BETHLEHEM, Pa. — By the end of October, most of the region will typically have seen frost.
“In fact, most of the region has, on one occasion or another, seen snow by month’s end,” the National Weather Service in Mount Holly said on X last week.
And while nothing like that is currently in the forecast, the Lehigh Valley this week could see its coldest overnight temperatures since late April.
Short-term outlooks suggest a cold front will make steady progress across the area Monday, according to the weather service, with northwesterly winds gusting up to 25 to 30 mph.
And if that’s not enough of a fall feeling, a reinforcing cold front is expected to cross the region Wednesday night.
“[The] coldest night of the season looks to be Thursday night, with many areas flirting with the upper 30s for the first time this season,” the latest NWS forecast discussion said.
The coldest spots in the Poconos could reach the freezing mark for the first time.
What’s driving the pattern?
“We’re certainly going to be cooler than we have been once we get past" Monday, EPAWA meteorologist Bobby Martrich said in his latest video update.
The region will see near-average temperatures, with a spread of 66 to 72 to kick off the week, before dropping a little bit lower Tuesday, Martrich said.
Colder spots in the Poconos have a good chance of at least some patchy frost on Tuesday night, according to the weather service.
“We’re certainly going to be cooler than we have been once we get past Monday."EPAWA meteorologist Bobby Martrich
Under mostly sunny skies, highs will rebound to readings almost identical to Tuesday on Wednesday, with widespread mid-60s to near 70.
“We keep kind of ticking down all the way ‘til we get to Thursday,” Martrich said.
But radiational cooling, or the cooling of the Earth’s surface, is expected to factor in Thursday night, as mostly clear skies should prevail.
Friday will see some recovery in temperatures, Martrich said, with mostly sunny skies expected straight through the end of the work week and into the weekend.
Lehigh Valley abnormally dry
As of Oct. 3, nearly 85% of the region was experiencing abnormally dry conditions, according to the weather service.
That includes roughly 30% in moderate drought, with much of the Lehigh Valley considered to be “abnormally dry.”
All of Lehigh County currently falls within that designation, with Northampton County likely to follow during the next update by the U.S. Drought Monitor on Thursday.
After a few showers crossed the region Sunday night, chances for measurable rain look very low over the next 1-2 weeks, the weather service said.
An outlook from the Climate Prediction Center valid through Oct. 20 is leaning below average (33-40%) for rain chances.
Allentown measured 3.54 inches below normal for precipitation in September, and is currently nearly an inch below average for October.
