Category Archives: Philadelphia Weather Outlook

Philadelphia Weather Outlook

THIS WEEK’S WEATHER

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#Philadelphia #weather #PAwx #drought

Philly Drought Watch

Posted Friday 10/25/24 @ 11:28 AM — Our next chance of any rain appears to be the first few days of November. Unfortunately, the latest AI and ensemble models show an upper air ridge in our area that may seriously reduce the amount of rainfall we get ahead of a cold front.

Here’s the ECMWF-AIFS forecast for November 2

ECMWF-AIFS (Artificial Intelligence Model) forecast for 8 PM Saturday Nov 2nd. Light showers ahead of a cold front, dissipating as they move eastward. (Click on image for a larger view.)

Here’s the GFS AI model forecast for Sunday Nov 3rd—

GFS Graphcast AI Machine Learning Model forecast for Sunday Nov 3 at 7 PM. Again, upper ridge will reduce our rainfall potential. (Click on image for a larger view.)

On the more positive side is the NAEFS (ensemble model combined GEFS and Canadian ensemble). It’s forecasting more rain and possible coastal tropical system near Florida. Likely not correct—

NAEFS forecast for Wednesday Nov 6th . Tropical system hinted at near Florida coasts. (Click on image for a larger view.)
The Drought Continues

Posted Thursday 10/24/24 @ 5:01 PM — I can’t remember the last time I saw so many large sprawling high-pressure systems on the weather map. Our dry weather is expected to continue into the first few days of November.

Until that time, we’ll have some colder periods towards the end of this weekend as a second cold front moves through early Saturday. We’ll see another warm-up next week. And mostly sunny skies shall prevail.

I may have to rename this blog, “The Rain Watch”. I’m currently using various statistical ensemble models and the ECMWF-AI and GFS-AI models to see about our next chance of rain

We may finally get some rain, albeit, hardly a drought-buster, sometime in the November 3rd through November 5th time frame.

Here’s the ECMWF-AIFS forecast for November 3—

ECMWF-AIFS forecast for 7 AM November 3. A cold front moves through with about a quarter inch of rain, possibly more if low pressure develops along the front. (Click on image for a larger view.)

Posted Tuesday 10/22/24 @ 4:27 PM — As mentioned yesterday, two cold fronts will move through in the coming days; one late Wednesday night into Thursday and another late Friday night into Saturday.

These frontal passages have been forecast to be dry, but today’s ECMWF and Canadian RGEM show a deeper trough moving through with enough lift for with some sprinkles, mainly in NJ late Wednesday night. The few sprinkles forecast are supported by the experimental REFS. (The ECMWF-AIFS shows no showers.)

We’re only talking a one or two hundredths of an inch in a few locations.

During the weekend, our current well above average temperatures will drop to noticeably cooler levels.

The GraphCast AI-Machine Learning version of the GFS has moved the chance of rain here further down the road into November from yesterday’s forecast. So the drought continues.

10-22-24 00z Graphcast-GFS forecast for Monday, November 4th. Our first chance of light rain?? (Click on image for a larger view.)
No Rain

It’s been a long time since things seemed so dry outside. And the current extended range forecasts keep thing dry for us over the next two weeks!

Yes, there will be two cold fronts moving through this week. The first one will result in a familiar pattern of having any rain shear off to the far north and west of the city—

Today’s ECMWF shows showers only far north of the city. (Click on image for a larger view.)

Another cold front moves through Saturday. The models had been forecasting some light showers for us, but those have all but disappeared in the forecast—

Today’s GFS forecast for Saturday. Grey black is cloud cover. Essentially no rain with this front. (Click on image for a larger view.)

I’m still playing with the highly experimental AI-Machine Learning version of the GFS. It still seems to show the first chance of any substantial rain here is November 3rd!

Graphcast GFS (AI Machine Learning model ) forecast for November 3rd. (Click on image for a larger view.)

All I can say is “Wow”.

Philadelphia Weather Outlook

THIS WEEK’S WEATHER

#Philadelphia #weather #PAwx #Milton

Hurricane Milton Update

Posted Wednesday 10/09/24 @ 4:31 PM —The latest models are suggesting Milton will make landfall between 11 PM and midnight, just south of Tampa Bay, possibly closer to Sarasota—

12z HAFS B wind/pressure forecast for 11 PM tonight. Landfall between Sarasota and Tampa Bay. (Click on image for a larger view.)

There remains uncertainty in the exact location of landfall. Here’s a few models—

Milton Landfall – various models (Click on image for a larger view.)
Hurricane Milton Update

Posted Wednesday 10/09/24 @ 9:55 AM —Both the latest ECMWF AI model and NOAA’s newest hurricane model, the HAFS B, has Hurricane Milton making landfall between 10 PM and midnight south of Tampa Bay, closer to Sarasota—

The latest HAFS B model wind/pressure forecast for ~10 PM tonight (Click on image for a larger view.)

Here’s the ECMWF-AIFS has been consistent with this landfall location—

06z ECMWF-AIFS wind/pressure forecast for ~ 10 PM tonight (Click on image for a larger view.)

The hurricane intensity models all have Milton downgrading to a Category 3 before it makes landfall.

A landfall south of Tampa Bay may be better for the Bay area as wind flow will be westward instead of eastward in that region. It will be worse for Naples, Venice, etc.

Hurricane Milton Update

Posted Tuesday 10/08/24 @ 4:27 PM — The latest ECMWF has delayed Milton’s landfall until 7 AM Thursday morning, closer to Sarasota. The AI version is similar—

12z ECMWF Milton landfall around 7 AM Thursday morning just north of Saratoga (Click on image for a larger view.)

NOAA’s newest hurricane model, the HAFS B has an earlier landfall further north near Tampa Bay—

12z HAFS B forecast for midnight Wednesday into Thursday morning. (Click on image for a larger view.)

Posted Tuesday 10/08/24 @ 3:00 PM — Today’s models have trended towards a somewhat later landfall for Milton, sometime in the early morning hours of Thursday.

Here’s NOAA’s high resolution Hurricane model, the HWRF, one of several NOAA hurricane-specific models—

Todays 12z HWRF model wind speed and surface pressure forecast at 5 AM. Notice the northward track of this model. with landfall north of Clearwater. (Click on image for a larger view.)

There’s still a range of landfall predictions and there’s no reason to believe this is the correct one.

Posted Tuesday 10/08/24 @ 10:41 AM — The latest ECMWF-AIFS model shows Hurricane Milton reaching landfall just before midnight Wednesday into Thursday near Sarasota. This AI model has been extremely consistent in forecasting this storm and consistent about its track.

10-08-24 06z ECMWF-AIFS forecast for Thursday at 12:01 AM. Rainfall shading (Click on image for a larger view.)

In contrast, the GFS is slightly north, directly entering Tampa Bay—

10-08-24 06z GFS Winds at 12:28 AM Thursday. Slightly north of the ECMWF-AIFS, forecast track, entering Tampa Bay. (Click on image for a larger view.)
Hurricane Milton Update

Posted Monday 10/07/24 @ 5:20 PM —The latest ECMWF-AIFS has become available. I’m leaning towards this model because it was the first to forecast this hurricane over a week ago and it did quite well with forecasting Helene’s track.

The latest ECMWF-AIFS takes the storm just north of Sarasota about 10 PM to midnight Wednesday—

10-07-24 12z ECMWF-AIFS forecast for 10 PM Wednesday evening. Shading is rainfall rate. (Click on image for a larger view.)

Note that our GFS model is significantly further north with Milton’s landfall and is somewhat slower, making landfall about 2 AM Thursday—

10-07-24 12z GFS has a track further north and somewhat slower, reaching landfall north of Clearwater at 2 AM Thursday. (Click on image for a larger view.)

The operational version of the ECMWF is closer to the GFS than it’s own AI version.

Just an acknowledgement that this is a dynamic situation, no single model should be relied upon and the official information from the National Hurricane Center should be utilized.

Quiet Here Weather-wise. And then there’s Milton

If I had some time off as a meteorologist in the northeast, this week would be a great time to take an extended vacation.

Fair weather and no significant rainfall for our area for at least a week!

A very amplified high pressure ridge will fill the central and western US while the northeast will be under the influence of an upper trough—

Monday morning Water Vapor image with superimposed RAP model parameters. Upper trough over our area, strong blocking ridge over the central and western US. Hurricane Milton visible. (Click on image for a larger view.)

By Wednesday, the upper low closes off to our northeast and nothing but dry high pressure is available to affect our weather—

NAEFS forecast for Wednesday at 2 PM. Large ridge and high pressure to affect our weather. (Click on image for a larger view.)
Hurricane Milton

The ECMWF AIFS had successfully predicted the formation and likely track of what is now known as Hurricane Milton well over a week ago. It did this long before the regular models showed any specific development. It also was very successful with the general track of Helene.

The ECMWF-AIFS latest run shows the following possible landfall between 8 PM Wednesday and 1 AM Thursday—

10-07-24 06z ECMWF-AIFS forecast for Hurricane Milton at 8 PM. Milton shows signs of weakening somewhat as it approaches south of Tampa Bay. (Click on image for a larger view.)

More updates on Milton later today.