BETHLEHEM, Pa. — The arrival of a slow-moving weather system will make for an unsettled weekend, forecasters say, with an excessive rainfall risk Sunday for the Lehigh Valley.
While the next two days won’t be a washout, showers and thunderstorms will increase as the system arrives from the west, according to the National Weather Service.
In addition to heavy rain Sunday, the Storm Prediction Center also has the area at a marginal risk (1 out of 5) for severe weather.
Here’s what to expect as the weekend plays out:
Saturday
A southerly flow is expected to result in a humid air mass as dew points increase into the upper 60s to low 70s Saturday, forecasters say.
And while Hurricane Ernesto churns well offshore of the U.S. East Coast, it will act like a roadblock and slow the system arriving in our region.
Ernesto is “the stronger of the two entities,” EPAWA meteorologist Bobby Martrich said in his latest video update.
“That will slow up the flow [of our storm] a little bit, and that means it’s going to take its time moving through,” Martrich said, emphasizing the effects could last through Monday.
Locally heavy rain could occur in some areas Saturday as scattered showers and storms move through, especially in the evening hours.
Sunday
“I think Sunday is the better of the two days, as far as the concentration of precipitation,” Martrich said.
He highlighted that anyone with outdoor plans trying to dodge the weather will have better luck during the front half of the weekend.
As we go through the day, showers and storms are expected to increase — especially in the afternoon and evening.
“The available moisture, with precipitable water values around 2 inches, will once again lead to potentially locally heavy rain,” the weather service said in its latest forecast discussion.
A flash flooding risk is likely Sunday afternoon and evening from the urban Interstate 95 corridor to the north and west, with a slight risk for excessive rainfall leading to flash flooding.
An isolated severe thunderstorm risk also will exist, with strong winds as the main threat.
Some showers and thunderstorms also are likely on Monday before conditions improve, the weather service said.
That includes it becoming "noticeably cooler and less humid," with sunny skies and highs in the mid to upper 70s on Tuesday.
