Scorching heat again built up over the Plains and Upper Midwest early Monday as the furnace-like air that blistered California last week settled over the nation's midsection.
Numerous heat warnings were in place from Michigan to Oklahoma, with high temperatures expected to climb into the 90s or 100s, and sparking thunderstorms along its eastern edge.
Heat indices were also expected to reach triple digits in much of the eastern part of the country, except parts of New England.
The heat wave was keeping thousands huddled in their air-conditioned homes as many poor and homeless people sweat it out or head for cooling centers.
The combination of temperatures in the mid to upper 90s and high humidity threatened to make it feel like 100 degrees to 105 degrees in the Lower Peninsula.
In western Upper Michigan, highs ranging from 97 to 102 degrees combining with high humidity could make it feel as hot as 110 degrees to unprotected skin, forecasters said.
Highs Sunday reached only into the 80s statewide, but thunderstorms caused disruption and damage as they crossed the Lower Peninsula.
About 25,000 customers of Detroit Edison, DTE Energy Co.'s electricity production unit, lost power at some point during Sunday's storms, spokesman Len Singer said. Consumers Energy Co. spokesman Jay Jacobs said 14,000 customers lost power.
In Minneapolis, temperatures are expected to be near triple digits in the metro area and dew points are expected to be high Monday, meteorologist Matt Friedlein said. The heat index will approach 105 to 110 degrees, he said.
In Oklahoma on Sunday, temperatures reached 106 degrees in Stillwater in north-central Oklahoma and Ardmore in south-central Oklahoma and 104 degrees in Bartlesville, Lawton and Muskogee.
The thermometer hit 101 in Tulsa and 102 in Oklahoma City, the 17th time this year that the state capital has reached triple digits. That's compared to twice last year and not at all in 2002 or 2004.
Residents of Bismarck, North Dakota., experienced their seventh July day of triple-digit temperatures on Sunday, meteorologist Ken Welk said. The July record for the city is 12 days, set in 1936, he said.
The two-week heat wave blamed for many as 141 deaths in California.
The state had been sizzling in triple-digit temperatures since July 16. Several cities set records for extended heat waves, including Fresno, with six consecutive 110-plus-degree days, and Sacramento, with 11 consecutive triple-digit days, said Cynthia Palmer, a National Weather Service meteorologist in Sacramento.
Twelve people were taken to hospitals after suffering heat-related illnesses at an international scout jamboree Sunday in Maryland.
The jamboree in Darlingon was organized by the Polish Scouters Association, and it included children from Australia, England, Poland, Canada, Argentina and the United States, said Reed Blom, the director of Camp Spencer. None of the illnesses was considered to be serious.
Among those sweating it out in Michigan were 8,000 Boy Scouts attending a national conference at Michigan State University in East Lansing -- and sleeping in mostly un-air-conditioned dorms. Organizers of the National Order of the Arrow Conference had 20 to 25 medical professionals on hand.
Scouts were being warned to pay attention if they started feeling the effects of the heat. "Get indoors, take it easy," Order of the Arrow director Clyde Mayer said. "The Boy Scout motto is, `Be prepared.' And I think our guys will be."