Flood watch out again in southeastern Pennsylvania ahead of expected storms

Here we go again.

A National Weather Service-issued flood watch is in effect for all of southeastern Pennsylvania for Tuesday from noon to midnight. The watch also applies to New Castle County, Delaware, and much of northwest New Jersey

The same region hit by downpours recently looks primed to again be in the target zone. Storms Monday into Tuesday helped boost rain totals and cut further into precipitation deficits for the year.  

A flood watch Monday turned into a thunderstorm watch, which turned into warnings into the night as storms crossed the region.

The newest watch reads in part: “Scattered showers and thunderstorms with locally heavy rain are expected across the watch area this afternoon and evening. Widespread rainfall amounts near 1 inch, with locally higher amounts near 3 inches occurred on Monday, saturating the ground. Rainfall amounts of 1-2 inches with localized amounts near 3 inches will be possible with the showers and thunderstorms today.”

In other words, the ground is saturated in many areas and another downpour might kick off localized flooding.

The threat appears to be highest in early afternoon, then tapers. Expect a high Tuesday near 80 degrees with fairly humid conditions.

Wednesday looks like a carbon copy, except that after dark a west-northwest flow is expected to take over and drier conditions should end the month. according to the forecast.

With the threat of rain off the table and sunny skies, expect highs in the mid-to-upper 80s the final two days of the month.

A Pennsylvania Department of Environmental Protection-issued drought watch remains in effect for the entire state, though plentiful rainfall in the southeast has cut into what was a significant precipitation deficit for 2023 through May.

Delaware, Chester and Berks counties bounced back over the weekend from the 26% to 50% below-normal category to the 11% to 25% category. Montgomery County bounced back on Monday.  

The southcentral counties from Fulton to Lancaster remain well within the 26% to 50% category.

At Philadelphia International Airport, the rainfall for June is up to 3.17 inches, a few tenths below normal. At Reading Regional Airport, the monthly total is 3.22 inches but that’s nearly an inch below normal. Plus, Lehigh Valley International Airport is at 3.63 inches for June, a couple of tenths below normal.

Normals are fairly high in June because of heavy summer rains in the latter years of last decade. Normal is calculated as the averages of the most recent three completed decades.

The county totals are courtesy of a division of the weather service that incorporates more stations, radar estimates and the watchful eye of a hydrologist. It presents a more accurate picture.

Some areas of southeastern Pennsylvania were hit hard on Monday and overnight, such as East Branch Brandywine Creek, 3.80 inches; Brandywine Creek at Chadds Ford, 3.52; Marshallton, 3.09; Thornton, 2.55; Brandywine Regional Airport, 2.41; Kennett Square 2.25; Saint Davids, 2.19; and Media, 2.18.

Source: Berkshire mont