BETHLEHEM, Pa. — A reinforcing cold front has triggered a freeze watch in the Lehigh Valley from Thursday evening through Friday morning.
Sub-freezing temperatures between 26 degrees and 31 degrees are possible, the National Weather Service said, with the coldest temperatures expected in sheltered valleys.
The watch covers Sussex and Warren counties in New Jersey, along with Lehigh, Northampton, Carbon and Monroe counties in Pennsylvania.
The weather service said temperatures could be right around or just above freezing in the Allentown area, which could kill crops and other sensitive vegetation.
It comes after four consecutive days of highs in the low 80s — a departure from normal of 7 to 10 degrees based on the time of year.
It’s expected to be our coldest night since the temperature dropped to 31 degrees on April 18.
‘A strong push of cold air’
The front will pass through the region today, and despite the afternoon sun, it will become increasingly breezy, the weather service said in its latest forecast discussion.
“For most areas, northwest winds may gust up to 25-30 mph this afternoon," the forecast said. "As a result, temperatures today will be noticeably cooler than recent days, with highs only topping out in the mid 60s to low 70s.”
A secondary, or reinforcing, cold front will then punch through, bringing a second wave of cooler, drier air that will intensify the temperature swing.
“It’s behind this secondary front where a strong push of cold air will advect into the region,” the forecast discussion said, highlighting low temperatures that will bottom out mainly in the 40s tonight into Thursday, and in the 30s Thursday night into Friday.
Thursday will be the coolest day of the season so far, the weather service said, with high temperatures struggling to climb above the 60-degree mark into the afternoon.
“Given the clear skies and nearly calm winds, widespread frost development appears increasingly likely" overnight, the discussion said.
Coastal storm to follow?
Forecasters also are keeping an eye on a “potentially significant coastal storm” that could impact the region Sunday and into early next week.
While the evolution of the storm still is in question, the weather service said its “growing increasingly concerned about the potential impacts,” particularly along and near the coast.
A number of outcomes remain on the table, with a weaker and/or farther-south solution translating to less severe impacts and lower chances of rain for our region.
A stronger and/or farther-north placement of the storm would translate to greater and potentially much more severe impacts to the area, including potential coastal flooding, significant beach erosion and strong to damaging winds near the coast and in the coastal plain.
