Philadelphia Area Weather Forecasts

THIS WEEK’S WEATHER

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Cancel That Snow

Posted Friday 02/13/26 @ 9:15 AM — Last night’s models have moved in the direction of the GFS, with the Sunday storm mostly staying to our south. (The European models are often depicted as the Mercedes-Benz of models and the GFS as a Chevy. This is a good example of where the GFS appears to be the more accurate model. Not the first time this season!)

The several inches predicted by yesterday’s ECMWF-AI now appears to be dusting or a coating of snow at most. Most of the precipitation will fall as light rain or a wet mix of sleet and rain. Surface temperatures will be above freezing for most of the precipitation.

06z ECMWF-AI total snow accumulation through early Monday morning. (Click on image for a larger view.)

Still some uncertainty with this forecast.

High Uncertainty with Sunday’s Forecast

Posted Thursday 02/12/26 @ 8:41 PM — Additional model runs this evening have backed off on the heavier snow forecast by this afternoon’s ECMWF-AI. The latest ECMWF-AI (18z) has reduced the amount by about half, while the GFS, ECMWF show an inch or less. An interesting forecast with low confidence and high uncertainty at this time horizon.

Forecast Change Now Showing Snow Possible

Posted Thursday 02/12/26 @ 5:19 PM — The models have continued with an evolution of the forecast change that began a few days ago. Today’s models are showing a northward trend in the precipitation shield with a storm passing to our south on Sunday.

Additionally, the precipitation arrives later in the day, with temperatures falling below 32º. Combined with temperatures at critical levels in the atmosphere below freezing, snow is now forecast by the latest ECMWF-AI model.

The latest available ECMWF shows the precipitation shield northward. Note that Philadelphia and surrounding areas are north of the red, magenta and yellow “critical thickness lines”, indicating the vertical temperatures are cold enough for snow—

12z ECMWF model forecast for 7 PM Sunday. Note the position of the red, magenta and yellow thickness lines are south of our area, indicating snow. (Click on image for a larger view.)

The latest ECMWF-AI model shows significant snow accumulations for our area—

12z ECMWF-AI Snow forecast by late Sunday night. (Click on image for a larger view.)

There are major differences in the model forecasts, so it’s too soon to take either model forecast literally.

The latest AI-GFS has a very different forecast, with only a trace of snow here by Monday morning—

18z AIGFS forecast has virtually no snow here. (Click on image for a larger view.)

This storm forecast has changed significantly over the past two or three days. The current forecast is likely to change again in either direction.

Stay tuned for updates

Forecast Change?

Posted Thursday 02/12/26 @ 8:21 AM — My last update from Tuesday posted— “I don’t see any precipitation here for at least a week.” At that time, all models had another disturbance moving to our south, not reaching us. However, over the last day, several (but not all models) show this southern storm having its precipitation shield (rain or mostly rain) just reaching our area on Sunday.

The ECMWF-AI model captures this well—

00z ECMWF-AI forecast for Sunday. Precipitation Shield just reaches the Delaware Valley (Click on image for a larger view.)

The AIGFS still keeps the rain to our south. Will update later today.

Forecast Update

Updated Tuesday 02/10/26 @ 9:55 PM — Areas of precipitation will pass to our north and to our south. There could be a some very light precipitation towards morning but most areas will remain dry.

18z ECMWF-AI forecast for Wednesday. Upper low to our north and a surface low to our south will merge far off the coast. Windy conditions are expected. (Click on image for larger view.)

Another area of precipitation will also pass to our south around the Monday time frame. I don’t see any precipitation here for at least a week.

Somewhat Milder

Updated Monday 02/09/26 @ 9:16 PM — There’s been little change in the forecast since my last update. Temperatures will approach or exceed 40º by Wednesday. Windy conditions will also develop Wednesday as low pressure scoots to our south.

18z NBM forecast temperatures for Tuesday through Thursday. The top line shows the forecast highs (about 40 on Wednesday) for the day with a standard deviation of ± 2º. As you can see ,high temperatures fall again on Thursday. (Click on image for larger view.)

There’s a strong signal from the AI models that a significant warming trend will develop around February 16th and afterwards with a large scale upper ridge influencing our weather.

Originally Posted Mon 8:39 AM —This week, as high pressure moves to our east, the jet stream will flatten and the extremely cold air over our area for so long will moderate somewhat with temperatures approaching 41º by Wednesday. (Still below seasonal average of near 44º.)

12z ECMWF-AI. Winds at 300mb height (jet stream). Flat zonal flow through our area will inhibit development of low pressure, but with some changes in configuration, may act as a conduit for moisture and low pressure next weekend. (Click on image for larger view.)

Another slight dip in the jet flow will usher in some colder air again on Friday and Saturday. An approaching large system may bring a mix of rain and some frozen precipitation, but the odds favor wet vs white.