Southern Heatwave Buffers, Slinks to Southwest

Despite relinquishing some territory from its swelter, the heat wave across the nation's south still burdens tens of millions as it refocuses further west.

Fueled by a persistent dome of high pressure, August's heat wave across the south persists, but it is beginning to tilt. In the southeastern quadrant of the nation, the dome is beginning to vacate, with multiple fronts and upper-level disturbances punching cooler air southward. However, many areas east of the Rockies today will continue to feel torrid temperatures.

Heat indices, which account for the high humidity present, will peak between the century mark and 115 degrees in Florida, the coastal Southeast, the Deep South, and the Mid-South.

As heat in the Southeast retreats, the heat dome slides to the southwest and builds a drier but searing heat for folks west of the Rockies today too.

Real high temperatures in the Sonoran and Mojave Deserts, the valleys of the Great Basin, and areas away from the immediate coastline of southern California, such as the southern San Joaquin Valley, will observe temperatures cresting above the 100s and 110s. In the lowest places amongst these regions, such as in Death Valley, temperatures will even approach the 120-degree mark.

If that were not enough, the overnight period will retain heavy heat in most areas, namely across the coastal southeast where ocean humidity can inhibit cooling. Parts of the Desert Southwest, Mid-South, Gulf Coast, and southern Atlantic Coast will only drop to the 90s or mid-80s just before sunrise.

With little overnight cooling, energy grids and connected air conditioning across these areas will see high stress and a heavy workload, which could cause blackouts where the grid is not adequately prepared. Vulnerable populations, including children and the elderly, are at the highest risk for heat-related illnesses where high temperatures persist overnight.

Heat Advisories have been posted for inland areas of southern California, northwestern Utah, and southern Idaho, as well as separately from central North Carolina down to Florida and westward to central Texas and southern Oklahoma. Furthermore, Extreme Heat Warnings have been issued for southwestern California, southern Nevada, southern and western Arizona, north-central Texas, southeastern Oklahoma, and southwestern Arkansas.

In areas experiencing extremely hot temperatures, it is exceptionally important to stay hydrated and cool. Avoid exposure to the sun from late morning into the early evening. Make sure to take frequent breaks in the air conditioning or shade, eat and dress lightly, and to use sun protection if outdoors. Always check the back seat before exiting your car, as a vehicle can reach 30 to 40 degrees higher than outdoor temperatures. Never leave kids or pets unattended and remember to “Look Before You Lock!”