By Brendan O'Brien
CHICAGO (Reuters) - A heatwave will bake the southwestern and central United States starting on Monday when record-breaking temperatures are expected to soar above 100 degrees (38C), with forecasters warning people to stay indoors and drink plenty of fluids.
A large swath of the nation, stretching from central Nebraska to West Virginia, north into Wisconsin and south into Mississippi will see the heat index rise from Monday morning until midweek, the National Weather Service said.
Midwesterners who woke up on Monday to mild early summer conditions could see showers and thunderstorms in the afternoon before the heat sets in. The heat index, a measure of what the temperature feels like to the human body, is expected to reach 100 degrees by Tuesday afternoon.
The weather service said many areas should expect "well above normal to record-breaking temperatures" as it issued heat advisor and excessive heat warnings for the region.
"Plan ahead to avoid heat-related illness and check on relatives and neighbors. The heat should break toward the end of the week," the weather service said on Twitter.
It also advised people to stay indoors, avoid strenuous activities and stay hydrated with lots of fluids.
The heat was also expected to continue to scorch the Southwest and parts of Texas, where daytime temperatures will remain in the 100s in many parts of the region until Monday night, the weather service said. The mercury reached 114 degrees (45.5C) in Phoenix on Saturday, tying a record for the date.
(Reporting by Brendan O'Brien in Chicago; Editing by Mark Heinrich)