The US National Weather Service said it expected the Pacific Northwest, Rockies regions to experience continued wildfires and poor air quality, with similar conditions likely to spread to the Plains.
The northern Plains and upper Midwest regions could potentially face severe thunderstorms along a frontal boundary on Monday, while another weather boundary may bring showers and thunderstorms to the East seaboard, with some areas receiving heavy rain, the agency said.
In Alaska, winds and rainfall are expected due to a strong Bering Sea storm.
The NWS early Monday issued a red flag warning for Wyoming's Pinedale, Big Piney, Kemmerer, Evanston, Rocksprings, Rawlins, Sheridan, Buffalo, Douglas, Garrett, Medicine Bow, Elk Mountain, Saratoga, Baggs, Bill, Glenrock, Lance Creek, Glendo, Lusk, Torrington, Wheatland, Chugwater, Pine Bluffs, Newcastle, and Cheyenne. Wyoming mostly falls under the service area of PacifiCorp's Rocky Mountain Power.
A similar warning was raised for Nebraska's Harrison, Chadron, Alliance, Scottsbluff, Bridgeport, Harrisburg, Kimball, Sidney, Hyannis, Arthur, Ogallala, Rushville, and Chappell. A major part of the state is covered under the service area of regional transmission organization Southwest Power Pool, with Midcontinent ISO also serving some areas.
Also placed under a red flag warning were Beulah, Dickinson, Bismarck, Bowman, and Elgin in North Dakota, where Xcel Energy (XEL), MDU Resources (MDU) unit Montana-Dakota Utilities, and Otter Tail (OTTR) subsidiary Otter Tail Power are the major electric utility service providers.
Affected areas in South Dakota include Buffalo, Lemmon, Faith, Dupree, Belle Fourche, Sturgis, Spearfish, Rapid City, Hermosa, Wall, Philip, Pierre, Wall, Kadoka, Hot Springs, Edgemont, Pine Ridge, Martin, Mobridge, and Murdo. Xcel Energy, NorthWestern Energy (NWE), Montana-Dakota Utilities, Otter Tail Power, and Black Hills (BKH) subsidiary Black Hills Energy are among the major electric utility service providers operating in South Dakota.
In Montana, a red flag warning was raised for Cut Bank, Great Falls, Helena, Bozeman, Havre, Livingstone, Billings, Red Lodge, Miles City, Harlem, Conrad, Choteau, Fort Benton, Stanford, Lewiston, Boulder, Harlowtown, Roundup, Ekalaka, and Broadus. MDU Resources (MDU) unit Montana-Dakota Utilities and Northwestern Energy (NWE) are the major service providers in the state.
The NWS also issued red flag warnings for Oregon's Albany, Eugene, Cottage Grove, Cave Junction, Grants Pass, Crater Lake, Shady Cove, Ashland, Medford, primarily served by PacifiCorp's Pacific Power; and Cortez, Durango, and Nucla in Colorado, where Xcel Energy and Black Hills Energy are the primary electricity service providers.
In Utah, a red flag warning was issued for Duchesne, Price, Monticello, Bluff, Blanding, Green River, and parts of Capitol Reef National Park. Capitol Reef National Park was also placed under an extreme heat warning watch along with St George, Zion National Park, Escalante, and Moab. Rocky Mountain Power is the major service provider in the state.
The NWS also issued an extreme heat warning for Tonopah, Beatty, Las Vegas, and Caliente in Nevada, which falls under the service area of Berkshire Hathaway Energy unit NV Energy.
Affected areas in Arizona included: Parker, Kingman, Lake Havasu City, Yuma, Kingman, Bullhead City, Ajo, Gila Bend, Phoenix, Wickenburg, Dateland, Prescott, Payson, Globe, Casa Grande, Tucson, Nogales, Sierra Vista, Bisbee, Page, Oracle, Oro Valley, Benson, Safford, Sells, Green Valley, Page, and Grand Canyon Village.
Arizona is primarily served by Pinnacle West Capital (PNW) unit Arizona Public Service Company, and UNS Energy subsidiaries Unisource and Tucson Electric Power.
In California, an extreme heat warning was raised for Blythe, El Centro Imperial, Palm Springs, Twentynine Palms, Barstow, Baker, Death Valley, Campo, El Cajon, Mount Laguna, Julian, Borrego Springs, Ontario, Chino, San Bernardino, Hemet, Indio, Escondido, Hemet, Beaumont, Indio, Ridgecrest, Edwards AFB, and Frazier Park. PG&E (PCG) subsidiary Pacific Gas and Electric, Edison International's (EIX) Southern California Edison, and Sempra Energy (SRE) unit San Diego Gas & Electric are the major electricity service providers in these places.
The NWS issued flash flood warnings for certain parts of New York and Pennsylvania, while flood warnings were raised for small pockets of Texas and West Virginia.