Coldest air of winter to roar into central, eastern U.S.

Doyle Rice | USA TODAY

Show Caption Hide Caption Thursday's forecast: More snow heads to the Northeast The national weather forecast for Febuary 12th, 2015 calls for warmer temperatures in the pacific Northwest and continued snow showers in the Northeast.

Two punishing blasts of arctic air will bring the coldest temperatures of this winter to the eastern half of the USA just in time for Valentine's Day and Presidents' Day weekend.

High temperatures will make it only into the single digits and teens in major cities including Minneapolis, Chicago, Detroit, Pittsburgh and Boston by week's end, AccuWeather predicts. Overall, temperatures will be about 20 degrees below average for much of the central and eastern U.S.

While beleaguered New England will see two rounds of snow — on Thursday and Saturday — precipitation won't significantly impact most areas affected by the arctic blast.

By early Thursday, the first arctic plunge will move into the Midwest and Ohio Valley and will reach the East Coast late Thursday before making it all the way to the Gulf Coast and Florida by Friday, WeatherBug meteorologist Andrew Rosenthal said.

Howling winds will only add to the misery. "The combination of frigid air will not only be painful to endure for short periods of time outdoors but can bring life-threatening conditions for those not properly dressed," said AccuWeather meteorologist Brian Lada.

The bitter cold will reach down into the Deep South, where highs may reach only the 30s.

A second shot of even colder air will spread across the eastern U.S. by Sunday and into Monday. New York City may shiver through its coldest day in over two decades Sunday, said Weather Channel meteorologist Nick Wiltgen.

Daily record lows will be threatened both Sunday and Monday mornings in parts of the Northeast, Southeast and Great Lakes as the reinforcing cold blast plunges south, the Weather Channel said.

The air will get cold enough in central and northern Florida to bring the risk of damage to unprotected sensitive fruits and vegetables, AccuWeather predicts. Frost and freezes are possible as far south as Orlando by Monday morning, according to WeatherBell meteorologist Ryan Maue.

The cold stretch is likely to continue with varying levels of intensity into late February, the Weather Channel said. Meanwhile, most of the western half of the country will see unusually mild, potentially record warm temperatures this weekend, under mainly sunny skies.