Daily Archives: Friday, August 25, 2023 5:14 pm

Philadelphia Area Weather Forecasts

WEEKEND WEATHER FORECAST

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Update

Updated Sun 08/27 @ 7:41 PM —It didn’t look like it would happen, but some showers have been popping up, just as several models had predicted earlier this morning, occurring a just a bit later later than forecast.

MRMS radar image at 7:35 PM. Showers are expected to slowly drift around and will dissipate later tonight. Many areas won’t see a drop of rain. (Click on image for a larger view.)
MRMS radar at 7:57 PM (Click on image for a larger view.)

Sun 10:05 AM Forecast Review — There were plenty of clouds on Saturday, the result of the short wave that moved through, affecting South Jersey with some showers.

Did anyone hear the TV or radio weather people talk about the cloudiness that occurred?

Radar at 3 PM Saturday showed some localized showers in South Jersey. The wind convergence line is visible on radar as well. Not as much activity as predicted by the HRDPS, but still reasonably accurate.

Today, Sunday, the HRDPS is predicting a similar shortwave to move through, this time affecting areas closer to Philadelphia. Will it happen?

HRDPS forecast for today, Sunday, at 6:30 PM. A period of clouds and some showers. Will it happen?

Saturday Forecast Update

Updated Sat 08/26 @ 9:23 AM — Sunshine is expected by late morning. The HRDPS has been consistently predicting a mid level wave to form during the afternoon over South Jersey. Combined with low level wind convergence and high dew points, showers and some thunderstorms are expected to form between 2 PM and 6 PM this afternoon in South Jersey.

Todays’ 06z HRDPZS shows showers and thunderstorms in South Jersey this afternoon. (Click on image for a larger view.)

The NCEP models weren’t emphatic about this possibility, but the latest HRRR suggests the same.

Update

Update Fri 8/25 10:55 PM — A review of tonight’s models still suggests that Sunday will have a period of cloudiness and even some light sprinkles during the mid to late afternoon, mostly southern areas. Still a low confidence forecast regarding this possibility..

Previously Posted Fri 5:14 PM —


A cold front will move through Friday night into early Saturday. A few widely scattered showers possible tonight, but most areas will be dry. High pressure will build in for much of Saturday. A secondary cold front moves through Saturday evening.

The current water vapor image shows the weak low with the secondary cold front and the possible area of low pressure development on Sunday—

Water Vapor image with superimposed RAP model jet windstreams (white)_and 500-1000 mb contours (orange) Secondary Cold Front (blue). Disturbances will track south of us over the weekend, with some uncertainty for Sunday in southern areas of Chester County and Delaware/ South Jersey. (Click on image for a larger view.)

For Sunday, there’s been a question about low pressure developing along the coast to our south, possibly with clouds and light showers for southern areas, especially South Jersey. Latest models have begun to downplay this possibility.

Saturday

Cloudy in the morning, becoming sunny by afternoon. Very warm and still somewhat humid. Breezy.

High temperature 86º ( NBM model— location Blue Bell, PA)
High temperature 89º ( NBM model— location Philadelphia, PA)

Sunday

Sunny with periods of considerable cloudiness. (There’s lower then average confidence in cloud cover forecast at this time.) More cloudiness likely in areas of southern Chester and Delaware counties as well as southern NJ.

High temperature 81º ( NBM model— location Blue Bell, PA)
High temperature 84º ( NBM model— location Philadelphia, PA)

Winds
18z NBM model wind Meteogram for Blue Bell, PA. (Click on image for a larger view.)