The US National Weather Service said south-central Texas is likely to encounter continued widespread life-threatening flash and urban flooding.
The region is also likely to see catastrophic river flooding and rapid water level increases in small streams, arroyos, and typically dry washes, the agency said.
Meanwhile, the Great Basin and Southwest are forecast to experience persistent monsoon showers, with flash flooding expected in Arizona.
In Texas, the NWS issued a flash flood warning early Friday for Junction, Rocksprings and Uvalde, with parts of Rocksprings also covered under a tornado warning watch.
Meanwhile, a flood warning was raised for parts of Uvalde, along with Pearsall, Carrizo Springs, Eagle Pass, Karnes City, Kerrville, Victoria, San Antonio, New Braunfels, Georgetown, and Burnet. American Electric Power's (AEP) Texas unit is among the primary service providers in these places.
A flash flood warning was also raised for Arizona's Phoenix, Globe, Payson, and Casa Grande, largely served by Pinnacle West Capital (PNW) unit Arizona Public Service Company.
Flood warnings were also raised for certain areas of Illinois, Iowa, and Louisiana.
The NWS issued a red flag warning early Friday in Idaho's Bonners Fry, Sandpoint, Coeur D Alene, Shoup, Salmon, Leadore, Challis, Mackay, Sun Valley, Hailey, Island Park, Arco, Dubois, Palisades, Pocatello, Soda Springs, Montpelier, Preston, Burley, Malad City, and Twin Falls.
PacifiCorp's Rocky Mountain Power, Avista (AVA) unit Avista Utilities, and Idacorp's (IDA) Idaho Power are the major electricity providers in the state.
A similar warning was raised for Washington's Winthrop, Omak, Wenatchee, Chelan, Coulee Dam, Spokane, Rosalia, Ritzville, Pullman, Republic, and Colville, primarily served by PacifiCorp's Pacific Power and Avista Utilities.
Also covered under a red flag warning watch were Chemult, Chiloquin, Bly, Klamath Falls, Lakeview, Paisley, and Silver Lake in Oregon; and Tulelake, Alturas, Likely, and Canby in California. These places largely fall under the service area of Pacific Power.
The NWS issued an extreme heat warning for Minnesota's Minneapolis, St. Paul, and areas near Red Wing, where Xcel Energy (XEL) is the prominent electricity provider.