Monthly Archives: October 2023

Philadelphia Weather Outlook

THIS WEEK’S WEATHER

#Phillywx #Philadelphia #weather #PAwx

Fri 5:52 PM Forecast Review — What was the story with all those clouds and light sprinkles today? I know I didn’t post a specific forecast for today, but I also know it wasn’t in the TV or radio forecasts last night. Will anyone acknowledge a wrong forecast?

The nice weather has allowed me to take a break in my daily updates. But I’m returning my attention to forecasts with my regular Weekend Weather Forecast later this evening. Stay tuned.

Could the Weather be any Better?

Update Thu 10/26 9:35 PM — The weather doesn’t get much better than this, and I haven’t posted much this week since everything you need to know about the weather can be learned by walking outside.

Temperatures have been running a few degrees warmer than forecast earlier this week and it looks like we’ll hit the low 80s by Saturday.

The only uncertainty was/remains regarding possible showers on Sunday and it looks like showers may stay to our far north and west. That’s the most likely scenario, but still some room for that forecast to change. Weekend Weather returns later tomorrow.

Mild Weather Continues

Updated Tue 10/24 @ 7:44 PM — The upper ridge is building, with warmer air moving towards us at all levels of the atmosphere. The storm path is to our north and a disturbance moving through Canada will bring some periods of clouds on Wednesday, mostly after noontime. There should still be plenty of sun too. High temperatures Wednesday through Thursday in the low to mid 70s, possibly higher on Friday.

Water Vapor image late Tuesday afternoon shows the disturbance that will move to our north on Wednesday with some mid-level cloudiness at times. (Click on image for a larger view.)
Beautiful Weather

Updated Mon 10/23 @ 10:02 AM — The upper level ridge will move north and eastward this week, giving us beautiful weather through Saturday!

Current satellite water vapor image with superimposed RAP model 500-1000 mb thickness lines (yellow), jet level wind streamlines (orange contour-arrows) potential vorticity (fine white contours) and superimposed MRMS radar. Yellow contours capture the average temperature-density of the air mass and provide a horizontal cross-sectional view that allows a three dimensional conceptual outline of the dome of warm air. This dome will advance towards us, as surface high pressure builds over the eastern US. (Click on image for a larger view.)

High temperatures on the upswing this week—

Today’s 12z NBM Model Temperature Dew Point meteogram for location Blue Bell PA (Click on image for a larger view.)

Previously Posted Sun 6:03 PM —

Our current, cool weather is the result of a cyclonic flow around the departing low pressure system along with an upper level trough—

NAEFS model- Sunday’s current jet flow shows a cyclonic flow/departing upper level trough over us that will be lifting out this week, transitioning to an upper level ridge. (Click on image for a larger view.)

This week, we’ll transition to an upper level ridge in our area, allow temperatures to warm above seasonal averages—

By Thursday, the NAEFS model jet level winds (250 mb) shows an upper level ridge over our area with high pressure at the surface. Sunny skies and mild temperatures expected for most of the week, likely lasting into the weekend. (Click on image for a larger view.)

October often has the best weather and we’ll likely see that this week. High temperatures above 70º by Thursday!

Philadelphia Area Weather Forecasts

WEEKEND WEATHER FORECAST

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Sunday Forecast Update

Update Sun 10/22 9:18 AM — The model guidance has backed off on the cloudiness today. Mostly sunny. Maybe some cloudiness towards sunset.

Updated Sat 10/21 @ 5:41 PM — The light showers that had been expected to move through Sunday morning will stay to our south—

Today’s 18z HRRR shows the clouds and rain to our south at 8 AM Sunday morning. Similar forecast with the HRDPS. (Click on image for a larger view.)

Periods of cloudiness and sunshine in the afternoon. Cooler on Sunday with highs 56º (Blue Bell) 58º (Philadelphia).

Saturday Weather Update

Updated Sat 10/21 @ 10:08 AM — The upper trough will swing through today. Disturbances (areas of vorticity and potential vorticity) will move through causing occasional cloudiness and even a few sprinkles this afternoon.

Current satellite water vapor image with superimposed RAP model 500-1000 mb thickness lines (yellow), potential vorticity (fine white contours) and superimposed MRMS radar. The upper trough (RED dashed line) will rotate through today. An weak low pressure system (L) is expected to move through Sunday morning with showers in the morning.

Clouds should thin for some sunshine about 11 AM, but periods of cloudiness will return mid afternoon. Some light sprinkles are possible in a few areas.

Previously Posted Fri 6:11 PM —

A low pressure system off of the New England coastline will move away as a cold front moves through tonight. Skies should partially clear Saturday, but a general cyclonic flow with embedded disturbances will affect us this weekend causing periods of cloudiness and a widely scattered light fast moving shower. It will be VERY WINDY.

The current water vapor image shows the line of showers ahead of the cold front that will move through this evening ( Friday), about 9 PM. Much of the heavier rain will move up to our northwest —

Current satellite water vapor image with superimposed RAP model 500-1000 mb thickness lines (yellow), potential vorticity (fine white contours) and superimposed MRMS radar. The white arrow shows the expected path towards us of a weak area of low pressure, now in Canada,

For Saturday—

Current Canadian RGEM forecast for Saturday at noon. Rain has departed, clouds and sun in our area. The low pressure system expected to move through Sunday morning is in Wisconsin. (Click on image for a larger view.)

Saturday

Clouds break for sunshine by 9 AM. It will become VERY WINDY with gusts exceeding 40 mph. Clouds move back in some areas, especially south of the city. Areas in Chester and Delaware counties may see some light, fast moving showers about 2 PM. Wind gusts near or above 40mph.

High temperature 63º ( NBM model— location Blue Bell, PA)
High temperature 64º ( NBM model— location Philadelphia, PA)
Low uncertainty of ± 0.7º

Sunday

Additional light showers may move through Sunday morning with another disturbance. Then a mix of clouds and sun in the afternoon. Continued windy.

High temperature 58º ( NBM model— location Blue Bell, PA)
High temperature 60º ( NBM model— location Philadelphia, PA)
Average uncertainty of ± 1.7º

Wind Meteogram
Today’s NBM 18z wind meteogram for Blue Bell, PA (Click on image for a larger view.)