A late-season heat event is holding across a wide stretch of the country, and forecasters have put Extreme Heat Warnings in place from the Arizona deserts to northwest Arkansas. The western warnings run through Thursday evening in most areas and through Friday evening in the Imperial Valley, which means the exposure is measured in days rather than hours.
The specific numbers explain why the alerts carry the strongest heat label the National Weather Service uses. In the Colorado River Valley and Death Valley, forecasters projected high temperatures of 112 to 116 degrees, with 105 to 110 in the Las Vegas Valley, Moapa Valley and Pahrump Valley. In Imperial County and the Imperial Valley, afternoon temperatures of 106 to 112 were expected. The Phoenix metropolitan area was forecast to reach 105 to 109, and the Yuma area 107 to 110. Across northwest and west central Arkansas and eastern Oklahoma, the NWS Tulsa office warned of heat index values above 110.
