With the echo-chamber weather forecasts persisting — as in showers likely, showers likely, showers likely — flash-flood watches remain in effect until 8 a.m. Wednesday.
Flood warnings and advisories were in effect Tuesday morning in parts of Bucks, Chester, and Montgomery Counties after fitful overnight downpours
And don’t be surprised if the National Weather Service issues those watches until the end of the workweek. The atmosphere has the region captured in the rinse cycle, with episodic downpours possible at almost any time.
“You have this moisture in place that’s just not going anywhere,” said Dave Dombek, a meteorologist with AccuWeather.
For widespread rains, Dombek says he would bet on Wednesday, when the overall pattern would be favorable for giving everybody a dousing.
For now, the rain remains capricious. All the wetness is related to a system that often results in long-enduring summer heat: High pressure off the Atlantic Coast that often bakes the region and sets off heat waves.
In this case, however, it is serving as a block for a complex series of moisture-bearing systems. Its influence might nudge just far enough west to keep areas from the I-95 corridor to the Shore mostly rain-free on Monday.
But that’s no sure thing as the air is so full of “precipitable water” that some of it could be wrung out at most any time.
During the weekend, what Dombek called a “hybrid” nor’easter — which behaved more like a tropical storm — jogged inland and deluged areas to the west of Philadelphia, including western Chester County.
Close to 3 inches of rain was reported in Kennett Square, and deluges led to numerous water rescues. The National Weather Service reported water rescues near West Grove. No drownings or injuries were reported.
Areas of Schuylkill County evidently were swamped literally, with up to 4.8 inches of rain reported. Here is video from Tremont.
“It would have been a helluva snowstorm,” said Dombek.
But believe it or not, rainfall for the last 30 days has been substantially below normal in Philadelphia, Delaware County, and in the South Jersey neighboring counties.
That’s more than likely to change based on forecasts having the odds favoring showers through Thursday, with up to 4 inches of rain possible.
So far, no major flooding has occurred in the region. As of noon Monday, only the Brandywine Creek at Chadds Ford was out of its banks at 9.79 feet; flood stage is 9 feet.
For now, at least, all the moisture is holding off any chance of a heat wave, but when it’s not raining the air will remain swollen with steamy water vapor.
Said Dombek, “You’re still going to be running your air conditioner.”