United States

Locally damaging thunderstorms will continue to fire on the rim of record heat over the middle of the nation, including the northern Plains into the end of the week.

While metropolitan areas such as Minneapolis and Rapid City can be hit by the storms, the risk of strong to severe thunderstorms will encompass hundreds of square miles through Friday.

As temperatures climb to and past 100 degrees over the central Plains and Ohio Valley into Friday, powerful thunderstorms will continue to roll along the edge of the heat, riding a strong, clockwise flow of air.

Storms from parts of the Dakotas to parts of Iowa, Nebraska, Minnesota and Wisconsin can pack a punch with damaging wind gusts, large hail and frequent lightning strikes.

A couple of the strongest storms over the northern High Plains could also produce a brief tornado.

In the few places where the storms repeat over several hours, known as "training," there can be incidents of flash and urban flooding.

While much of the corn belt needs rain in any form, a several-day soaking event would be better than all at once. However, most of the driest areas of the corn belt will not get enough rain of any sort over the next several days to make much of a difference, according to agricultural meteorologists at AccuWeather.com.

A significant percentage of the corn from southern Iowa, Kansas and Missouri to Ohio has had too much heat and drought already and will likely result in heavy production losses later in the season.

Abnormally dry and drought areas continue to expand and worsen as of July 3, 2012.

The core of the intense heat on top of the existing drought has hit during the prime pollination period of the crop.

Temperatures will back off over much of the region beginning this weekend, but the damage has already been done.

Powerful storms also blasted across West Virginia Thursday afternoon, including some areas that were slammed by massive power outages nearly a week ago.