Daily Archives: Friday, January 2, 2026 5:51 pm

Philadelphia Area Weather Forecasts

WEEKEND WEATHER FORECAST

#Philadelphia #weather #PAwx #PhillyWx

Sunday Update & Pattern Change??

Posted Sunday 01/04/26 @ 9:30 AM — Today’s Eagles will have clear skies and temperatures near 36º at the game start and around 30º when they win. Winds will be in the 6-11 mph range.

The warm up this week continues to be forecast by all the models with temperatures reaching 60º+ on Saturday. (Friday’s rain will keep temperatures in the 40s according to the ECMWF-AI or low 50s according to the NBM, not as high as previously forecast.)

As described last week, I think this warm up qualifies more as a passing “weather change” than a “pattern change”. Why? The same cold pattern returns by next Sunday! The following forecasts from the new hybrid AI HGEF and the NAEFS demonstrate the point—

Today, Sunday, as captured by the HGEFS—

Today’s (Sunday) HGEFS forecast. Notice the position of the jet flow (blue lines) along with the trough and ridge. We’ve been in a persistent trough “pattern” for quite some time. (Click on image for a larger view.)

By next Friday, we transition temporarily into upper ridge rather than a trough—

HGEFS forecast for Friday. Notice we’re now in a warmer ridge. But not for long! (Click on image for a larger view.)

By late next Sunday, we’re back into the same trough “pattern” we’ve been in through much of this past Fall and through December—

NAEFS forecast for next next Sunday. We’re back where we started with an upper level trough over the eastern half of the US. (Click on image for a larger view.)

Calling our brief warm up a ‘pattern change’ is presumptuous. The term “pattern change” should be reserved for when a jet flow pattern truly becomes persistent.

Originally Posted Fri 5:51 PM —Cold weather continues through the weekend as high pressure from Canada will continue to build in. The cold high pressure system will block precipitation in the south from reaching us.

12z NAEFS forecast for late Saturday afternoon. (Click on image for a larger view.)

Saturday Forecast

While the system moving to our south will not bring us any snow or rain, moisture aloft will result considerable cloudiness to cloudy for much of the day. Winds lighter but still noticalble.

NBM high temperatures: Blue Bell, PA 31º Philadelphia, PA 33º
Low uncertainty (based on standard deviation): ±1.2º

Sunday Forecast

Mostly sunny in the morning. Partly cloudy in the afternoon. Somewhat windy and gusty again in the afternoon. Cloudy towards sunset.

NBM high temperatures: Blue Bell, PA 35º Philadelphia, PA 38º
Lower Than Average Uncertainty (based on standard deviation): ± 1.0º

Friday’s Forecast Review talked of a ‘pattern change’, but looking at the long range forecast out to 300 hours, the warm up we’ll be seeing next Wednesday through next Friday will be more of ‘weather change’ than a ‘pattern change’. While it may last a few days into next weekend, the longer range looks quite changeable with alternating periods of colder and milder. I like to reserve the phrase ‘pattern change’ as something that becomes persistent over weeks.