Polar Vortex Brings Chance Of Snow To PA: See Latest Forecast

Blasts of Arctic air headed south by the polar vortex will hit eastern Pennsylvania over the coming days, causing temperatures to plummet and setting the stage for potential snow on Friday, forecasters said.

While the high could reach 40 degrees on Thursday, the Arctic air will steadily drop temperatures overnight into the teens.

Snow is likely to arrive by Friday afternoon, though forecasters are confident there will not be significant accumulation. Nearly all of southeastern Pennsylvania is expected to receive at least a dusting and perhaps slightly more, but totals will be less than an inch.

"Confidence is high this will not be a significant snow maker," the National Weather Service's Mt. Holly, New Jersey branch said.

The storm could cause travel delays and some cancellations, forecasters warn.

Meanwhile, the frigid air is likely just beginning. Forecasters expect a "triple whammy" from the polar vortex, meaning it could send successive blasts of cold air over the coming weeks.

"The outbreak this week will be the first of probably three such rounds with it. Another cold blast is likely next week and a third the week after that," Accuweather Meteorologist Paul Pastelok said. "The waves of Arctic air will lead to significant surges in energy demands."

For the coming week at least, low temperatures will remain mostly in the 20s, while dipping into the teens on a few nights. Wind chills could be significantly lower, making it feel up to 20 to 25 degrees colder than it actually is, Accuweather said.

The vortex is caused by an atmospheric disruption high in the Arctic, which causes changes in the stratosphere and shifts in how air flows. The exact causes of these atmospheric disturbances remain unclear and are under study by scientists. However, it is extremely unusual for a vortex to develop this early in the year.

Here's the full forecast for the coming week, according to the National Weather Service:

Thursday
Mostly cloudy, then gradually becoming sunny, with a high near 40. Northwest wind 10 to 15 mph, with gusts as high as 25 mph.

Thursday Night
Mostly clear, with a low around 20. Northwest wind 5 to 10 mph becoming northeast after midnight. Winds could gust as high as 20 mph.

Friday
A chance of snow after 1 p.m. Mostly cloudy, with a high near 32. Calm wind becoming east around 5 mph. Chance of precipitation is 30 percent. New snow accumulation of less than a half inch possible.

Friday Night
A chance of snow before 10 p.m., then a chance of snow and freezing rain. Mostly cloudy, with a low around 27. Calm wind. Chance of precipitation is 30 percent. New snow accumulation of less than a half inch possible.

Saturday
Partly sunny, with a high near 41. Calm wind becoming west around 5 mph in the afternoon.

Saturday Night
Partly cloudy, with a low around 28.

Sunday
Partly sunny, with a high near 42.

Sunday Night
Mostly cloudy, with a low around 25.

Monday
Mostly sunny, with a high near 32.

Monday Night
Partly cloudy, with a low around 19.

Tuesday
Mostly sunny, with a high near 37.

Tuesday Night
Mostly cloudy, with a low around 29.

Wednesday
Partly sunny, with a high near 44.