Philadelphia Area Weather Forecasts

THIS WEEK’S WEATHER

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Friday Forecast Update- A New Wrinkle

Posted Friday 12/05/25 @ 9:05 AM — Current Radar and Water Vapor imagery shows the snow falling to our south. Unless there is strengthening of the southern system expanding it northward, it looks unlikely that the precipitation shield will over-spread the area as forecast by last night’s REFS. Yesterday’s NBM forecast looks to be the ‘winner’. Flurries, at most, can be expected near the city.

Current Radar Water Vapor—

This morning’s Water Vapor with superimposed KDIX radar and MRMS radar. RAP model 700 mb winds and Omega shown. Green Arrows— Upstream from us, there is no precipitation failing. (Click on image for a larger view.)

Here’s the latest 12z NBM, just available—

Today’s 12z NBM Total Snow accumulation; It shows no snow accumulation even close to Philadelphia. (Click on image for a larger view.)

We’ll stay with the NBM with this system. As the storm moves off the coast, some moisture and warm air will be thrown back into our area. Some freezing rain/drizzle is expected after midnight.

12z NBM shows light drizzle and freezing rain and a mix moving in from the southeast after midnight. (Click on image for a larger view.)

I’ll update later this afternoon with this new wrinkle in the forecast.

Friday’s “Minimal Snow” Update

Posted Thursday 12/04/25 @ 7:24 PM — The latest ECMWF-AI, REFS, and Canadian AI models are showing a bit more snow, but it still comes down to only a dusting to a coating— much less than 3/4″. Here’s the REFS model forecast—

18z REFS forecast total snowfall for Friday. Contours are labeled (Click on image for a larger view.)

Interestingly, the REFS forecast has changed the timing from the earlier posted NBM, with light snow moving up from the south about 10 AM and taping off significantly during the early afternoon. Not much additional after 2 PM.

Friday’s “Minimal Snow” Outlook Update

Posted Thursday 12/04/25 @ 11:32 AM — A quick update on the “minimal snow” forecast by some of the models for Friday afternoon.

This “snow” was always a low probability forecast, especially when predicted accumulation is in the coating to dusting range.

The Model Blend (NBM) statistically combines the forecasts of 30-40 different models, statistically weighting each constituent model’s forecast through a comparison of how each performed over the prior 6 hours compared to the actual conditions (as captured in the 6 hour delayed URMA model). It also weights each model based on historical accuracy.

The latest Model Blend (NBM) shows almost no snow in its statistical outputs.

Here’s the mean (average) snow predicted—

15z NBM mean snowfall by late Friday evening. This is consistent with the experimental RRFS and REFS model forecasts. (Click on image for a larger view.)

Here’s the 75 percentile accumulation total. The 75 percentile means that 75 percent of the 30-40 models are forecasting at or below this amount—

15z NBM 75 percentile. (Click on image for a larger view.)

It should be noted that the low resolution ECMWF-AI still is forecasting a coating, especially for South Jersey.


This amount of snow for us doesn’t really merit the time put into it, but I’m staying in practice for later season snow events.

Thursday Update

Posted Thursday 12/04/25 @ 9:02 AM — As forecast by the REFS yesterday, a line of very light snow flurries/snow showers is expected to move through about 10 AM. It’s currently visible on radar, although much is not reaching the ground. See caption for more info—

Radar with visible Satellite superimposed at 9 AM. Much of these echoes are not reaching the ground. The superimposed RAP model Omega shows moderately strong upward motion over Philadelphia, suggesting an increase in intensity as it moves over the city into NJ. It’s then expected to dissipate. (Click on image for a larger view.)

The rest of the forecast remains on track for Thursday, as does the snow outlook for Friday.

Thursday: Cold to Colder

Posted Wednesday 12/03/25 @ 5:17 PM — This late autumn season is much different than recent previous years. It wasn’t too many years ago that I still had some hardy flowers on our deck hanging on for dear life in early December and I can remember recent years where temperatures repeatedly reached the mid 60s until the last week of December.

Thursday will likely dispel any hopes of similar warm ups in the near term. A strong cold front approaches with an increase in clouds during the morning.

Current satellite water vapor image with superimposed RAP model 500-1000 mb thickness lines (yellow), Mean Sea Level Pressure isobars (black contours) potential vorticity (fine violet contours) with superimposed MRMS RADAR. (Click on image for a larger view.)

The current air mass is dry and there isn’t much moisture to wring out in the form of showers with this front. A latest REFS ensemble member shows some light snow showers moving through Thursday morning about 10AM, just ahead of the front with some dark clouds.

The actual front moves through early afternoon with another reinforcing shot of cold air towards evening as winds pick up. Partly cloudy skies the rest of Thursday afternoon.

Friday will be cold. High temperatures on Friday may not get above 32º with wind chill temps in the mid 20s at best.

Over the past week, I’ve been watching a storm for later Friday that most, but not all, models have the snow associated with it suppressed to our south. The few models that show light snow reaching our area only crank out about 0.5″ of snow at most- a dusting or a coating. I’m watching this system and will continue to update.

After reminiscing about warmer Decembers earlier, I’m reminded that some very cold Thanksgivings and early Decembers gave way to very mild Februaries . Current cold conditions don’t necessarily portend a very cold winter.

Wednesday through Friday

Posted Tuesday 12/02/25 @ 7:20 PM — Skies clear for Wednesday. There should be plenty of sunshine and while instability cloudiness sometimes develops with an exiting storm, the models don’t show this for Wednesday.

Thursday, a strong cold front moves through mid day with just clouds at this time. Winds pick up quite a bit towards evening as temperatures plummet.

Very cold Friday, with highs in the low to mid 30s! For Friday, another coastal system is expected to move up the coast, but slide just to our south. Most models have the precipiation of this storm totally missing our area, but the ECMWF-AI model has consistently showed some light snow falling by Friday evening.

This afternoon’s German ICON model has joined the ECMWF-AI with a forecast of a dusting to a 1/2 inch coating by Saturday morning. But our GFS model and the Canadian GDPS-AI version have the precipitation passing us to our south, as does the current RRFS.

I’ll keep an eye on it.

Today’s 18z ECMWF-AI forecast for 7 PM Friday evening. Based on thickness levels and temperatures, any precipitation that falls north of the red line will be snow. (Click on image for a larger view.)
Tuesday Mix-> Rain Update

Posted Tuesday 12/02/25 @ 8:24 AM — The precipitation began as early as 6:45 AM -7 AM in our area as forecast and there was/is some ice pellets mixed in closer to/in the city.

Here’s the current MRMS “hydrometeor” scan showing various forms of precipitation —

MRMS Hydrometeor classification at 8:12 AM Hydrometeors is a catchall fancy name for ANY FORM of precipitation. For the MRMS, here’s the code meanings: BI: Biological scatterers (birds/insects) GC: Ground Clutter IC: Ice Crystals DS: Dry Snow WS: Wet Snow RA: Rain (light/moderate) HR: Heavy Rain BD: Big Drops GR: Graupel HA: Hail (often mixed with rain, noted as RH) UK: Unknown

For most of the area, this changes to all rain. The latest models show the rain ending from west to east as early as 2:30 PM to 4 PM.

Late Forecast Update

Posted Monday 12/01/25 @ 9:00 PM — Temperatures around the city have dropped below freezing (expected). The latest 00z models (HRRR NBM) are still painting a similar forecast.

But, inspection of the vertical thermal profile of the latest HRRR suggests that the early period, 7AM-9AM, may have more icy conditions or sleet closer to the city than the model precipitation type has been showing. (The models are still saying rain near the city.)

Some ground surface temperatures may be still cold enough for freezing and temperatures aloft at critical levels are still below freezing in our area at 9 AM. Snow isn’t likely, but ice pellets or some rain ice mix is. Here’s what I’m talking about—

00z HRRR with simulated radar and critical vertical level temperatures that are still below freezing at 9 AM (Click on image for a larger view.)

Just a possibility. Sometimes the model precipitation types are wrong.

Rainy Tuesday Update

Posted Monday 12/01/25 @ 4:48 PM — No significant changes in the forecast posted this morning. Here are some additional points—

  • Rain or Snow (depending upon location, see animated gif below) begins between 6 AM and 7 AM
  • Changes to all rain by late morning in most of our forecast area.
  • Little to no final accumulation in Upper Montco, Bucks, and Chester counties— areas where it had snowed.
  • Rain ends from southwest to northeast around 3-5 PM
  • Some sun breaks out in western areas before sunset.
  • Winds increase and become quite gusty towards evening.
RRFS Conditional Precipitation Type- (Snow sleet Freezing rain) 7 AM 8 AM 10 AM (Click on image for a larger view.)
Tuesday Forecast Update

Posted Monday 12/01/25 @ 9:49 AM — Last night’s models along with the early morning models continue with these trends for Tuesday’s storm. Here are the current trends—

  • Precipitation begins as light rain or light snow (north west) as early as 6 AM. Virtually no snow in NJ, in Philadelphia and immediate locales north and west.
  • Snow north and west likely changing to rain.
  • Far northwestern suburbs may have a period of freezing rain.
  • Transition to rain by late morning.
  • Heaviest rainfall in NJ.
  • No changeover back to snow expected at the end early Tuesday evening.
  • Windy early Tuesday evening.

At 8 AM most of the area will be rain—

Latest 13z NBM with precipitation type and surface temps at 8 AM. (Click on image for a larger view.)

Total Snowfall Accumulation (Model Blend, also supported by RRFS forecast)—

13z NBM (model blend) snow accumulation. (Click on image for a larger view.)

Total Precipitation (water and snow-water equivalent)

13z NBM total water precipitation (Click on image for a larger view.)
Stormy Tuesday

Updated Sunday 11:15 PM — The trend with tonight’s models is for little to no accumulation except in north and west Montco Bucks and Chester counties. It appears there will be no changeover from rain to snow towards the end of the storm. The heaviest precipitation (rain) will be in NJ. Updates tomorrow.

Originally Posted Sun 5:10 PM — This week will see the approach of a winter-like coastal storm at a time when we are still in astronomical Autumn.

Following a sunny but unseasonably cold Monday (high low 40s), clouds will increase around sunset Monday. Low pressure developing near the Gulf of Mexico (America) Mexico will lift northeastward towards our area.

12z ECMWF-AI model forecast for 7 AM Tuesday morning. The red , yellow and magenta contour lines are “critical thickness lines” which is a rough way of determining rain, sleet and snow. North of the red line (500 mb-1000mb), the atmosphere is generally cold enough for snow. North of the magenta (700-850 mb) and/or yellow (850-1000 mb) lines, the atmosphere is cold enough for sleet and/or freezing rain. The white line is the near ground level 32º freezing line.

Precipitation may start as light snow near or north and west of the city, but is expected to quickly change to rain. Northwest of the city, (Berks county, Lehigh county) the precipitation may mix with rain or stay mostly snow.

Staying with the AI model and zooming in at 7 PM, the atmosphere (based on the thickness lines) has chilled down to support some snow just north and west of the city just as the precip is raining. Note the the 32º freezing line is still far northwest, so not much of any snow is expected to accumulate on wet ground. But there’s some uncertainty.

12z ECMWF-AI model forecast for Tuesday 7 PM. Still some precip falling and the critical thickness lines are closer to the city. (Click on image for a larger view.)

So mostly rain, heavy at times, after some light snow in the morning, possibly changing back to light snow with light accumulations possible early Tuesday evening.

There’s fairly good model agreement with the track of this storm and the been good continuity between model runs.

In winter with an overall colder atmosphere, the would be a major snow storm for us. However, it’s early in the season and perhaps this year will be like last year, where there had been “not enough cold air” for major snowfalls here.

Total precipitation or snow-water equivalent will be fairly high, 1-1.3″ water.

Things to watch—

  • If the precipitation comes in early, much before daybreak (as some models are showing), we may have more snow accumulation before the changeover to rain.
  • High precipitation rates early in the storm may cause dynamic cooling, bringing temperatures near the surface closer to freezing.
  • Cold air may rush in after the main low passes, either drying things out or causing a burst of snow.

Food for thought

If the immediate PHL area will have any snow accumulation, it will occur towards the end of the storm. This is low confidence, but still a possibility.


Here’s the Model Blend forecast snowfall —

18z NBM forecast snowfall by 10 PM Tuesday evening. (end of storm) (Click on image for a larger view.)

Here’s the latest GFS forecast, just available—

18z GFS forecast for midnight Tuesday. (Click on image for a larger view.)

The latest RRFS and REFS not yet available, but the 12z RRFS was leaning towards much lower snowfall totals

An interesting early winter storm. Stay tuned for updates.

Philadelphia Area Weather Forecasts

WEEKEND WEATHER FORECAST

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Sunday Forecast Update – Tuesday Storm Overview

Posted Sunday 11/30/25 @ 9:50 AM — There aren’t any significant changes to today’s forecast from what I posted Friday evening. Light rain moves in from the west around 11 AM and moves out to the east by about 2-3 PM. It remains cloudy, but a few bright spots through clouds are possible in the later afternoon. Total rainfall light, between 0.04″ and 0.10″ today.

Regular visitors here know I’ve been talking about a winter-like coastal storm that is expected to move in Tuesday morning. The ECMWF-AI model has some light precipitation, possibly some snow flakes or sleet before daybreak which changes to all rain in the city and immediate surrounding counties. Upper Bucks, Montco and Chester counties may see perhaps a 1/2″ of snow accumulation before the changeover between 9 AM and 11 AM. The latest RRFS (still experimental) has it somewhat warmer with accumulations limited to the Allentown, north and west.

At times, the models have suggested a changeover back to snow before ending Tuesday evening, but that possibility seems to have faded at this time.

Here’s the current RRFS snowfall forecast at 11 AM Tuesday

06z RRFS snow accumulatioin forecast for Tuesday morning. The RRFS tends to run a bit warm, so this may be underestimating snowfall. (Click on image for a larger view.)

I’ll update later this afternoon with a more complete forecast based on the latest models. Stay tuned.

Interesting Weather through Tuesday

Originally Posted Fri 7:10 PM — An interesting weather pattern is expected to begin this weekend with a deepening upper trough and spawning of low pressure.

Saturday Forecast

Cold high pressure will be in control for Saturday. Most of the day to be sunny and still unseasonably cold. Windy in the morning, but winds subside during the afternoon into the evening. Some cloudiness moves in before sunset ahead of the next system.

NBM high temperatures: Blue Bell, PA 42º Philadelphia, PA 43º
Very low uncertainty (based on standard deviation): ± 0.6º

Sunday Forecast

Clouds move in Saturday night and Sunday begins cloudy from a system in the Great Lakes

12z NAEFS forecast for Sunday morning. Rain ahead of another cold front. (Click on image for a larger view.)

Increasing likelihood of light rain from west to east as early as 11 AM. Light rain through the afternoon, ending about 6 PM in the city. Total rainfall 0.15″- 0.45″

NBM high temperatures: Blue Bell, PA 46º Philadelphia, PA 48º
Above average uncertainty (based on standard deviation): ± 2.4º

Stormy on Tuesday

The cold front that move through brings in colder air for Monday and a dip in the jet stream spawns low pressure the moves up towards us on Tuesday.

12z NAEFS forecast for Tuesday morning with “critical thickness” lines. (Click on image for a larger view.)

Note the red, yellow, and magenta “thickness” lines running through the Philadelphia area. This suggests that the lower and mid levels of the atmosphere are cold enough for frozen precipitation. Areas far northwest of the city will likely see some snow accumulation. Areas closer to the city may see some snow or sleet change to rain. Little to no accumulation expected in the city at this time.

This is an interesting winter-like storm for this time of the year. I’ll be following it over the coming days. Check back for updates.

Philadelphia Weather Outlook

THIS WEEK’S WEATHER

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Weekend Outlook- Tuesday Storm Outlook

Posted Friday 11/28/25 @ 10:08 AM — Today, Friday, will be windy and continued cold. Mostly sunny skies are expected, although some instability cloudiness is possible late afternoon in western sections of the Philadelphia adjacent counties. Highs 40-42º.

For the Eagles game— Winds 14 mph Gust 28 mph at 3:30 PM

06z RRFS forecast for Sports Complex Area, Philadelphia. (Click on image for a larger view.)

Saturday will be less windy but still cold.

Sunday– light rain beginning late morning into the afternoon.

Tuesday: Possible snow/sleet and freezing rain in the morning. Additional information this evening in my regular Weekend Weather Forecast.

Weekend and Storm Outlook

Posted Thursday 11/26/25 @ 7:20 PM — Friday looks to be continued chilly and somewhat windy. Saturday will be less cold and less windy. Some light rain is expected by Sunday early afternoon.

Of interest is our first setup for possible frozen precipitation in far northern and western suburbs. (A pattern like this in a few weeks could result in a potential snowstorm.)


ECMWF forecast form Tuesday afternoon.
Wednesday Evening & Thanksgiving Outlook

Posted Wednesday 11/26/25 @ 10:28 PM — One thing I left out in Thursday’s forecast below— it will be mostly cloudy with just a few peeks of sun.

Posted Wednesday 11/26/25 @ 5:13 PM — A line of showers and storms are just to our west and will move in about 5:30 to 6 PM. They are fast moving but some areas may receive as much as 0.2-0.3″ of rain. Winds pick up this evening after 7 PM with gusts 35-45 mph.

Radar at 5:01 PM (Click on image for a larger view.)

Thanksgiving day looks to be windy and colder, as does Friday. High temperatures on Thursday only in the lower 40s!

The winds calm down for Saturday but a rain storm is expected for Sunday afternoon. Details on the weekend tomorrow.

ECMWF-AI forecast for 1 PM Sunday. Rain ahead of another cold front/warm front. (Click on image for a larger view.)
Wednesday Forecast Update

Posted Wednesday 11/26/25 @ 8:20 AM — The models have not been doing well forecasting the current system. A large area of rain that had been forecast for much of Southern NJ (and part of PHL) this morning has instead moved about 40 miles to the east of its forecast track.

RADAR image 7 AM showing rain moving far to the east of where it had been forecast. (Click on image for a larger view.)

Clouds are expected to break for sun early afternoon before additional clouds move in mid to late afternoon ahead of the cold front. Showers are forecast in Philadelphia around 6-8 PM, but this continues to be a low confidence forecast. High wind gusts are expected with the front.

REFS Ensemble member forecast at 6:30 PM (Click on image for a larger view.)
Wednesday Forecast

Posted Tuesday 11/25/25 @ 5:37 PM — The rain associated with the warm front will become heavier early this evening and will move out of the area by midnight.
Another wave is expected ride up near the area Wednesday morning. The rain is expected to fall from the Delaware Rive and eastward into NJ. Only the eastern part of Philadelphia may see this rain according to the NAM-NEST and the RRFS.

The model blend (NBM) does have this second wave of rain falling more westward, over Philadelphia, ending about 9- 10 AM Wednesday

Wednesday will be warm with periods of sun and clouds. High temperatures will reach 65º-68º

18z NBM (model blend) high temperatures for Wednesday (Click on image for a larger view.)

Another line/area of rain will develop ahead of the cold front. Some models show this as early as 4 PM; others delay it to about 7-8 PM.

Temperatures slowly fall Wednesday night. High temperatures on Thanksgiving Day will be in the morning….temps fall throughout the day to the 30s by early evening.

Tue 5:21 PM —Forecast Review —Not my best forecast, nor the best forecast for the REFS or HRRR today. The rain came in as forecast last night (1-3 PM), not as forecast this morning. Here’s the radar at 2 PM—
Radar composite image with RAP model Omega parameters overlay at 2 PM. (Click on image for a larger view.)

I’m always interested in why that happens and whether there was any sign that the newer forecast couldn’t be trusted. It’s interesting that the HRRR and RRFS / REFS continued with the later rain onset even with the morning model (12z and 15z) runs.

This morning’s NAM-NEST (06z and 12z model runs) more accurately predicted the rain onset between 12 PM and 2 PM. My take-away is that the RRFS/REFS and the HRRR seem to over-delay precipitation onset with warm fronts. We had a similar forecast issue with the last warm front that brought ice pellets to our area a week or so ago.

Tuesday Rain Update

Posted Tuesday 11/25/25 @ 9:27 AM —Last night’s models continued a trend where the rain initially shears off to our north and west during the afternoon. Based on the REFS (which incorporates the HRRR), the current start time for light rain is now between 3PM and 6 PM in the city. The previous start time of 1-3 PM now applies to far northwest Montco and Bucks counties.

06z REFS forecast Rain Probability 6 PM (Click on image for a larger view.)

I’ll update later this afternoon with Wednesday’s forecast which continues to be somewhat of a mix of sun, clouds and showers.

Tuesday into Wednesday

Posted Monday 11/24/25 @ 8:17 PM — The warm front will be approaching on Tuesday with increasingly cloudy skies. The onset of the rain varies somewhat from model to model, but I’m leaning on the REFS for the timing. Very light rain starts between 2-3 PM near the city, earlier to our west.

18z REFS forecast probability of light precipitation (0.01″) at 3 PM. I find that with hourly probability forecasts, 20-25% % or greater is a good indicator of some precip. It should be mentioned that some models show as early as noon and as late as 4-5 PM.

The general trend is for the rain to start very light here with somewhat heavier rain after 8 – 9 PM Tuesday evening into the night.

Mild temperatures (60º-65º) and a mix of sun and clouds on Wednesday. Additional showers expected late afternoon Wednesday before the cold front moves through about 9 PM with gusty winds. Temperatures drop after the front.

It’s unclear whether a line of showers will form with the actual cold front.

Models guiding this forecast: GFS . REFS, ECMWF-AI,

Thanksgiving Week Outlook

Originally Posted Sun 8:44 PM —The next system to affect us moves in Tuesday into Wednesday with a warm front and its associate rain Tuesday afternoon into night followed by a cold front Wednesday evening. Here’s the setup:

GFS forecast for Tuesday afternoon. Warm front approaches from the south. Rain mid to late Tuesday afternoon into early Wednesday morning. Partial clearing Wednesday with some sun and quite mild. A strong cold front move through Wednesday evening (7-10 PM) with more showers and high wind gusts. (Click on image for a larger view.)

Monday: High pressure builds in for mostly sunny skies. Some high cloudiness in the mid to late afternoon as warm air moves in aloft.

Tuesday: Clouds with rain/showers moving in about 1-3 PM from the west.

Wednesday: Some clearing with sunshine. Then clouds later afternoon with approaching cold front. Windy and gusty with showers Wednesday evening. Highs about 62º

Thursday: Mostly sunny, windy and chilly. Some instability cloudiness likely.

Friday: Mostly sunny and cold.

Temperatures (Model Blend)

11-24-25 00z NBM temperatures/dew points for KLOM Blue Bell, PA (Click on image for a larger view.)

Weather… and Other Things 'Up in the Air'