Extreme heat alerts in southern US as temperatures hit 120F

The US National Weather Service (NWS) forecast record-breaking temperatures Thursday across the southern US, with some regions expected to reach 120F (49C).

"Record highs and record warm minimum temperatures will be common with the Southeast at the heart of the anomalous heat through today," said the Weather Prediction Center, the federal agency responsible for national forecasts.

Meteorologists noted that overnight lows in some areas will remain as high as the low 80F, which, combined with moisture levels, provides little relief from the intense daytime conditions.

Weather models predict that the state of California will reach 120F through Tuesday, followed closely by 118F in Arizona. Significant heat is also expected in Texas, Oklahoma and Nevada, where peaks could hit 111F. Other states, including New Mexico, Idaho, Oregon, and Washington, are likely to see temperatures between 105.8F and 107.6F.

Extreme temperature gradients

Extreme heat warnings are active for much of the Desert Southwest and portions of the southern Plains to the Deep South, while advisories cover all of Florida and southeast US coasts.

The anomalous warmth contrasts sharply with the upper Midwest near the Canadian border, where temperatures could dip as low as 40F.

The NWS also raised concerns about heavy rain and flash flooding spreading from the Tennessee Valley to the Mid-Atlantic coast. Supercell thunderstorms, highly organized and potentially dangerous storm systems, may produce damaging wind gusts and large hail exceeding 2 inches (5 centimeters) in Nebraska through late Friday. Additionally, monsoonal moisture continues to trigger rain across the Four Corners region, which includes Arizona, Colorado, New Mexico, and Utah.