I have been waiting for someone to start a thread - not as many chasers down in this region as there are out west.
GFS is furthest west with the track of the primary low. It has been fairly consistent with showing a track through Arkansas and Southeast MO - has actually trended a bit west over the last few runs. NAM is further to the south and east and takes the primary low through MS. GFS seems to occlude fairly early, as well.
Several rounds of severe weather will be possible with this system and this will make Fridays forecast more difficult and could even jeopardize the significance of the outbreak. Complicating matters will be system 1 tonight - system 2 tomorrow night and Friday morning and then round 3 on Friday afternoon into Saturday.
The models have been slowly catching up with how the low level jet will unfold - with SREF showing high numbers on the "tornado ingredients" prog for the last few days. SREF has a bullseye over Southeast AR/LA/MS into AL with the above mentioned prog. Seems to peak Friday night (late) over LA and southwest MS and then a second peak between 3 pm and 10 pm over much of MS and extending northward into West TN and then into Alabama, as well. SREF is showing 30-50% bullseye for Friday. Again it has been showing this for several days now - with little change in numbers. I always find it more important to see consistent numbers - day after day leading up to an event.
Track of the low is critical for the placement of the highest tornado potential. Winds should back to the southeast during Friday afternoon over portions of MS and AL - TN. 850 wind fields of 40-60 knots - depending on your model of choice - are showing up over the same region. A strong 500 mb wind max also pushes into the TN Valley on Friday night. Speeds of 100-120 knots are indicated by the GFS over the Arklatex region into southeast AR/North LA. Neutral tilt turns negative on Friday night into Saturday.
CAPE readings have been consistently showing up in the 1000-3000+ range over a large portion of the SPC outlooked area for several days now. GFS has been indicating very high CAPE readings for a number of days now and has shown little change this afternoon. Dew point readings from the middle to upper 60s (even some 70s) push all the way into Arkansas/Mississippi on most models.
There appears to be some question on just how much wind shear is realized with differing opinions from one model to the next. If the low actually does deepen as being depicted by the GFS and some other models then common sense would say that a strong low level jet will develop in response to the deepening low.
I would pick a line from Memphis, TN to Florence, AL and then back down towards Jackson, MS and perhaps southeast AR. This appears to be where the best dynamics will come together, although northern LA and southern AR could see higher CAPE values. Timing of day could be an issue, as well. Although the warm sector is rather broad and the potential for several lines and areas of severe weather will exist. The Memphis, TN - Jackson, MS - Birmingham, AL NWS Offices have been hitting the potential pretty hard in the area forecast discussions and hazardous weather outlooks.
If the low does move further south and east then I would prob try a Jackson - Mobile - Birmingham triangle.
Highest instability being progged for Friday afternoon and evening is actually over AR and Northern LA - CAPE values exceeding 3000 are and have been showing up on the models. Potential for some very large hail will exist in portions of the SPC outlook. Tough chasing in AR, though.
Another question is whether or not a couple of supercells can form closer to the low and along the warm front - if that were to happen then the tornado risk would be enhanced closer to NE AR and into the MO Bootheel and NW TN (assuming the track of the low is close to what the GFS is indicating). Obviously this has greater implications for my region and has been of interest to me since last Friday. Right now it appears most of the KPAH region will be out of the highest risk zone and perhaps will have to deal with elevated convection or some secondary risk on Saturday (see NAM with spiked instability for Saturdays event).
KGWO (BUFKIT) in MS shows CAPE values of 2700+ at 7 pm and 2500+ at 10 pm/ KI of 40+/ sweat index of 600+/ TT of 55+/ BRN of 21-23/ 850 winds increase from 18 knots at 1 pm to 55+ knots by 7-10 pm period/ significant tornado index is greater than 5/ supercell index is greater than 6/ all between the same hours mentioned above. Also noticed on BUFKIT that winds at low levels could actually be east/southeast with plenty of turning with height.
Way too early to determine how Thursday nights activity will come into play - will there still be a lot of cloud debris around on Friday morning or will it clear out of the region in time for destabilization to occur on Friday morning into the afternoon hours? Placement of boundaries? Will the low actually deepen as much as the GFS is indicating? Another question on the table.
A second peak of instability is being shown by the NAM over KY and TN on Saturday afternoon - just southeast of the deep low.
The potential for Friday's event is pretty high - the signal for this event has been on the models for more than 5 days now. It appears SPC is talking about at least a moderate risk and hinted at even higher for Friday. However, with the event still be 48 hours away there should probably be a lot of caution used in trying to pinpoint how this unfolds. Thursday nights thunderstorm complex will be important in how Friday evolves and could really reduce the severe weather threat.
Good luck to anyone chasing - not the best area to chase storms.
EDIT: Developmental RUC now comes in with a low even further west and stronger - showing the primary low passing into eastern Oklahoma. 0z NAM is now further east and south taking the main low through southeast AR and into MS. Cutting the differences between all models would give a track through AR and into MO/IL/KY.
Edit: Also the new day 2 is a large slight - mainly because of some of the factors listed above. The first round of thunderstorms on Thursday night and Friday morning could really complicate how Friday afternoon evolves.
