Philly is under a severe-storm watch Friday, to be followed by frost and real fall weather
Expect a 100% chance of October weather, and that should be good for the foliage show.
In advance of the chilliest air mass of the season, potent thunderstorms are possible late Friday afternoon into the evening, and then major changes are in the winds.
The federal Storm Prediction Center has issued a severe-thunderstorm watch for the entire region until 8 p.m., warning that gusts approaching 60 mph are possible.
In addition, “We can’t rule out a stray tornado,” said Joe DeSilva, meteorologist in the National Weather Service’s Mount Holly office.
And then expect about 100% chance of October, with frost looking likely Sunday morning.
Said DeSilva, “Finally, some real fall weather.”
When severe storms might arrive in Philly
The prime time for any severe storms would be between 5 and 7 p.m., said DeSilva.
Temperatures climbed well into the 70s Friday afternoon as the sun made a reappearance, but the retro-summer is about to end.
Frost is likely in the region Sunday morning
After the rain shuts off Friday night with the passage of a powerful front, temperatures are due to tumble into the 40s, and on Saturday may get stuck in the low 50s, or about 30 degrees cooler than the highs on Friday.
For the thousands participating in the annual Philly Bike Ride, the trip to the hills of Manayunk might be a challenge: Winds from the north are forecast to gust past 35 mph throughout the event.
Winds back off and temperatures drop Saturday night. Early Sunday they could drop into the low and mid-30s, said DeSilva.
If skies remain clear and winds are light enough to allow the daytime heat to escape, patchy frost is likely to coat the car roofs and ground foliage in the region.
A “freeze watch” for subfreezing readings has been posted for northern and western sections of Bucks, Chester, and Montgomery Counties.
Highs Sunday are forecast to be in the mid- to upper 50s, which would be about 10 degrees below normal.
Temperatures during the workweek could get no higher than the mid 60s, with nights in the 40.
And it should be looking more like fall.
The Philly region’s peak foliage-color period is a bit away, based on the behavior of recent seasons, but the show should be getting a boost,
“I expect the cooldown to have a major effect on foliage in southeastern Pennsylvania,” said Ryan Reed, program specialist with the Pennsylvania Department of Conservation and Natural Resources, and author of its weekly foliage updates.
“By this time next week, there should be a lot of color in Philly,” he added.
Based on what has happened to the north, it could be quite a show.
“This season has been awesome so far,” he said, “one of the best in recent memory.”
