National Weather Service: Potential for 'unusually significant or widespread' flooding this week

BETHLEHEM, Pa. — The Lehigh Valley and surrounding areas could see flooding caused by excessive rainfall this week, the National Weather Service said.

A flood watch is in effect for Lehigh and Northampton counties and much of the mid-Atlantic region.

It comes after record rainfall in December and a storm over the weekend that dropped up to 9 inches of snow in some parts of the area.

With expected rains and the predicted snow melt, Lehigh and Northampton counties are among 13 Pennsylvania counties and others in New Jersey and Delaware under such a warning.

“Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations," the watch states.

"Area creeks and streams are running high and could flood with more heavy rain.

MORE: Emergency crews getting ready for risk of flooding after snowstorm

“Forecast rainfall for Tuesday into Wednesday has widespread total amounts of 2 to 3 inches with localized amounts of 4 inches possible."

Timing

The weather service said the heaviest rain is expected to fall Tuesday night, along with a period of strong to damaging winds possible across the region.

But as the storm arrives, some areas north of the Lehigh Valley could see some wintry precipitation, EPAWA meteorologist Bobby Martrich said in his latest video forecast.

Martrich said the snow should be confined to central Pennsylvania, sweeping north up along the Pennsylvania/New York border.

The rain then will become heavy at times later Tuesday afternoon and especially Tuesday night, tapering off to showers early Wednesday morning.

Impacts

Martrich said there’s the potential for a squall line with some very gusty winds moving through, but he was more focused on the potential for a “dire flooding situation” to unfold.

“I don’t use those words very often because I’m not one to use hype-type words,” he said. “But you have to understand in the month of December we had three major systems that produced 2 inches or more on three different occasions, most recently Dec. 27-28.

“Then we had the system this weekend that gave us rain and snow, and some areas still have a lot of that snow on the ground.”

Martrich said the snow melt added to the heavy rainfall is concerning.

“It’s not a good situation with the already saturated ground, and then we’re going to get all this rain on top of that,” he said.

As of 6 p.m. Sunday, the Middle Atlantic River Forecast Center was forecasting flooding at 19 river forecast locations across the mid-Atlantic region.

A storm arriving late week could bring yet another round of heavy precipitation to the area.