01/12/05 FCST: OK,TX,AR,LA

[Andrea Griffa]

Start this topic for 12th.
I think situation that will be, could evolve in a pretty much interesting way: ETA shows a moderate degree of instability with MLCAPE that could reach 1500 J/Kg overall in central-est TX and south-est OK.
http://weather.cod.edu/forecast/ETA/etaUS_...0_mlcape_72.gif

Low level shear could be also interesting because of the good veering in low levels.

Activity could be limited by surface temperatures not too high but I see from maps that it's forecasted a moderate increasing overal in TX and LA.
http://www.wetterzentrale.de/pics/Rnamavn665.png

Globally it's an interesting situation

 

[Mickey Ptak]

Well this looks very similar to 12/6/04 IMO. From the latest ETA run the cap is going to be very weak and storm initiation will be early at least by 18Z. So any chance of seeing a discreet supercell is going to be around initiation because things will go linear real quick and race eastward IMO. I guess there is a chance for a lone supercell ahead of the line but that remain to be seen.

http://www.mesomick.com/MiscImages/Forecas...ges/ETA_DFW.jpg

I personally am going to arm chair this one unless things change, but who knows.

Mick

 

[Robert Dewey]

Originally posted by Mickey Ptak
Well this looks very similar to 12/6/04 IMO. From the latest ETA run the cap is going to be very weak and storm initiation will be early at least by 18Z. So any chance of seeing a discreet supercell is going to be around initiation because things will go linear real quick and race eastward IMO. I guess there is a chance for a lone supercell ahead of the line but that remain to be seen.

http://www.mesomick.com/MiscImages/Forecas...ges/ETA_DFW.jpg

I personally am going to arm chair this one unless things change, but who knows.

Mick

I agree with you 100%... The CAP appears too weak and the low and mid level forcing is very strong... Even with excellent directional/speed shear and decent instability, things will be stongly forced and most likely linear. Also, things will be moving quite fast...

Still a good setup considering it's January, but probably not worth driving hundreds of miles or more (save the gas money for May)...

 

[Angie Norris]

My beginner opinion thinks Arkansas will see the bulk of the action Wednesday. I think any instabilty for us will be limited by continuing cloud cover, but if the clouds clear out, we could see some explosive development. I would expect storms to begin to fire in eastern OK, and a squall line forming and blasting through far northern LA, AR, and far southern MO (MS would be worth keeping an eye on late in the evening, too). There might be some tornadoes early on if some supercells form, but they will be fast movers (50-60mph). Unfortunately, I'm also thinking most of this is going to be the afterdark-overnight stuff.
Angie

 

[Kurt Hulst]

Yes the set up is looking more promising for these regions for sure. But in fact even if a chase day were to occur we must take into account the terrain in Eastern TX, all of LA and most of AR. I have been in the boot heal of MO, and the eastern stretch down to I40 in AR and that is plains flat very beautiful i can't speak for ever square mile of course but from what i have seen it is nice. but if you ventuer into the Ozarks have fun with all those hills and trees. its terrible. i think many will agree about that. So in my opinion right now two days out i would start at the suggested eastern OK and TX, for the initial storm initiation. But if i could i would wait till the storms got to the Boot heal even though they may be squalled and I wouldn't mind seeing a tornado or two but Lighting is my next preffrence. but to anyone who ventures the best of luck to you.

 

[Kelley Austin]

Kurt,
You are right about the terrain in eastern AR. Anything east of Highway 67 North East from Little Rock and anything east of Highway 65 southeast from Little Rock is not bad chase country. Mostly flat farm land with a few trees here and there. I will be watching the setup real close for Wednesday afternoon. Might have one of those rare chase days around here. :roll:

 

[Jim Bishop]

I'm wondering when and how this talk about a "weak" cap got started. Based on the 12z Monday ETA run, the trough has a slightly more positive tilt to it, owing to more veered 850mb winds during the day; resulting in 12 to 16C 850mb temps. That's one *strong* cap if you ask me! But, if the cap is so weak, explain why the ETA is not forecast precip by 00Z Wednesday? -->Strong cap.

Right now my confidence in this event is much lower since the GFS and ETA are so off on their timing of the shortwave. This morning's ETA forecast doesn't look as good as it did last night.

Hoping for some changes in tonight's run...

 

[Mickey Ptak]

Originally posted by Jim Bishop
I'm wondering when and how this talk about a \"weak\" cap got started.

Well Jim that bit about "weak" cap started with me and this is where I came to my conclusion.

http://weather.cod.edu/forecast/ETA/etaUS_...S_0_cinh_54.gif

I was looking more so at eastern OK and eastern Tx. You are the Met here so I am humble unto you so if I am wrong then I am wrong.

Mick

 

[Robert Dewey]

I was generally speaking of eastern OK as well... The CAP at 12Z is strong, as expected, but then quickly weakens over eastern OK by 18Z and remains weak, possibly the result of large scale ascent across the warm sector (and not to mention SFC heating/moistening). My bet is still on a few isolated supercells to begin with, rapidly evolving into a fast moving squall line...

 

[Scott Taylor]

I can also vouch for good visibility in most of eastern AR, since I live in the area. As for Wed, I'm not counting on much yet, considering the time of year, lack of afternoon chasing hours and low visibility - we'll have a better idea after tomorrow's model runs.

If anything maybe I can grab some lightning shots if a potent squall comes blasting through the area.

Scott, hoping for svr in AR.

 

[Jim Bishop]

Originally posted by Mickey Ptak

I was looking more so at eastern OK and eastern Tx.
Mick

I see, but didn't realize you were speaking of that area. Although the vort max and associated dryline/surface trough (assuming initiation along it occurs) will be further west. That's what I'm focussed on.

Convection in the area you're talking about I believe would be purley off of warm air advection and could be very messy indeed. And the 850 mb temps in that area should be cooler given more of a fetch from the Gulf rather than the warm desert air of the Mexican Plateau. The ETA cin forecast shows a very strong cap at 18z along and ahead of the dryline. But like I said I don't like this run of the ETA.

Sorry for the misunderstand.

 

[Kelley Austin]

Scott,
Where do you live in Eastern AR? If things do start up Wednesday I WILL be out and about. We might run into eash other.

 

[Mickey Ptak]

Originally posted by Jim Bishop+--><div class='quotetop'>QUOTE(Jim Bishop)</div>

<!--QuoteBegin-Mickey Ptak

I was looking more so at eastern OK and eastern Tx.
Mick

I see, but didn't realize you were speaking of that area. Although the vort max and associated dryline/surface trough (assuming initiation along it occurs) will be further west. That's what I'm focussed on.

Sorry for the misunderstand.[/b]

Indeed the area along the dryline is for sure going to be capped at 18Z with cin in the range of -90 to -200 thats one hell off a strong cap. like Robert said the 12Z ETA run does show the cap to weaken by 00Z Thursday. I think at this point the action will start in eastern OK around 00Z Thursday and move its way into AR.

Mick

 

[Scott Taylor]

Hi Kelley,

I live in Marion, AR (work just across the bridge in Memphis, TN). I'm not sure I'll be able to venture far from home at all, since it's usually close to dark by the time I get home from work and picking up the kids. I finally just noticed that you live in Newport. I go through that area when driving to see the parents.

Best of luck if you go out, grab some pics for us!!

EDIT: Sorry group for posting this and going off-topic. I'll PM next time!

 

[Bill Tabor]

Right now generally appears to me the area of interest will begin in the eastern half of OK near 18z. This area will move east and build south into northeast TX by probably 22z or 23z. All the ingredients are there to some marginal degree at least but I'm not too impressed by veered 850mb winds. Probably the talk of the squall line will come to pass. There will be some chance for embedded supercells and possibly some ahead of the line. Because of supercells then small chance for tornadoes as well. If I were SPC I'd probably go Slight and 5% to 15% chance of torns in that area late in the day and into the evening.

I doubt I'll drive as far as the Red unless it looks stonger. There's not a lot of chaseable country between initiation and AR/LA eastern TX. I may look for a more isolated tail end closer to me here in Austin. Probably if I was already in OK, then I'd look for something in se OK around 22Z.