An outbreak of severe thunderstorms that could impact millions and snarl air travel across the country is expected to unfold today and tonight across a large portion of the Ohio Valley and Northeast.
Storms with torrential rain, damaging winds and hail will be ongoing this morning from the central Great Lakes into a portion of the Northeast, before another, possibly more significant round takes shape a bit farther south this afternoon and evening.
There is the potential for a large area to experience destructive wind gusts in excess of 70 mph, enough to bring down trees, damage structures and cause power outages that could last for days.
Major metropolitan areas, including Cleveland, Pittsburgh, Philadelphia, New York City, Albany and Hartford, are among those included in the enhanced risk zone for damaging winds through tonight.
An even larger area will still be at risk for severe weather, stretching from the mid-Mississippi Valley near St. Louis and Paducah all the way east into the mid-Atlantic and north to New England.
Similar to Wednesday night's damaging storms in the Upper Midwest, many areas will actually experience their worst weather after dark, especially along the I-95 corridor from Washington, D.C., to Boston.
In addition to the threat of powerful wind gusts, the setup appears ripe for a few storms to spawn tornadoes. This will especially be the case near the leading edge of a push of warm, humid air from northern Pennsylvania and southern New York into southern New England at night.
Hail as large as golf balls and rain heavy enough to cause rapid street flooding will also accompany many storms.
Driving along even major interstates could become difficult during storms, whether it be along I-71 from Louisville to Cleveland, I-80 from Akron to New York or I-84 from Scranton to Worcester.
By the end of the night, tens of thousands of lightning strikes will have occurred from the storms. Even if you are well ahead of or behind a storm, you still face the risk of being struck by lightning.
With such a multifaceted threat faced over a wide, highly-populated area, it is important that everyone from the Ohio Valley into the Northeast stay up-to-date with the latest on the location of the storms.
Dry and sunny conditions will continue in San Francisco for the official start to winter and the Christmas holiday.
Sunshine will return in full force for the weekend, the official start to winter, and Christmas in Los Angeles.
Big changes are on the way for parts of the Western and Central states late this week and into this weekend.
Similar to the days prior to Thanksgiving, the worst weather will focus on the days prior to Christmas as millions of travelers take to the roads and skies in the U.S. and southern Canada.
Warm air is forecast to surge into much of the eastern half of the nation by the weekend and will be accompanied by heavy rain and flooding risk in some locations.
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International Falls, MN (1989)
Low of -34 + high of -21. Wind chill between 60 + 70 below.
Lander, WY (1924)
Bar. pressure 31.29" 1060 mb.
Black Hills, SD (1964)
Chinook: temp. rise 0 degrees to 50 degrees.