Dry and protracted heat wave has a hold on the Southeast
Beginning late-June and early-July, a thick layer of hot, dry air arrived in the Southeast, bringing record temperatures to Mississippi, Louisiana, Texas, Oklahoma, and Florida.
On July 5, temperature gauges at the Gulfport, New Orleans and Baton Rouge airports all registered the highest low temperature recorded for any July 5. Across the US, there were 230 overnight heat records from July 1 through 7 and only 38 daytime highs, according to the National Centers for Environmental Information in Asheville, North Carolina. High overnight temperatures make a heat wave especially unbearable, with little relief from heat and humidity.
Global warming dramatically increases frequency of the most extreme heat events
Extreme heat events are the kind of weather events that increase the most as the climate warms. The more extreme the heat wave, the more likely it is due to the change in the climate. Global warming has led to a dramatic surge in the frequency of the most extreme heat events.
Due to global warming, the most extreme heat events now impact a global area 10 times greater than in the period 1951-1980.
The impact on moderate heat waves is also dramatic, with a seventy-five percent share of moderate heat events now attributed to climate change.
Summer temperatures in the Southeast have ratcheted up since the 1970s
Summer temperatures in the Southeast, consistent with the nationwide trend, have risen steadily since the 1970s. The Southeast has observed warming by as much as 2.3°F since 1970, which averages to 0.4°F per decades, the same decadal rate observed for the contiguous United States over that period.
This ratcheting of blistering summer heat has been fueled by the buildup of heat-trapping greenhouse gases in the atmosphere.