#Philadelphia #weather #PAwx

Friday & Weekend Outlook

Posted Friday 03/28/25 @ 8:38 AM — Over the past several days, there have been significant changes in the model forecasts for this weekend. Here’s a brief summary—

• The warm front will become stationary far north of our area. This area will be the focus of most of the rain for this weekend. Much of the rain will stay to our north. What had looked to be a wet latter half of Sunday, now appears to be much dryer.
• Rain from the system will affect our area on Monday and Monday evening instead of Sunday evening into Monday.

Current water vapor image—

As for today, Friday, most models still have the showers associated with the advancing warm front to pass us to the northwest. The ECMWF-AI, the HRRR and the NAM-NEST keep a forecast of very light showers Friday evening, anytime between 6 PM and midnight.

I’ll post my regular “Weekend Weather Forecast” late this afternoon with an update.

Thursday and Friday Outlook

Posted Thursday 03/27/25 @ 10:04 AM — I’m finally hearing the words “near 80 degrees” for Saturday in the TV/Radio forecasts. The ECMWF-AI model has been predicting these temperatures since Tuesday.

For today, Thursday, it will be sunny and continued windy and somewhat chilly.

To get to 80 degrees, a warm front will need to pass through our area Friday night.

Earlier this week, the models only showed showers to our far northwest with this warm frontal passage. The latest models are showing some showers breaking out as early as Friday afternoon ahead of the front.

Here’s the latest HRRR which is forecasting showers and thunderstorms as early as 4 PM Friday afternoon—

Thursday and Weekend Outlook

Posted Wednesday 03/26/25 @ 5:15 PM — Showers formed, mostly to the north of the Philadelphia area today, and radar showed precipitaton over Philadelphia which evaporated before making to the ground. Significant shower activity broke out at the Jersey Shore this afternoon from the upper air disturbances discussed in this morning’s update.

Thursday is still showing cooler temperatures,(53º-55º) but plenty of sunshine. Still somewhat windy and gusty.

A warm front moves through Friday night and the ECMWF-AI-Single and Canadian RGEM models are still showing 80º+ for our area on Saturday.

Rainy weather moves in late Sunday afternoon and continues through Monday. the Phillies opener may be affected.

Wednesday Forecast Update

Posted Wednesday 03/26/25 @ 9:48 AM — Several models (ECMWF, Canadian RGEM, German ICON) are showing some fast moving instability showers moving through here early afternoon. There will be some sunshine in the [late] afternoon, according to the HRRR, but not as much as forecast yesterday. So clouds and some sprinkles is a better bet for late morning and early afternoon.

Current Water Vapor shows showers likely to pass to our north, but positive upward motion just to our west may produce showers here between noon and 1 PM and in NJ—

Wednesday through Saturday

Posted Tuesday 03/25/25 @ 6:04 PM — The fast moving low pressure system expected to form this evening will remain to our south. Rain may extend north into South Jersey, but the Philadelphia area will remain dry. Colder weather for Wednesday and Thursday with high temperatures around 50º with sunny skies. A warm up Friday. A big surprise for Saturday- high temperatures may approach 80º!

A rainy period develops Sunday into next Monday.

Winds Return for Tuesday

Posted Monday 03/24/25 @ 5:50 PM — Windy conditions, especially Tuesday morning, with gusts 25-30 mph. Highs return to about 57º-58º after a cold morning. Some clouds move in late afternoon.

Mon 5:47 PM —Forecast Review — The rain ended about 4 PM and some sun is breaking out as I write this. Total rainfall, was somewhat higher than forecast in areas east of the city.

Posted Monday 03/24/25 @ 8:58 AM — Based on radar and the latest HRRR, the rain will be ending about 2 PM-3 PM around Philadelphia and about 5 PM to 6 PM at the Jersey Shore. (The Canadian RGEM has the rain ending about 3-4 PM here with some sun possibly by 6 PM. )

As for that potential ‘experiment’ with the ECMWF-AI model, its forecast for some rain here is now late Tuesday night, with light rain ending for the daytime Wednesday. The GFS has moved closer to the ECMWF-AI with some rain in NJ late Tuesday night.

Originally Posted Sun @ 4:25 PM — —Low pressure and an associated cold front will move through on Monday. Rainfall looks to be in the 0.45″ range, but several models have as much as 0.75″ of rain falling over our area. Rain starts before daybreak Monday and continues through at least 4 PM, when any remaining precipitation will become light and widely scattered.

Overall, this coming week looks to be colder than recent weeks with a persistent dip in the jet stream over the Central and Northeastern US.

The current satellite water vapor image with superimposed RAP model parameters and MRMS radar shows the setup that will be persistent—

Of interest is the energy in the Pacific Northwest diving southward into the upper trough. The latest ECMWF-AI model shows another storm developing Wednesday which lends itself to another “AI model Experiment“.

Basically this AI model shows much more development of this Wednesday low pressure system than the either the GFS or ECMWF—

Yet another system associated with a warm front approaches Friday or Saturday. Temperatures look to moderate by next weekend.

#Philadelphia #weather #PAwx

Fri 9:24 AM —Forecast Review — Last evening’s rain arrived within the time range given, but really about an hour or so later than I had expected. Total rainfall was somewhat on target, with much heavier rain than forecast eastern areas and in New Jersey.

Here’s the MRMS QPE (quantity of precipitation estimate)

Thursday Forecast Update

Posted Thursday 03/20/25 @ 11:04 AM — It looks like the breaks of sun will be in the morning. Increasingly cloudy in the afternoon.

Posted Thursday 03/20/25 @ 8:42 AM —Today’s forecast mostly on-track. Low clouds this morning will give way to mid level cloudiness this afternoon. Some areas may see some sun for a period this afternoon, but most will remain cloudy. Showers and rain moves in from the west between 5:30 PM and 8 PM. Total rainfall this evening between 0.45″ and 0.70″ (western suburbs may receive the higher amount). Windy conditions later this afternoon and then again later tonight. The actual frontal passage may not have much in the way of winds.

Posted Wednesday 03/19/25 @ 5:57 PM — The AI ‘experiment’ showed no winners, with the spatial and temporal resolution differences between the models over-shadowing any small differences in forecast high temperatures. That said, except for Center City, the NBM high temps were overall too low. Here’s the RTMA temps at 3:45 PM. the likely high temps for the day—

As for Thursday, a cold front (technically an ‘anafront’ type cold front, due to the rain following the frontal passage) will move across about 6 PM with showers and possible thunderstorms.

Low clouds in the morning with mid-level cloudiness in the afternoon. Some breaks in the overcast possible just before the front moves across about 6 PM. Low pressure expected to form along the anafront, bringing more windy conditions. About 0.4-0.6″ of rain expected during the evening Thursday.

Yet Another AI Model ‘Experiment’

Posted Wednesday 03/19/25 @ 9:34 AM — There are differences today between the high resolution NBM model (our best model for temperatures) and the lower resolution ECMWF-AI-Single model regarding high temperatures for today.

The AI model has an easterly wind keeping temperatures from the city eastward below 70º, while large areas just west of the city are above 70º

Here’s the latest 12z NBM model high temperature forecast for today—

An interesting and significant difference in the forecast. Either way, a very nice day, with some high thing cirrus clouds moving in about 3 PM.

Thursday will likely have rain moving in between 3PM and 6 PM ahead of a cold front. Some ‘interesting’ weather possible.

Wednesday through Thursday Outlook

Posted Tuesday 03/18/25 @ 5:34 PM — Wednesday promises to be a spectacular day, with mild temperatures just short of 70º. Sunshine in the afternoon will be through some thin cirrus clouds as moisture and milder air move in aloft ahead of a cold front expected late Thursday.

A strong cold front approaches on Thursday with some rain/showers moving in by mid to late afternoon—

About 0.5″ of rain is expected with this system.

Originally Posted Mon 8:04 AM —Some rain is still falling at the Jersey Shore and there’s a chance of a light shower this morning, especially east into NJ.

Clouds should break for some sun around noon or early afternoon.

The rain occurred later than forecast, the strong wind gusts preceded the rain. Many areas did eventually receive the 1+ inch forecast —

Our next chance for rain is late Thursday into Thursday night with a system somewhat similar to Sunday’s cold front passage.