BETHLEHEM, Pa. — Lehigh and Northampton counties are again under a flood watch, this time from 3 p.m. Wednesday through 3 a.m. Thursday.
The National Weather Service expanded the flood watch area just before noon to include the Lehigh Valley, saying flash flooding caused by excessive rainfall continues to be possible.
Intense storms soaked the region on Monday, dropping more than 5 inches of rain in some areas in just a few hours.
Rounds of showers and thunderstorms are expected later Wednesday afternoon and evening.
“Storms will be capable of dropping a quick 1 to 2 inches of rainfall within a 1-to-3-hour period, leading to flash flooding,” the watch said.
It said isolated amounts of 2 to 4 inches will be possible.
Tropical air mass remains locked in
It comes as a very warm and humid air mass continues to blanket the region.
The weather service said a frontal boundary will remain stalled across the northern portion of the area today before lifting north of the area as a warm front on Thursday, when the heat and humidity will peak.
The Lehigh Valley is under a heat advisory Thursday for heat indices reaching 100 degrees.
A cold front passing through the region Thursday night into Friday could bring slight relief, forecasters said.
“Temperatures and especially dewpoints/humidity will be on the decline for Friday, with dewpoints finally dropping into the 60s for northern areas,” the latest forecast discussion said.
It said Friday night will be “quite pleasant by mid-July standards, with dewpoints continuing to fall under a light northerly breeze.”
