A stifling heat dome has been baking much of the southern United States for about two weeks now, and it’s showing no signs of relaxing its grip on the Lower 48. An intense pulse of heat is setting records in the Southeast, with highs near 105 degrees in parts of Georgia and the Florida Panhandle, and with heat index values topping 110.
On Wednesday, temperatures as high as 100 to 106 degrees swelled over nine states in the Southeast. More than a dozen cities set record highs, including Macon, Ga. (105), Memphis (102), Tuscaloosa, Ala. (101), Charlotte (101), Nashville (101), Raleigh, N.C. (100) and New Orleans (96).
Wednesday’s 105 in Macon was its highest temperature ever observed so early in the year.
Many of the same areas of the Southeast will continue to simmer on Thursday. The National Weather Service has hoisted heat advisories affecting more than 20 million people from eastern Texas to southern Georgia and the Florida Panhandle.
The most intense heat on Thursday is anticipated over the Florida Panhandle and central and east central Georgia, where the Weather Service in Atlanta issued an excessive heat warning for “dangerously hot conditions.”
The worst of the heat will ease after Thursday, but there are signs a renewed pulse of exceptional heat will eye the Plains and Mississippi Valley into the weekend, prolonging the uncharacteristic toastiness.
Earlier this week, numerous heat records were set from North Dakota to Texas. Notably, Minneapolis hit 101 on Monday, its first time over 100 since 2018. On Tuesday, Milwaukee touched the century mark for the first time in nearly a decade.
More records forecast Thursday
While it will not be as scorching in the Carolinas and Tennessee Valley on Thursday, compared to Wednesday, the zone from Southeast Texas to the Florida Panhandle will be just as hot if not hotter.
“For most places, today will be the hottest day of the ongoing heat wave,” wrote the Weather Service office in Tallahassee.
The hottest weather of the heat wave is today. Many temperatures records will be broken. Widespread highs of 100-104 degrees. A Heat Advisory is in effect. Avoid strenuous outdoor activity during the afternoon hours. #FLwx #GAwx #ALwx https://t.co/sDZ77FzLJQ pic.twitter.com/V6iBZG3Cr3— NWS Tallahassee (@NWSTallahassee) June 23, 2022
In some places, the heat and humidity will combine to yield heat indexes exceeding 110 degrees. That will make for hazardous conditions that can lead to heat exhaustion and heat stroke for those exerting themselves outdoors.
Here are a few of the highest forecast temperatures, and where records are expected to be established:
Dallas: Record tie likely. The high is forecast to hit 102, matching the mark set in 1980.
Houston: Record tie likely. The high is forecast to hit 101, matching the mark set in 2009.
Mobile, Ala.: Record tie likely. The high is forecast to hit 101, matching the mark set in 2009.
Macon, Ga.: New record likely. The high is forecast to hit 102 degrees. The record is 101, set in 1988.
Albany, Ga.: New record likely. The high is forecast to hit 105 degrees. The record is 104, set in 1944.
Tallahassee: New record likely. The high is forecast to hit 104 degrees. The June 23 record is 103, set in 1944. The city could flirt with its all-time record of 105.
Blame the heat dome
Heat domes are ridges of high pressure. They feature mostly clear skies, sinking air and copious sunshine. It also deflects the jet stream farther north into the Upper Midwest or southern Canada, deterring any inclement weather systems.
The stronger the heat dome, the hotter the air mass. The European weather model simulates temperatures at the 850-millibar level, about a mile above the ground, that are in the unprecedented category. Anything magenta in the plot connotes something outside the data set of historical observations.
By Saturday, the heat dome will shift west a bit, bringing readings of 100 to 104 degrees to most of Texas, Oklahoma, Arkansas, Louisiana and Mississippi away from the coastlines, western Alabama, western Tennessee and southeastern Missouri.
There are signs that the heat dome could ease or eventually break apart into early next week, but the National Weather Service Climate Prediction Center continues to highlight odds of continued above-average temperatures for weeks to come.