Severe thunderstorms may threaten midwestern, northeastern US to end the week

By Alex Sosnowski, AccuWeather senior meteorologist

February 21,2017, 2:52:59PM,EST

 The risk for severe thunderstorms will ramp up across the Ohio Valley states and lower Great Lakes region to end the week.

The severe weather potential will occur at the tail of record-challenging warmth. The same storm will bring blizzard conditions to part of the central United States late this week.

The thunderstorms will mark the leading edge of colder air that will sweep southeastward from Canada and slash temperatures by 20 to 30 degrees Fahrenheit during the last weekend of February.
"The strongest storms will produce powerful wind gusts, heavy rain and hail," according to AccuWeather Storm Warning Meteorologist Brian Knopick.

The storms have the potential to cause travel disruptions, including airline delays, in the Midwest from Detroit to Indianapolis, Indiana; Cleveland and Cincinnati, Ohio; Nashville, Tennessee; and Pittsburgh.
Heavy, gusty thunderstorms could extend as far south as the northern parts of Mississippi and Alabama.
Flash and urban flooding are the greatest threats, but winds can be high enough to topple trees and cause sporadic power outages in the strongest storms.
"It is possible that a couple of the strongest storms produce an isolated, brief tornado as well," Knopick said.
The first storms are likely to erupt from parts of the Lower Peninsula of Michigan to part of the lower Ohio Valley during Friday afternoon.
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The storms will then progress eastward across part of the lower Great Lakes region and the upper Ohio Valley during Friday night.
Thunderstorms may survive or re-fire in parts of the mid-Atlantic and New England on Saturday.

At the very least, part of the Northeast will be hit with downpours and some thunder and lightning at a time when outdoor activities typically ramp up.
"The weather for the outdoor NHL Stadium Series game between the Penguins and Flyers at Heinz Field in Pittsburgh will be windy and turning cooler," according to AccuWeather Meteorologist Brian Lada.
While steady rain and thunderstorms should move off in time for the game, there will be the risk of passing showers as temperatures hover in the 40s.
Even where storms weaken moving into parts of the upper Great Lakes, New England and neighboring Canada, rain could be heavy enough, when combined with melting snow to raise the risk of flooding.
The sweep of cold air will end the severe weather threat for the time being over the Midwest and Northeast. However, the press of cold air could pave the way for wintry precipitation in parts of the Ohio Valley and Northeast early next week.