The responsible storm system has shifted east, and a tornado watch was in effect Tuesday morning for the Florida Panhandle. However, the risk of strong tornadoes there is far lower, compared with the areas hit on Monday.
Severe weather began early on Monday in Louisiana, with the first rotating supercell thunderstorm dropping a tornado on Rapides Parish shortly after 11:30 a.m. An approaching cold front from the west kicked up a cluster of spinning storms ahead of a squall line, which tracked north and east as the day wore on.
The first significant tornado developed in Vernon Parish, La., a few minutes past noon. Damage was soon reported in DeRidder.
This tornado quickly intensified, passing within six or seven miles of a National Weather Service Doppler radar site in Fort Polk, La. One person was killed in Vernon Parish, according to the sheriff’s office.
That same storm went on to produce a large tornado near the community of Alexandria, home to about 47,000. A “large tornado” was reported visible just southeast of the air traffic control tower at Alexandria International Airport, according to the Storm Prediction Center.
A rare “tornado emergency” was declared for Alexandria and nearby Pineville as the vortex plowed through. It was the first tornado emergency issued anywhere in the United States since a devastating, mile-wide EF-4 tornado tore a 31-mile path of damage just west of Kansas City on May 28.
The National Weather Service in Lake Charles wrote that the damage swath for Monday’s tornadic storm stretches about 63 miles. However, it’s not clear whether that was one single tornado that stayed on the ground for such a remarkable distance.
Data suggests that an initial significant tornado touched down near DeRidder before perhaps weakening or even lifting in a rural area just northwest of Hineston. The storm’s circulation then reorganized east of Otis near Highway 1199, before moving through northern Alexandria and into Pineville.
Farther to the east, another significant tornado struck just west of Columbia, Miss., along Highway 98. Doppler radar detected the moment debris was tossed into the air as the tornado passed through heavily populated communities.
At the same time, a second potent supercell thunderstorm raged to the north with a nasty circulation evident on radar. This storm also produced a damaging tornado.
The thunderstorm responsible for the tornado near Columbia tracked from southern Mississippi into west-central Alabama, traveling more than 100 miles over 3.5 hours, producing multiple tornado reports.
The long-lived supercell, which is a thunderstorm with a persistent, rotating updraft, finally began to fall apart north of Highway 80 in west-central Alabama. It then evolved into a squall-type structure, which is shaped differently but can still be dangerous.
The northern tip of the line of storms curled back into a “bookend vortex,” producing one or more additional tornadoes near Montevallo, about 30 miles south of Birmingham. According to Doppler radar imagery, debris was lofted thousands of feet into the air as the quick-hitting twister struck.
Meanwhile, another batch of storms had formed near and along the cold front in northern Mississippi. Many of these were not classic discrete supercells, but instead featured embedded circulations near or on the surface boundary itself.
After producing a significant tornado near Guntown, Miss., the storms devolved into a larger complex of embedded rotations amid very heavy rain and wind. Despite a messier structure, they caused widespread wind damage and a few potential tornadoes in northwest Alabama.
Storms finally wound down overnight but continue to pose a threat of severe weather as they move into Florida and southeastern Georgia during the day Tuesday.
Monday’s tornado outbreak produced the first deadly twister in the United States since May 27 and the most severe thunderstorm activity since Halloween.