United States

By Alex Sosnowski, Expert Senior Meteorologist

August 03, 2012; 8:26 PM

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Flickr image of a supercell thunderstrom by Topato.

There is the potential for a severe weather outbreak spanning through Sunday across the northern tier of the United States and neighboring Canada.

The outbreak includes the risk of strong straight-line winds, large hail and a few tornadoes.

An unusually potent disturbance for early August will swing from northwest to southeast across the northern Plains and adjacent Prairies in southern Canada during the latter part of this week to the Great Lakes, St. Lawrence Valley and central Appalachians spanning this weekend.

This feature is likely to produce both complexes of thunderstorms with high winds, hail and flash flooding on a regional level, as well as isolated intense thunderstorms capable of bringing a tornado to a few communities.

The feature, which resembles a storm system from the springtime, was rolling eastward into Saskatchewan early Friday morning.

Power outages, property damage and frequent lightning strikes can occur with some of the storms.

Timing

The risk area today be found in the eastern Dakotas, western and central Minnesota, southeastern Manitoba and part of northwestern Ontario.

The area from central Iowa to eastern Wisconsin, including Des Moines, Minneapolis and Madison, Wis., could be in the crosshairs of the nasty storms during Saturday.

Ominous storms could be in the vicinity of Chicago Saturday evening.

There is the potential for more of a squall line setup later this weekend around the central and eastern Great Lakes and Ohio Valley and into the central Appalachians.

Approximate timing for the severe storms from Indianapolis to Detroit, Toronto and Ottawa would be Saturday evening into early Sunday.

During Sunday, the storms would affect areas from Nashville to Cincinnati, Pittsburgh, Buffalo, Scranton, Albany and Montreal.

During Sunday evening into Monday, the storms would advance across the Appalachians into the I-95 zone, after a weekend of heat, humidity and spotty drenching storms.

People in the path of this potentially damaging and life-threatening storm system should keep up to date on the latest weather information.

Spotty and locally strong thunderstorms will fire ahead of this event in portions of the Plains, Midwest and the East.