Downpours erased the Philly region’s 30-day rain deficits, but drought watches remain

The drought watches remain in effect, but this week’s rains all but wiped out the short-term precipitation deficits that had been growing disturbingly on both sides of the river in the last month.

“Definitely, everybody in the area got something,” said Brad Carlberg, meteorologist at the Middle Atlantic River Forecast Center in State College, which tracks countywide rain totals using a sampling of reporting stations.

A big winner was Montgomery County, which started the week with rainfall that was a third of normal during the previous 30 days. After widespread rain Tuesday and Wednesday, the 30-day total jumped to nearly 4.6 inches, 115% of normal, according to the river center.

» READ MORE: A drought watch is in effect in much of Pa.

The Jersey Shore counties, which had been as dry as sand dunes, also prospered. Cape May County went from 22% of average to 98% for the 30-day period, with 3.5 inches of rain.

It was quite a turnaround. Several individual stations reported more than 4.5 inches on Tuesday alone, when the heaviest rain fell, and the downpours had an element of summer caprice, with totals varying wildly within counties.

However, smoothing out the differences suggests that that soils and streams throughout the region received a beneficial recharge, while avoiding major flooding. Through Wednesday every county was at or well above 30-day normal rainfalls.

Still, officially the region’s “abnormally dry” zones on the U.S. Drought Monitor map expanded significantly with Thursday’s update. However, that analysis is performed on Tuesdays.

Based on Thursday’s precipitation, groundwater, and surface-water indicators, Chester County would no longer qualify for the drought-watch party. Its 30-day total through Wednesday was 138% of normal. But any decision to drop counties would be made at next week’s Drought Task Force meeting, said Pennsylvania Department of Environmental Protection spokesperson Deborah Klenotic.

» READ MORE: The entire state of New Jersey is under a drought watch

No end to New Jersey’s watch is imminent, said state Department of Environmental Protection spokesperson Larry Hajna. Any determination would be made based on a variety of indicators, including reservoir levels and water demands.

“While this week’s rainfall certainly helps,” he said, “we really need a number of rainfall events.”

Drought conditions have been scarce in Philly this century as rainfall generally has increased, which may well be related to the planet’s rising temperatures, as warmer air can hold more moisture.

Pennsylvania hasn’t declared a regionwide drought “emergency” for the city and the four neighboring counties in 20 years. The two most recent watches, in 2017 and 2011, were short-lived. The watch issued on Aug. 5, 2011, was followed by Irene’s record rains that pushed the monthly rain total in Philly to an incredible 19.11 inches.

» READ MORE: The region got quite a soaking on Tuesday, with a splash more on Wednesday

It is unclear whether this week’s rains were harbingers of a pattern change, but it is all but certain that they have given way to a splendid run of September weather likely to persist through the weekend.

Friday, Saturday, and Sunday are expected to be brilliantly sunny with highs in the mid-80s and comfortably cool nights in the 60s.

With no Irenes or other tropical threats on the horizon.