BETHLEHEM, Pa. — If you’ve been enjoying the fall-like temperatures in the Lehigh Valley, don’t shoot the messenger conveying the short-term forecast.
Just blame Francine.
Tropical Storm Francine is expected to bring heavy rainfall and the risk of considerable flash and urban flooding across parts of Louisiana, Mississippi, Alabama and the Florida Panhandle through Thursday night, according to the National Hurricane Center.
And while the storm and its remnants will not move this way, it will play a role in the Lehigh Valley’s weather pattern for the next few days.
Tropical Storm #Francine Advisory 15: Francine Moving Farther Inland Over Southeastern Louisiana. Heavy Rainfall Spreading Across Mississippi, Alabama, and the Florida Panhandle. https://t.co/tW4KeGe9uJ
— National Hurricane Center (@NHC_Atlantic) September 12, 2024
That’s because high pressure will be situated to our north and east, along with an upper-level ridge building over the Great Lakes combined with a Rex Block — a blocking pattern where there is an upper-level high directly north of a closed low.
“This is going to set up a roadblock,” EPAWA meteorologist Bobby Martrich said in his Wednesday video update.
It means what’s left of Francine will start to crawl north, but eventually won't be able to go any farther.
"The remnant low of that hurricane is sitting out here [in the Tennessee Valley] and it cannot go through that high," Martrich said.
"That is not how physics works. High pressure guides low pressure and not the other way around."
Martrich reiterated that messaging in his Thursday update.
What it means for our temps
The aforementioned pattern will result in mainly clear skies, along with some occasional high clouds from Francine fanning in from south to north, the National Weather Service said.
Highs generally will be in the upper 70s to mid 80s across the region, with lows ranging from the mid 50s to low 60s.
"Humidity also is expected to rise some through the period but should remain rather comfortable," the NWS forecast discussion said.
Martrich said temperatures will be "nudging up a little bit each day" and it will get progressively warmer.
"I think the peak heating day of this entire ridging episode will be on Saturday," he said.
"Saturday looks like the day that's going to be the warmest of the entire period."
Highs in the Lehigh Valley are expected to push into the upper 80s, and the pattern will continue to yield dry conditions and above-normal temperatures through Sunday.
The pattern does appear to break down early next week, the weather service said, which could finally result in much needed precipitation returning to the region.
"Global guidance indicate that there is potential for the development of a tropical disturbance off the Southeast U.S. eventually lifting northward by midweek," the forecast discussion said. "Will have to monitor this closely as weather features following blocking patterns are often difficult to predict."
