Heat wave continues to cover much of the Southwest

Record-high temperatures are being reported Tuesday in some Texas towns as a heat wave moves over the country's second-largest state and some of its neighbors.

The National Weather Service has issued warnings and advisories on excessive heat throughout most of  Texas, southern New Mexico and Arizona, extreme southern Oklahoma, Louisiana, southern Arkansas, Mississippi, and southern Alabama.

A Twitter post earlier this week by the NWS Prediction Center said the heat wave is "not going anywhere soon" and that "it's CRUCIAL to practice heat safety no matter where you are."

The heat could be potentially very harmful to millions who are in those affected areas.

Meteorologist Victor Murphy with the NWS in Fort Worth, Texas, predicted as the heat wave began to roll across the region that as many as 40-plus million people could be under advisories or warnings this week.

Murphy described the weather phenomenon as a dome which is a still layer of heat that "pretty much precludes any development of any clouds or even showers – just a lot of hot air trapped in that layer." This has been mostly over Mexico, he explained, but has been moving northward and now is over Texas.

Unusually high temperatures for the time of year were recorded in parts of New Mexico and in Phoenix the temperature hit 111 degrees on Sunday, which is 5 degrees above normal for the date and just 9 degrees lower than the record high, the NWS of Phoenix reported. 

Texas GOP Gov. Greg Abbot has added concerns over the heat wave to his disaster declaration which was previously concerned primarily with bringing relief to areas of the state affected by flooding, tornadoes and storms.