03/01/07 FCST: AR / MO / KY / TN / AL / IL / MS

[Perry Williams]

Well this mornings model suite make me ponder again.. I noted that the UKMET bombs the low out at an amazing 978 mb!!!! This may be a little unbelievable though. Furthest southeast of the models would be the GFS. Which takes the low just west of the MS river valley.. Up here in IL initial threat is going to be nocturnal convection. Possibly severe. Dont know how the storms will hold together this time of year.. Moisture still looks to be fine.. I agree with the SPC outlook.. I think they could be further N or NW.. But the highest risk in the day 3 looks appropriate. When this system comes on shore, hopefully these finite details can be resolved.

Yes, and the 12z NAM and GFS deepens it to 977 and 981 mb respectively over eastern Iowa/ SW Wisconsin.

 

[Justin E. Reed]

This system is continuing to show prolific shear profiles with a military only model run . I have gone back into archives and the following events are similar to this set up. April 8 and 16,1998 and April 7,2006. This is a situation that is likely to get going, and very explosively, one model I ran just now, took a normal thunderstorm to supercell with strong rotation in just 2 hours! WTF! I am stressing this is a dangerous situation, I am expecting a rather sizeable outbreak, powerful supercells with incredible gate to gate shear and a possible prolific squall line, if not supercells for Atlanta, all the way the Tallahassee. We'll see how this pans out, by I am predicting a dire weather situation to kick off March. This one is not a lion, this is an elephant on crystal meth, I'm keeping my relatives abreast to this likely dangerous situation.

 

[Justin E. Reed]

After letting the model run for another hour, the storm that I made(mentioned above), at the 3 hour mark, has radar velocities maxed out, a total gate to gate max out. This is rather odd and I'm sittin here stunned and confused, but hey, its the computer running it. Highly worried about NE MS, N AL and Mid TN, this is a very volatile setup.

 

[Dan Dawson]

After letting the model run for another hour, the storm that I made(mentioned above), at the 3 hour mark, has radar velocities maxed out, a total gate to gate max out. This is rather odd and I'm sittin here stunned and confused, but hey, its the computer running it. Highly worried about NE MS, N AL and Mid TN, this is a very volatile setup.

I'm curious. What model are you using, and are you initializing it with an inhomogeneous analysis, like the operational forecast models, and running at high resolution over a limited domain, or are you taking forecast soundings and initializing small, idealized domains with a thermal bubble to see what kind of storm structure you get?

 

[Justin E. Reed]

I wish I could say, but it is SECRET material under Dept. of the Navy. It utilizes every single bit of information that you can gather, soundings are one of the better parts of it. I just can't say too much, but the fact that my Commanding Officer was freaked by this output of the model, raises a big red flag, stations in Nashville are already starting to get a little gloom and doom over this, for all the right reasons.

 

[George Tincher]

I really hate comparing systems and I hate even more to hype systems. But I can't help seeing a big event shaping up when I look at Thursday. And it is somewhat comparable to other systems that have really caused lots of problems for areas of the south such as TN, MS, and AL. The person who said it's possible that this may end up being a high risk before all is said and done may end up being correct. It's certainly a very solid moderate. I see a much more favorable severe weather setup for this one than with the last system. Moisture looks much better for one thing and it appears decent moisture levels and increased sfc tempertures will make it much farther N than last time, which could make this one a bit more widespread. This setup appears to have much more in common with what you might expect to see in April, rather than what you would expect to see in February (the previous system).

So far I think the SPC has done a good job highlighting the areas most at risk, but I would not be too surprised to see areas farther N into KY, SRN IL and SRN IN get in on the action as well, if good moisture proves to not be an issue.

That said, right now it appears that cities such as Memphis, TN....Nashville, TN....Columbus, MS....Huntsville, AL....Birmingham, AL....etc, may be in for a very long and a very rough day come Thursday. Now I'll need to go look at the latest model data as it comes in to see if everything I have just typed has gone out the window or not. Hehe.

 

[Dan Dawson]

I wish I could say, but it is SECRET material under Dept. of the Navy. It utilizes every single bit of information that you can gather, soundings are one of the better parts of it. I just can't say too much, but the fact that my Commanding Officer was freaked by this output of the model, raises a big red flag, stations in Nashville are already starting to get a little gloom and doom over this, for all the right reasons.

See the new thread I've opened up on the "Weather and Chasing Board" about this topic, since my reply is somewhat off-topic.

http://www.stormtrack.org/forum/showthread.php?p=124169#post124169

 

[HAltschule]

one model I ran just now, took a normal thunderstorm to supercell with strong rotation in just 2 hours!

This actually seems unimpressive to me in the sense that many times we see thunderstorms develop and become tornadic with great shear values in 1/2 or so. 2 Hours seems like a long time for a TRW to go tornadic with those shear values in an explosive environment.

Nevertheless, it looks like potent setup and one that should be fun to watch. As far as the Navy model goes, it's hard to comment on it or it's performance when you don't know anything about it.

 

[Justin E. Reed]

Well, I'm prepping the system to run at 2300L, it is showing a change,. ironically you metinoed half the time, the whole model system is collecting the newest data and is processing for a run. The run should be done by 2330 or just after 0000L. I will definetly post my new findings as soon as they come flying out of the printer.

 

[Skip Talbot]

I'd imagine the Day 2's slight will extend well into central Illinois. Earl Barker's NAM CAPE plots have 500 JKg extending up to about Springfield. At 18z Carbondale looks pretty good. 750 JKg isn't much, but with the 979 low in IA, 60 knots 6km shear, 40 knots 1km shear and 300 3km SRH, the meager instability will be more than made up for by the dynamics. I'm looking at 18z because the cap looks pretty weak and there may be quite a bit of forcing with the jet as strong as it is. Early show in southern IL?

 

[Brandon Sullivan]

Looking at the latest SREF run, wondering if here in western Il will be put in the slight risk tomorrow?? Latest suite of models are lesser with instability.. WRF NGM ECMWF still the furthest Northwest with the track of the system. Even with the lack of instaility. I think LI TT and Moisture and UVV should be enough to kick off some severe convection.. I personally would see this as a linear system, with some mini or embedded supercells.. Especially with the further northwestward extent. Im hoping for a slight with the new outlook tommorow.. And the NW trend to stay around!

 

[ReidVaughan]

Looking to Thursday...

I too imagine that it will get the moderate go ahead. The weather service office in Jackson stated in the 0331Z Forecast update that, "a severe weather outbreake possible after midnight Wednesday nigh to Thursday afternoon."

Indeed, for as long as I have followed the weather as a EMA/Public Service official, I have never known the Jackson weather service office to cry wolf. If anyting they are usually very conservative in their outlook and even they have begun to issue states such as the below...

THIS REALLY FITS WELL WITH STORM INITIATION ACROSS THE W/NW
PORTION OF THE CWA THEN AS THE SUPERCELLS TRACK NE...THEY WILL HAVE
TIME TO MATURE/EVOLVE WHILE MOVING INTO A MORE FAVORABLE ENVIRONMENT.
THIS SUGGESTS THE POTENTIAL FOR SIG TYPE SVR STORMS ACROSS THAT NE
HALF OR NE ONE THIRD OF THE CWA. YOU CAN VIEW THE CURRENT GRAPHICAST
WHICH DEPICTS THIS SCENARIO.

Continue reading the Jackson AFD here.

 

[Justin E. Reed]

Ok, my latest model runs are complete and that red flag is a big one now. Temps WILL range from 70-75 and DPTs in the 61-66 range in this area. Shear profiles have somewhat deepened and become stronger. Any storm that taps just right, is HIGHLY likely to drop a tornado. Supercells will be very classic of the Great Plains, it seems many willa actually be more LP than HP. The latest storm intesity growth model that we have, shows storm to intense rotation in as little as 45 minutes, I literally dropped my coffee on that one. This is a system that will not be nice, we'll easily see over a dozen tornadoes, and would not shock me to see several violent ones. HSV, BNA, BHM, MEM, JAN, and even FFC(Atlanta) and MOB will have to watch this with keen eyes. A squall line is likely to translate into the Carolinas, most of GA and NRN FL, possibly even LA. I'm not throwing my back to this one like the last system. This one has everything going for it, moisture, temps, shear, jet, everything seems to be falling into place. A high risk may be put out as early as tomorrow afternoon for THURS by indications, and a MOD risk for today in AR, MO, AND NRN LA. I'm already starting to sweat because much of my family is in the bullseye for this one. Yall that can chase this, get ready, this one may blow you away.

 

[Justin E. Reed]

Well, slightly off from where I was thinking, but this puts me in a very dangerous position. Jacksonville is right near the edge of some extreme severe weather.

SPC
http://www.spc.noaa.gov/products/outlook/day2otlk.html

 

[SteveCarter]

Seems like most models are coming together a little better now, and of course a MOD has been issued for Thursday. Still would not be surprised to see a HIGH risk, but MOD is still pretty good this far ahead. Instability could be the only drawback here, but.....with the shear like it is...WOW. Pinpointing this is a little tricky, as there are different areas popping up on different sites. This is a more widespread event than last weekend. My target area has shifted south to the Tuscaloosa, AL area, but would not be surprised..at all, to see things popping further north...all the way to Nashville. I'm really impressed with the dewpoints and the actual temps, and with that shear!.....this should be an awesome day! btw...the local forecast here in Anderson, SC is already calling for severe storms thursday night.