This looks like an interesting northwest flow severe setup. Just looking at wind fields, the Arklatex region can expect a general WNW flow in the upper levels, backing to southerly near the surface. More than adequate deep layer shear supports enlarged hodographs and plentiful storm relative helicity across the area Saturday afternoon and night.
In the upper levels, the main vortmax is progged to be transversing the central Plains at 00z Sunday with lead shortwave energy more or less sliding down the Red River Valley towards Arkansas/Louisiana, where a surface low is forecast to develop over North Texas.
The focus for severe appears to be from East Texas into much of Louisiana and southern Arkansas. The models vary with placement of the surface warm front Saturday afternoon, but the consensus seems to be generally from the Red River to the AR/LA border region.
Running through some of the red flags first, there is the potential for considerable ongoing convective activity from mid morning through midday Saturday in vicinity of the warm front, which may limit surface heating and lead toward messy/clustered storm modes near the warm front. While the warm sector from East Texas into Louisiana is forecast to see much better surface heating, the 3km NAM insists that warm air (14-18C) in the 800-850mb layer noses across Texas. This scenario creates a capping inversion over East Texas, despite large CAPE values over 2,000 J/kg and higher end severe parameters, i.e. STP and SCP.
I think with all things considered, central to northern Louisiana seems to have the best shot at favorable thermodynamics, working in concert with large, clockwise curving hodographs, assuming the area isn't convectively overturned during the morning/early afternoon period. Even in that worst case scenario, you could probably still have embedded supercellular structures given wind profiles (WNW at 500mb to S near the surface is going to allow updrafts to rotate fairly easily), as well as the potential for some discrete warm sector activity, south of ongoing convection, but east of the capping inversion.
If the lead shortwave/perturbation dives in only a little bit quicker, I could see an MCS developing over the Arklamiss area by midday Saturday and racing across Mississippi with damaging winds and marginally severe hail being the main threats. That scenario would leave limited forcing in the wake of this convective system, despite strong surface heating in areas like East Texas and western Louisiana.
One also has to consider the position of the warm front. If morning precipitation is widespread, you may see a convectively reinforced boundary/effective warm front remain farther south, perhaps across Louisiana, as advertised on the last few runs of the 3km NAM. That would keep most, if not all of Arkansas on the cool side of the system, mitigating any severe threat there. However, if early day activity is not as widespread as currently progged, the warm front could easily lift into Arkansas and you may have a better shot at discrete warm front activity, but I don't think that scenario is probable at this juncture.
It's tough to find any really close analog matches, but I came out with a couple that are loosely matched to Saturday:
3/26/11 - Widespread severe hail across the mid-South/Southeast with a few tornadoes across AL/GA. Only a few isolated severe reports farther west near the surface low and cold front in TX. This analog is displaced at least a few hundred miles to the east, so the geographic placement isn't perfect.
3/28/14 - A better matchup based on the surface features and geographic placement, although one large caveat is that surface heating across East Texas was more impressive than we'll probably see on Saturday, as midday surface temperatures had warmed into the mid-70s as far north as the Metroplex by 17z. Temperatures this time around will probably be 5-10 degrees cooler at the same time. Nonetheless, that event produced quite a bit of large hail from East Texas into southern Arkansas, with damaging winds common into Louisiana.
I won't be out chasing, but I think Louisiana would be the sensible play, unless you're an East Texas local and want to backyard chase, then you wait at home and see if the cap can be breached and perhaps isolated convection manages to form before going too far east into the jungle. Maybe something could go up on the dryline, but displacement from better forcing aloft and warm 850mb temperatures don't excite me.
Overall, the setup looks to yield fairly messy results (and/or a cap bust in East Texas), but I always like northwest/west-northwest flow events, especially where surface winds are still southerly and instability is favorable.
