The Southwest is sizzling: Here's where it is expected to hit 115 or more

Scorching heat is blazing across the Southwest this week: Both Phoenix and Yuma expected to flirt with 115 degrees Wednesday and over the next few days.

Smaller cities such as Lake Havasu City, Arizona; Laughlin, Nevada; and Needles, California; are all forecast to hit 115 degrees Wednesday and for each of the next two days.

Las Vegas should hit 110 degrees by Thursday.

Although it's August and the Southwest is supposed to be hot, these readings are even extreme for the region: Excessive-heat warnings have been issued Wednesday for about 16 million people, including the Phoenix and Las Vegas metro areas, the National Weather Service said.

An excessive-heat warning is issued because of "a prolonged period of dangerously hot temperatures," the Weather Service in Las Vegas said.

"An excessive heat warning is in effect for the lower elevations of southern Arizona to central California for afternoon high temperatures in the 105 to 115 degree range, and overnight lows only in the middle 80s to near 90 degrees for the warmest locations," the National Weather Service said.

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Blistering temperatures of 105 to 125 degrees will blaze across the Southwest and California on Wednesday and the next few days.

In Las Vegas, Weather Service meteorologist Trevor Boucher told the Review-Journal that "people should double check on animals, children and anybody. Hydrating frequently is vital."

The Weather Service said to "stay safe from the extreme conditions by limiting time outside, staying hydrated and wearing light and loose-fitting clothing."

For the most extreme heat, head for Death Valley and the Lower Colorado River Valley, where temperatures will range from 115 to 125 degrees, the Weather Service said.

The high temperature in Death Valley on Wednesday was forecast to be 122 degrees.

The extreme temperatures across the Southwest are expected to continue through the remainder of this week, forecasters said.

In the Deep South, temperatures are cooling off slightly Wednesday after a blistering Tuesday, which was the hottest day of the week in the Deep South. Highs reached 100 degrees in cities such as Birmingham and Atlanta for the first time in years. The 100-degree reading in Atlanta was a record high for the day.

The heat index – which is what the temperature feels like when humidity is factored in – soared above 120 degrees in a few places.

Clarksdale, Mississippi, is used to the heat, but the 121 heat index Monday was a little much for the historic Delta town.

"This is crazy heat, even for Mississippi," said Stephanie Davis, 47, the mayor's secretary and a lifetime resident. "I don't ever remember it being worse. The humidity is so high, and it is hot so early."

Heat alerts that had extended northward into the Midwest earlier this week were limited to Gulf Coast states plus Georgia and South Carolina on Wednesday.

The high heat will be replaced by tropical downpours across the South this week. Flood watches are in effect in portions of Florida.

“Heavy rain will continue to plague parts of Florida and the Southeast with a continued threat for flooding into early next week,” AccuWeather said.

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And looking ahead, the final two weeks of August are expected to be warmer than average for much of the U.S., reminding us that the "dog days" of summer aren't quite over yet, the Weather Channel said.

The Northeast and Southwest are predicted to have the hottest temperatures when compared with mid- to late-August averages, according to the Weather Channel. High temperatures should generally be 5 to 15 degrees above average in those regions by early next week.

Contributing: John Bacon, USA TODAY; The Associated Press

This article originally appeared on USA TODAY: Southwest heat: Excessive heat warnings for 16 million people