Philadelphia Area Weather Forecasts

WEEKEND WEATHER FORECAST

Forecast Review— Looking north and looking south at 2 PM from Fort Washington State Park. Dark clouds south; clearing and sun north. A couple of spits of rain on the way there!
Left- North view clearing                  Right- South view clouds

Update Sat @ 11:25 AM — It looks like another upper air disturbance will affect southern parts our area this afternoon.

Water Vapor image 11 AM shows upper air disturbance (white boxed) moving towards us, perhaps just south. Additional upper air disturbance in left lower corner of image may be the trigger for evening showers forecast by the NAM-NEST, mentioned in the forecast review below. (Click on image for a larger view.)
Update Sat @ 11:02 AM —Forecast Review— I’m waiting for the clearing I had predicted. The morning model runs are in lower consensus than previous runs. It looks like the dividing line will be right through Philadelphia—
This morning’s HIRESW-FV3 shows the north-south gradient dividing line between sun- clouds – showers for 2 PM (Click on image for a larger view.)

Adding more confusion: this morning’s NAM-NEST shows showers breaking out again about 6 PM around Philadelphia!

Updated Sat 8:46 AM — Last night’s 06z models continue with the general forecast of rain having mostly ended in Philadelphia. Water vapor imagery and current MRMS radar suggest another wave may bring some showers from Philadelphia on southward, but according to the models, precip ends in this area about 11 AM -12 this morning and clouds break/thin for some sunshine by 12-2 PM.

Updated Fri 10:46 PM — Tonight’s early models continue with the rain ending in the immediate PHL area in the morning. In fact, tonight’s NAM-NEST has the rain ending early morning Saturday with sun by late morning.  The  NAM-NEST is looking very similar to the the earlier Canadian HRDPS below.

Previously Posted Fri 5:10 PM —

There’s been some clarification on the rain and clearing for Saturday. Things are looking better.

Saturday

It appears that most of the immediate Philadelphia area will get rain/showers over the night time hours. The strong rainfall gradient north to south continues. Areas north of Philadelphia will have relatively little rain. Areas south and far south will have heavier rain lasting longer. Rainfall ends as early as 10 AM -12 noon.

The latest NAM-NEST has the most optimistic forecast.

A few pictures are worth a thousand words—

Today’s 18z NAM-NEST shows clouds (black) simulated radar (green-blue) and accumulated rain (green contours) at noon. Much of the northern suburbs will be in sunshine fairly early! (Click on image for a larger view.)

Today’s 12z Canadian HRDPS showing a rain shield even further south at 10 AM.

Today’s 18z HRRR at 8 AM Saturday. More clouds, but rain showers taper off in the morning. (Click on image for a larger view.)

While the rain ends early it remains to be seen how quickly the clouds will break. Northern locations will have earlier sunshine.

High temperature 75.1º ± 2.7º NBM model Blue Bell, PA

Sunday

Sunny. Light easterly winds.

High temperature 81.9º ± 1.3º NBM model Blue Bell, PA