BETHLEHEM, Pa. — After a period of quiet post-Christmas weather, things could get slick in the Lehigh Valley heading into the weekend.
Temperatures will drop below freezing across the area late Friday night and early Saturday, likely setting the stage for a period of freezing rain, according to the National Weather Service.
Icy spots can be expected on roads and sidewalks as precipitation moves through the region after 1 a.m. Saturday, the weather service said in its latest forecast discussion.
Good Thursday Morning Everyone! After the day time tomorrow, the weather pattern is going to get active again, so bear with us, as there is a lot to talk about this morning! (1/5)
— NWS Mount Holly (@NWS_MountHolly) December 26, 2024
As always, you can find the latest detailed forecast for your location at https://t.co/LgidMZaLEV pic.twitter.com/55fo9Rp1yk
Areas along and north of the Pennsylvania Turnpike/Interstate 95 corridors, including the Lehigh Valley, saw a “modest increase in the chance for freezing rain” in the latest updates.
By 3:14 p.m., NWS Mount Holly issued a winter weather advisory for the Lehigh Valley and surrounding areas, in effect from 7 p.m. Friday to 9 a.m. Saturday. The advisory warns of "a light glaze" from freezing rain, which could create "very slippery sidewalks," as well as roads and bridges.
"If you are going outside, watch your first few steps taken on stairs, sidewalks, and driveways," the advisory says.
The weather service said overnight temperatures at the surface will be in the upper 20s to mid-30s.
“The big question remains if the precipitation will move in early enough for freezing rain to occur,” the forecast discussion said.
The chance for freezing rain is 30 to 50%, but could be all rain if precipitation holds off until after sunrise Saturday, the NWS said. If that were the case, most areas should see rain.
Cold air damming, again
The same setup that influenced our weather a few weeks ago could again play a role, according to EPAWA meteorologist Bobby Martrich.
Martrich said cold air damming, which takes place when a low-level cold air mass is trapped topographically, could result in that period of freezing rain early Saturday.
Martrich said the pattern will have warm air overriding colder air at the surface.
“So warmer air aloft, and when these two meet, you’re going to have some icing,” Martrich said in his latest video update.
“Not a lot, because this is not heavy precipitation as far as the icing is concerned, but you might have a little bit of that overnight.”
After that, warm air will push forecast highs Saturday into the low 40s, with daytime highs soaring into the mid-50s on Sunday.
A warm, wet pattern to follow
The weather service said chances for any wintry precipitation “will remain very unlikely with temperatures in the 50s to lower 60s Sunday and overnight lows mostly in the 40s.”
It also may be warm enough for embedded thunderstorms Sunday night just ahead of a cold front expected to sweep through Monday morning.
“This would be very unusual, both in terms of time of day and time of the year,” the forecast discussion said.
Current outlooks suggest the general pattern looks to remain wet through New Year’s Eve into New Year’s Day.
