'Otherworldly' Cold, Subzero Wind Chills To Hit PA: See The Timeline

EASTERN PA — The intense cold front will reach its peak overnight Friday into early Saturday morning, bringing dangerously low temperatures and subzero wind chills to the greataer Philadelphia area.

The wind chill is forecasted to dip as low as negative 5 for parts of the region overnight, with low remperatures around 11 degrees in the city and lower in the outlying suburbs, accoridng to forecasters.

Wind gusts of up to 30 miles an hour could hit the area Friday night, with sustained winds of over 20 miles an hour in some places, forecasters said.

When the polar vortex remains strong, frigid air can't escape the Arctic. That's been the case for much of the mild winter. But in recent days, AccuWeather says the vortex has weakened and stretched just enough to allow bitter-cold air to move southward across North America.

Arctic air will remain in place Saturday morning, according to weather officials. Winds will relax somewhat but remain breezy. The wind chill will remain under zero on Saturday, with a high only reaching 27 degrees.

The same blast of Arctic air will send temperaturs plummeting to what AccuWeather calls "otherworldly" temperatures across much of the east. Atop Mount Washington in New Hampshire, the temperature will be about negative 45, with a "real feel" of an unprecedented 100 degrees below zero.

"For comparison, the weather instrument on the Mars Curiosity rover regularly observes low temperatures around 100 degrees below zero," AccuWeather added.

Here's the forecast for the region through the weekend:

Friday

Mostly sunny, with a high near 29. Blustery, with a northwest wind 15 to 20 mph, with gusts as high as 30 mph.

Friday night

Mostly clear, with a low around 11. Wind chill values as low as -2. Blustery, with a northwest wind 15 to 20 mph, with gusts as high as 30 mph.

Saturday

Sunny, with a high near 27. Wind chill values as low as -1. Northwest wind 5 to 10 mph becoming southwest in the afternoon.

Saturday night

Increasing clouds, with a low around 24. South wind 10 to 15 mph.

Sunday

Partly sunny, with a high near 48. Breezy, with a southwest wind 15 to 20 mph.

Sunday night

Mostly cloudy, with a low around 35.