Welcome to autumn, as the fall season officially arrived at 3:21pm Wednesday afternoon. It certainly didn't feel like it however, with a warm and sticky transition from summer to fall as highs soared to 80 to 85 degrees for most spots outside of the Poconos. It was a meteorological hodgepodge of clouds, breaks of sun, and a few passing showers, a precursor to a soaking and occasionally heavy rain that is in store for the first full day of fall on Thursday.
A slow moving cold front will bring a period of steadier rain, with some heavy downpours and a gusty thunderstorm in spots as well, Thursday into Thursday night, before sliding off the coast on Friday. A widespread 1 to 3 inches of rain is possible, higher totals the farther west you travel, and there could be some localized flooding as well.
As our front departs on Friday, it will sweep the rain, clouds, and humidity away just in time for the first weekend of fall, which looks to feature dry and pleasant weather with lots of sunshine and the refreshingly low humidity that is synonymous with autumn. Expect comfortably mild highs in the low 70s, with overnight lows close to 50 degrees.
The first full day of fall looks to be pretty wet, with increasingly steady and occasionally heavy rain as the day progresses. We'll watch a cold front slowly crawl east across Pennsylvania late Thursday and then into New Jersey by Thursday night. Out ahead of it, expect periods of rain and some tropical downpours, and up to a few inches of rain are likely for much of the area.
Flash flood watches are posted for everyone north and west of the Interstate 95 corridor, where the heaviest rain is expected. Rainfall totals will decrease as you move closer to the coast.
A widespread 1 to 3 inches of rain is likely, closer to 1" towards the shore with the best chance for 3" or locally higher amounts farther west, especially into central Pennsylvania.
A gusty storm could produce some damaging winds or even an isolated tornado. Rain will taper off from west to east Thursday night.
We'll dry and clear things out on Friday, but it may be a slow process. So you'll wake up to clouds and maybe a shower around early Friday, especially east of the Delaware River into New Jersey, then clouds will break for some sunshine by Friday afternoon.
Highs will be closer to 70 degrees, with a westerly breeze helping to dry and clear us out, as well as lower the humidity levels back into the comfy range.
SATURDAY AND SUNDAY
The first weekend of fall should have more of a fall-ish feel to it, with partly to mostly sunny skies, lower humidity behind our late week front, and highs in the low 70s. Overnight lows will dip into the low 50s each night, which means cool and comfy sleeping weather.