UPDATE (12:30 pm 2/22): The SPC has already issued a Moderate Risk for parts of Louisiana, Mississippi, Alabama and Florida for 2/23 for damaging winds, hail, and strong, long-track tornadoes. Everything seems to be coming together.
It’s starting to look like a potentially significant severe weather event will affect the Gulf Coast states and the Carolinas. As models have been coming into better agreement, the event is looking likely. I would like to say that at first, this could be a high-impact and significant severe weather event, and a tornado outbreak is possible.
Starting into specifics: As a shortwave trough digs into the Southern Plains, a surface low will develop in Northern Mexico and track northeastward. The exact strength and timing of this low will be critical in determining specific timings and threats, but per the 0z Euro on 2/22/16, the potent 988mb low will be in Northern Louisiana around 6pm on 2/23. This low will move to near Columbus, Ohio by 6pm on 2/24. The wind fields and associated shear values are impressive, to put it mildly. An intense jet streak will round the base of the trough (100+ kts at midlevels) and the low-level jet will be cranking, maxing out at or above 70 knots.
This is a sounding from the 2/22 0z NAM4-km run for 3 pm on 2/23 near Lafayette, Louisiana. Even with a little veer-back-veer, this is a very impressive sounding. Note the SRH values of 500+. Any storms that form will be able to easily rotate. Perhaps even more worrisome is the threat overnight 2/23-2/24:
This sounding is for 12 am near Dothan, Alabama. SRH values are even higher than earlier. The potential for nighttime tornado activity is rather ominous. Should also note that with both of these soundings, storm motions will be quite fast. Further northeast into the Carolinas, there is also a significant threat, especially during the afternoon and evening in central and east North Carolina. This part will be updated as we grow closer to the event.
All in all, I’m getting fairly concerned with this setup. The event on February 15-16 had quite a few tornadoes, a few of which were strong, including the Century, Florida EF3 (which was the first EF3+ in Florida since the Groundhog Day outbreak of 2007). Everyone in the Gulf Coast areas should have ways of receiving warnings, especially with the overnight threat. With everything said, here are my current thoughts:
Storms will fire overnight in Central Texas on Monday, February 22 and track eastward. Initially, these storms will likely be mostly elevated with some hail, but any surface-based storms could produce an isolated tornado or two. The threat will start to ramp-up substantially by noon on 2/23 in Southeast Texas, possibly affecting the Houston metro. During the afternoon, the storms will quickly move eastward into Louisiana and Mississippi and the parameters will increase for tornadoes. Some significant/long-track tornadoes will be possible starting in the afternoon in Louisiana. By nightfall, storms will likely be in Southern Mississippi and moving into Alabama and the Florida Panhandle. The tornado threat will NOT decrease during the night, as the parameters do not decrease with time. By daybreak, the storms will be from Central Georgia into Florida. At this point, the storms may weaken. However, during the day on 2/24, it appears possible that storms will restrengthen in the Carolinas, and the significant severe threat there will be in the afternoon and evening on 2/24.
My prediction for number of tornadoes is 12, with a couple of them strong.