Flash flood remains effect for entire Philly region on Thursday; heavy rain expected into the evening

Nearly 3 inches of rain, over an inch of that between 2 and 3 p.m., was measured at Atlantic City Airport Thursday, and with more downpours expected the National Weather Service’s flood watch for the entire region remains in effect until midnight.

Flood advisories were up late in the day through the hearts of Bucks Chester, and Montgomery Cojnties, and parts of Camden, Gloucester, Cumberland, and Salem Counties, but no measurable rain had fallen in Philadelphia since the early-morning hours.

Still the flood watch covers all of southeastern Pennsylvania, all of Delaware, and most of New Jersey.

It remains unclear precisely which areas the heaviest rains will target as computer models were sloshing all over the place. One thing they do agree on is that the atmosphere remains primed.

Rainfall of up to three inches is possible, with isolated higher amounts, said Alex Staarmann, a meteorologist with the weather service office in Mount Holly. “The models have trended wetter in the last day or so,” he said.

» READ MORE: Philly received 25% of its total 2020 precipitation in just one very rainy week

With a cold front approaching, the weather service says, a “plume of rich tropical moisture” to the south will lift northward. The atmosphere will be moist enough to wring out one- and two-inch rains in a hurry, thus the flood watch.

Showers and possibly thunderstorms are expected throughout the day and well into the night.

The region has become quite well-acquainted with disruptive downpours.

Despite the recent run of dryness, rainfall is well above normal throughout the region over the last 90 days.

In July and August, more than 14 inches of rain was measured at Philadelphia International Airport, or 6-plus inches above normal. But 60 percent of that total fell on just two days, July 10 and Aug. 4.