Severe storms fire up to start week
Weather.com -- On the heels of a hot finish to July across much of the southern U.S., another string of hot days continues.
And that is setting records not necessarily for the magnitude of the heat, but for its longevity in parts of Louisiana, Texas and Mississippi.
Jackson, Mississippi, may tie a record streak of days with highs of 95 degrees or hotter Monday, set in the late 19th century (29 straight days from July 22 - August 19, 1896), according to the National Weather Service office in Flowood, Mississippi.
While the Mississippi capital's average high this time of year is in the low 90s, a streak lasting four weeks is quite a feat, historically.
Take a look at the summer scenes across the country:
Baton Rouge, Louisiana, shattered its record for days with highs of at least 94 degrees, with the streak currently at 33 straight days through August 9, according to the National Weather Service in Slidell, Louisiana.
Finally, Galveston, Texas, hasn't seen the temperature dip below 80 degrees since two days before the Fourth of July holiday, topping a record streak of 36 straight days set in 2011, the second hottest year on record in the Lone Star State.
Through early this week, triple-digit heat will continue to bake much of the Southern Plains and Lower Mississippi River Valley. As of Monday morning, more than 30 million people were under heat advisories or excessive heat warnings across those regions.
If 100-degree heat was not bad enough, high levels of humidity will make it feel even more uncomfortable.
With dewpoints forecast to remain in the 70s for several days, the heat index -- or the temperature it feels like when you factor in the humidity -- is forecast to rise to near or even above 110 degrees in many locations into at least Tuesday. The hardest hit areas will be across Oklahoma, Texas, Arkansas, Louisiana, Mississippi, and Alabama.
On Sunday, the heat index peaked at 118 degrees in Slidell, Louisiana. Almost equally as miserable was Tulsa, Oklahoma, where the heat index was 114 degrees in Little Rock, Arkansas. Dallas-Ft. Worth International Airport recorded its hottest day of the year Sunday, rising to 106 degrees.
(MAPS: 10-day Forecast)
Daily record highs may be challenged in the following cities the next couple of days (current record is in parentheses):
The hot weather is associated with a ridge of high pressure in the upper levels of the atmosphere. This ridge is centered right over the southern Plains right now. However, it is influencing a broad area of the South with sinking air motions that suppress thunderstorm development. This will deflect most rain and thunderstorm activity to the north, meaning much of the period will not only be hot, but short on rainfall as well.
Rainfall is one thing several Texas cities saw none of in July. The city of Tyler, Texas, marked its first rainless July since continuous recordkeeping began at the airport in 1984. Longview and Waco each had their first rain-free July since 1993. Waco has had 40 straight days with no rain through Sunday, which is the longest dry streak there since 1952, according to the National Weather Service. In Louisiana, Monroe just experienced one of its top 10 driest months of July on record.
Even locations very close to the Gulf Coast, including southern Louisiana, are feeling the effects of the oppressive heat and humidity. Being east of the high-pressure center means winds will tend to blow from the north. While that's a cold wind in winter, it's a wind blowing off sun-parched land in summer and preventing the moderating effects of the Gulf of Mexico from having as much of a cooling influence.
Some relief is possible by the second half of this week as the upper-level ridge is expected to shift farther west, taking the hottest of the hot air with it.
To be sure, this will only take a few degrees off the highs later this week in the most heat-weary parts of the southern Plains, Gulf Coast and Lower Mississippi Valley.
However, perhaps the biggest change will be in the humidity. Drier air flowing southward should send surface dew points tumbling below 60 degrees beginning Wednesday in parts of Texas, Louisiana, Arkansas and Mississippi. It may even take humidity down a somewhat imperceptible notch along the immediate northern Gulf Coast.
Senior meteorologist Jonathan Erdman contributed to this report.