The National Weather Service more than doubled its active heat alert count in the past 24 hours, from 43 to 89, as the heat dome driving dangerous conditions across the Plains and Southwest pushed into new territory across the Midwest and Southeast.
Alerts now stretch across 21 states — Arkansas, California, Colorado, Florida, Iowa, Idaho, Illinois, Kansas, Kentucky, Minnesota, Missouri, Montana, North Dakota, Nebraska, Nevada, Oklahoma, South Dakota, Texas, Utah, Wisconsin and Wyoming. That’s up from 13 states Sunday, with Arkansas, Florida, Illinois, Kentucky, Minnesota, Missouri, North Dakota, South Dakota, Utah and Wisconsin all added to the alert map as the heat pushes east and north. New Mexico and Washington, both under advisories a day earlier, are no longer listed.
The most severe conditions are centered on Kansas, where Barber County is under both an Extreme Heat Warning and a Heat Advisory simultaneously. The Weather Service says heat index values there could reach 112 this afternoon and evening before the Extreme Heat Warning expires at 8 p.m. CDT, with a Heat Advisory taking over through 8 p.m. Monday as heat index values run as high as 110. Elsewhere in central and south-central Kansas, forecasters are tracking heat index readings of 108 to 109 through Tuesday evening.
The geographic spread illustrates how far this heat dome now extends. In Minnesota and North Dakota, advisories cover a belt of counties from the Red River Valley — Grand Forks, Cass, Richland — east through Otter Tail and Becker counties. In Nebraska, the alert zone runs from Boone and Platte counties in the east-central part of the state down through Lancaster and Saline counties near the Kansas border. Kansas alone accounts for dozens of the affected counties, from Barber and Comanche in the south to Cass and Saline further north.
The National Weather Service’s standard guidance remains in effect across the affected region: drink plenty of fluids, stay in air-conditioned spaces, avoid direct sun exposure, and check on relatives and neighbors, particularly the elderly. Officials are also warning against leaving children or pets in parked vehicles, and urging anyone working or exercising outdoors to take extra precautions and wear lightweight, loose-fitting clothing.
With advisories now extending into Wisconsin and Illinois and as far south as Florida, the heat is no longer confined to the Southwest and Plains corridor that defined the pattern earlier in the week. Forecasters have not indicated when the alert footprint will begin to contract, and additional counties could be added as the week continues.