Extreme Heat Fueling Severe Storms in the Midwest, Power Outage Concerns in the East

Blazing heat and high humidity are making for an explosive combination from the Plains all the way to the Eastern Seaboard. Extremely hot, unstable air is helping fuel dangerous wind storms in the western Great Lakes tonight. Meanwhile, residents of the big eastern urban centers are preparing for killer heat over the weekend.

A cluster of severe storms has been racing across parts of Minnesota and northern Wisconsin Friday evening (see animation above). The storms are feeding on abnormally high humidity and temperatures to the south and should continue to roll into Lower Michigan early Saturday morning. Reports indicate widespread winds of 60-80 mph (100-130 kph) have knocked down numerous trees and powerlines, resulting in thousands of power outages.

The same hot air mass has built into the Eastern Seaboard for the upcoming weekend. Temperatures from Washington D.C. through Philadelphia, New York City, and Boston will reach well into the 90s if not the lower 100s (upper 30s deg C). The record-threatening heat combined with high humidity will result in dangerous heat index values of 105 to 115 deg F. In this range, heat exhaustion is likely even with only short-duration outdoor activity. Prolonged exposure or physical activity outside can result in heat stroke, a potentially deadly condition. Heat-related illnesses account for more deaths annually than any other weather phenomena. This dangerous heat spell is made worse by the fact that overnight temperatures will not fall much, especially in the cities. That means very little opportunity for relief from the heat, increasing the risk of heat-related illness, especially among the elderly. Officials in all the major cities have opened hundreds of public cooling shelters and are encouraging those without access to air conditions to take advantage.