

With so little happening weather-wise in the short term, I’ve been checking the extended range models and newer AI models for any signs of some rain here, Our next chance of any rainfall appears to be between November 2nd and November 5th. Some of the extended statistical ensemble models hint at some unsettled weather during this period and perhaps a pattern change.

Here’s the latest ECMWF-AIFS forecast for Sunday, November 3rd—

10-25-24 12z ECMWF-AIFS forecast for Sunday November 3. A cold front moves through. Much of the heavier showers stay to our northwest, but there are signs that low pressure may form along the front, giving us more rainfall during the following days. (Click on image for a larger view.)
Philadelphia Area Weather Forecasts

WEEKEND WEATHER FORECAST

#Philadelphia #weather #PAwx

There’s almost no reason for a weather forecast for this weekend and certainly not a reason for many updates. You’ve heard the details on the radio or TV.

Sprawling dominant high pressure and a persistent upper air ridge will give us sunny skies and increasingly warm temperatures. I don’t see any rain here in the Philadelphia area until the end of October, possibly on Halloween, according to the NAEFS and into November according to the GFS AI model.

During this downtime, I’ve been exploring programming downloads and post processing of some the the experimental AI models.

Regular readers here have seen that the ECMWF-AIFS was quite impressive with its forecast of Helene and Milton.

NOAA also has what they call an experimental “machine learning model” which is a combined effort with Google (Graphcast) and uses the weather database of the ECMWF. It compares current conditions to a weather database going back to the late 70s with several parameters at 13 vertical atmospheric levels to create a forecast.

Over the past week or so, I’ve been working on programming the download and post processing of what’s called the Experimental Graphcast-GFS model. (Weather model downloads are much more complex than simply “click here” for the model.)

Here’s its forecast for October 31st at 8 AM, showing the first area of rain on the map for awhile. Notice that the rain is blocked to our west by high pressure.

10-18-24 00z Experimental Graphcast GFS for Halloween morning. High pressure still blocking rainfall. But it suggests a pattern change within several days of this date. (Click on image for a larger view.)