Dangerous storms threaten to ruin outdoor plans and wreak havoc on the evening commute across the eastern Great Lakes and Northeast.
Very hot and muggy air will help to fuel the thunderstorms with temperatures climbing well into the 80s and 90s.
At least a couple of zones of nasty thunderstorms are expected to develop with the heating of the day encompassing areas from lower Michigan, Ohio, Pennsylvania and upstate New York to Virginia, the Delmarva, coastal New York, New Jersey and part of New England.
Some of the storms will become severe, providing the threat for damaging wind gusts and hail. In a couple of instances a tornado can be produced by the strongest storms.
Detroit, Cleveland, Buffalo, Pittsburgh, Philadelphia and perhaps New York City could all be in the path of the damaging storms.
The strongest storms can produce wind gusts to 65 mph which is more than enough to knock down tree limbs and power poles.
While damaging winds appear to be the biggest threat, there can be large hail and flash flooding.
If threatening weather approaches, be sure to have a secure indoor location to move to.
Heed any watches or warnings and as always, check back with the AccuWeather.com Severe Weather Center.
Strong thunderstorms will shift farther east Monday evening, bringing a damaging wind threat to Rochester, Burlington, and perhaps Montreal. However, as the night progresses, thunderstorms will lose their intensity thanks to loss of daytime heating.
A multi-vehicle accident involving 20 to 30 vehicles occurred amid snow showers and brutal cold, led to the shutdown of Interstate 78 in Lebanon County, Pennsylvania, Saturday morning.
The coldest air of the winter will plunge southward across much of the eastern United States and will feature single-digit and sub-zero temperatures in the Northeast during Valentine's Day weekend.
The dangerous cold gripping the eastern United States will set the stage for disruptive snow and ice to unfold from Tennessee and Georgia to Maine Presidents Day into Tuesday.
Voters heading out to the polls on Saturday, Feb. 20, can expect mild weather and dry conditions for the next step in the 2016 Presidential Election.
Heavy rain will raise the risk of flooding across more than a dozen states in the Southeast on Presidents Day to the East Coast on Tuesday.
Umbrellas will be needed on Valentine's Day as scattered showers overspread Germany.
Eastern US (1985)
Great Ohio Valley snowstorm whips snow into mountainous drifts and strands hundreds. In southwest Ohio 10 plows were stuck in the drifting snow and abandoned. Over a foot of snow in central and eastern Kentucky with 10 - 15 ft. drifts. Over 2 inches of snow in most of North Carolina.
Minneapolis, MN (1990)
String of 48 consecutive days with above normal temperatures broken.
Fairbanks, AK (1999)
-36 degrees; a record 19 straight days with lows less than -35 degrees.