BETHLEHEM, Pa. — A surge of Arctic air behind a cold front racing through the U.S. this week is expected to bring widespread, dangerous wind chills through much of the central U.S. and a potential flash freeze to the mid-Atlantic and Northeast, forecasters warn.
A major winter storm is forming on the front, and is expected to bring heavy snow and high winds, creating blizzard conditions for parts of the Plains into the Great Lakes.
- A major winter storm being described as an "impactful extratropical cyclone" is racing across the country
- It will send temperatures plummeting in the Lehigh Valley
- A flash freeze and power outages are a concern for the region
Then it will roll into the Lehigh Valley and the rest of the region, with the National Weather Service already warning of “isolated instances of tree damage and power outages” expected on Thursday and Friday.
The storm is being described as an “impactful extratropical cyclone” — the type that has cold air at its core and derives its energy from cold and warm air masses interacting. They always have one or more fronts connected to them, according to the weather service, and can occur over land or the ocean.
The bigger issue at the heart of the storm is the winds, which can be as weak as a tropical depression or as strong as a hurricane.
Temperatures in the Lehigh Valley are expected to plummet, creating flash freeze concerns Friday as heavy rain potentially turns to wintry precipitation on the back end.
“Friday is going to be rough. Power outages most notably. Heavy rain to sleet/graupel to snow (short time) with rapid temp drop in just 1 hour 20-25 degrees,” EPAWA meteorologist Bobby Martrich tweeted Monday, saying even with the back end snow possibility, “impact lies elsewhere.”
“Wind should be crazy with the front ... to get that kind of rapid temp drop, it has to be,” he added.
Here’s how forecasters are breaking down the storm:
- Some mix of snow, rain or freezing rain possible at the precipitation onset early Thursday morning, but overall impacts at this time are not expected to be significant. The weather service says the most likely area for this to occur would be north and west of the I-95 corridor.
- Rain will follow, with the overnight Thursday-Friday morning period expected to see some heavier rain rates and potential for localized flooding.
- The very potent cold front is expected to pass through Friday afternoon, bringing with it the possibility for strong winds and limited instability, which could bring thunder.
One of the coldest cold fronts we’ve ever seen from the standpoint of cold pic.twitter.com/rxAkFB6FUy
— John Homenuk (@jhomenuk) December 20, 2022
- Behind the front, dry air will rush in and likely put an end to the precipitation.
Beyond the winds, the cold will be the biggest story and the Lehigh Valley will have its coldest Christmas in decades.
The coldest high temperature on record in Allentown for Christmas Day is 8 degrees, and the coldest low temperature is minus -2, the weather service told LehighValleyNews.com late Monday.
“Currently, our temperature forecasts are solidly above these values. It doesn’t look like we’ll be threatening records at this point, though it certainly will be chilly.”
