With fresh rounds of downpours, water rescues, road closings, and stream flooding, the first day of the astronomical fall in the Philadelphia region on Thursday felt like so many eventful days of the astronomical summer.
At least there were no tornadoes.
As opposed to the rains associated with Fred, Henri, and Ida, this time they came in anonymity, developing in bands of “training” storms ahead of a potent front that was rather precocious for so early in the season, according to the National Weather Service.
Numerous water rescues were reported on both sides of the Delaware River. The list of temporary road closings and flood-related lane restrictions included the Broad Street exit off I-95 and the Vine Street Expressway near Broad Street. Roads in Media, Delaware County, and Northfield, Atlantic County, were underwater for a time.
While this was no Ida, rainfall rates — in some cases an inch or more in half an hour — were “reminiscent” of those usually associated with tropical storm remnants, said Jonathan O’Brien, meteorologist at the National Weather Service Office in Mount Holly.
“This was quite a sizable event,” O’Brien said.
More than an inch fell into the official rain gauge at Philadelphia International Airport between 1 and 2 p.m.
Among the streams that reached flood stage or sloshed over were the Cobbs and Frankford Creeks in Philadelphia; the East Branch of the Brandywine, in Downingtown; and the Poquessing Creek, in Bucks County.
The storms were set off by a rather ponderously moving front, O’Brien said, and once they formed they moved almost due south to north through the afternoon. “The system overall was very slow-moving,” he said, thus “these cells were just able to train up over one another.”
While some areas were getting deluged, “there were some gaps” that spared parts of the region from the heavier rains.
If it seems as though we’ve had a lot of days like this in the last few months, we have.
According to the weather service’s archives of advisories, this was the 25th day since June 3 on which it issued flash flood warnings in its service territory, which covers Delaware, eastern Pennsylvania, and most of New Jersey.
Before June 3, it had not issued one since August 2020.
The heaviest rains moved north of the region by day’s end and they were due to shut off by Friday morning. Dry days with more seasonally appropriate temperatures will follow, O’Brien said.
“It will definitely feel more like fall,” he said.