BETHLEHEM, Pa. — The Lehigh Valley is about to experience “a decidedly early November-like day,” according to the National Weather Service.
That includes the coolest air of the season thus far, followed by a frost advisory in effect from midnight until 9 a.m. Friday morning.
The advisory covers Lehigh, Northampton, Berks, Bucks, Carbon and Monroe counties. It also covers parts of Chester and Montgomery counties.
Overnight temperatures ranging from 34 to 37 degrees will result in areas of frost formation, the advisory states.
Frost could harm sensitive outdoor vegetation, and sensitive outdoor plants may be killed if left uncovered.
The Lehigh Valley hasn’t seen overnight lows in the 30s since April 27, when the daytime high was 57 and the overnight low dropped to 35.
How we’ll get there
EPAWA meteorologist Bobby Martrich said a trough settling over the region will let temperatures be quite cool Thursday.
Martrich said 58 to 63 degrees will be the temperature spread across the region — some of the coolest we’ve seen so far this season.
Temperatures overall will be 5-10 degrees below normal, and areas north of Interstate 78 likely will fail to make it out of the 50s.
“There will be a noticeable 10-15 mph northwest breeze throughout the day, with some gusts near 20-25 mph at times,” the weather service said in its latest forecast discussion.
“The breeze during the daytime will gradually lessen into the night, eventually becoming 5 mph or less in most areas,” the discussion said.
The clear skies will promote traditional cooling, and offer good conditions for the potential viewing of the aurora.
Even cooler temperatures ahead?
“I think we’re going to have even cooler temperatures as we get into early next week,” Martrich said.
The weather service said it will be a very dry and cool air mass arriving, with temperatures “expected to be below climatology through the rest of the long-term forecast period.”
“This could entail a more widespread threat of frost, along with daytime highs struggling to break 60 by midweek,” the forecast discussion said.
