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

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 :)
 
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
 
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)...
 
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
 
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.
 
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:
 
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...
 
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...
 
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. :)
 
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.
 
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
 
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!
 
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.

:p
 
Well according the the lastest ETA 12Z run that might be a good place to be at 18Z. It has precip starting in that area, cape around 1000J/kg and the surface low is right there in north central OK around that time frame. Unlike the last run the cap in that area, by 18Z, is almost non existing but any time before 16Z or so the cap will be very strong and that is a good thing. I think that could be a good place to start at least right now. Tomorrow morning analysis will paint the real picture.

Mick
 
I have a hard time believing that the cold air in place right now over the suggested 'region of interest' is going to move as far north as advertised by the ETA model. I'd shift things south - relative to the suggested target of the KS/OK border. That said, I'm not sure I'd try chasing this event even if I lived in the area. Not really much to get excited about in my opinion.

Glen
 
Originally posted by Glen Romine
I have a hard time believing that the cold air in place right now over the suggested 'region of interest' is going to move as far north as advertised by the ETA model.

I'm not sure I'd try chasing this event even if I lived in the area. Not really much to get excited about in my opinion.

Glen

Why do you think the cold air will not push as far north? I am just curious.

I will probably not chase myself because of work, but tomorrow morning will be the pivoting point in my decision whether I go or not.

Mick
 
Originally posted by Mickey Ptak

Why do you think the cold air will not push as far north? I am just curious.


Models generally handle shallow cold pools very poorly. The model tendency is to mix out the cold surface air with warmer air above as the shear can be quite large across the poorly resolved boundary - and the model solution to large shear is increasing mixing to maintain stability, and this process can exceed phyisically reasonable rates. The atmosphere may well prove me wrong (sure wouldn't be the first time) - but I can recall past experiences where moist and shallow cold air just doesn't like to move, with persistent drizzle reinforcing the boundary. Just looking at the current temperatures compared with the 12Z model forecasts suggests the ETA is warming too rapidly in this region. RUC model, which has better resolution, also is slower than the ETA in bringing the warm front north.

Glen
 
Somehow, this is starting to remind me too much of April 19, 2003. That day was cool, damp and drizzly, and the early HWO's kept calling for severe to develop. Then the 1 PM HWO mentioned the dryline was pushing east, right before the Tulsa NWS called for a Skywarn activation. A tornado hit Dewey and killed 2 or 3 people.

I'm just a great big ray of sunshine, ain't I?
 
Originally posted by Douglas D. Lee
... A tornado hit Dewey and killed 2 or 3 people.

I'm just a great big ray of sunshine, ain't I?

Damn, where was I? LOL

I'm still betting on a squall line... Haven't checked the latest 18Z data, but I'm sure it's very similar to the 12Z run. I would say that east central OK would be the best bet -- Right on the nose of warm air, decent instability, weak CAP, and good shear. That's where storms will likely be supercellular to begin, rapidly translating into a squall line...
 
The 00z Wednesday ETA run looks terrible. Vort max is very elongated. this is not the same setup I had hoped for, and the models had been slowly leaning towards this solution. Not too mention the cirrus deck that's moving into the plains and will be over the eastern half of Oklahoma. That certainly won't help the rather thick stratus deck that is currently draped across much of Oklahoma. Not to say there can't still be storms in eastern OK which are initially supercells. But they will quickly evolve into a squall line.

I can't justify the long drive up there. Looks like a no go for me. Rats.
 
Well, here is my shot at it. I think initation will be around 4:00 PM about the OK, AR boader. Due to a thin and broken cloud cover east into AR with daytime heating into the mid 70's and plenty juice a few sup's will get going really fast. The squall line will develop along I-30 north east into south east MO. with a few embedded tor's. Bows and wind will be more the norm for this one.

That's my 2 cents worth. We'll see. If they are out there I will be too.
 
Originally posted by Douglas D. Lee
Somehow, this is starting to remind me too much of April 19, 2003. That day was cool, damp and drizzly, and the early HWO's kept calling for severe to develop. Then the 1 PM HWO mentioned the dryline was pushing east, right before the Tulsa NWS called for a Skywarn activation. A tornado hit Dewey and killed 2 or 3 people.

I'm just a great big ray of sunshine, ain't I?

Are you sure about the date? I did a quick search and found this site with some plots of weather conditions for that event:

http://www.hookecho.com/events/2003/04_19_...9_03/041903.asp

Scroll down the page a bit and you should find them. I really don't see many parallels at all between what is forecast for tomorrow and that event.

Tonight's ETA run suggests high to mid-level clouds will be over much of OK, a sharp front will struggle to push north of the KS state line, with a dryline dropping from the low, which may have a limited push for lack solar heating. Surface moisture forecast by the ETA to mix out strongly - with only upper 50 dewpoints reaching ne OK. If better moisture is present, then you might be able to bump CAPE forecasts up a notch, which are only in the 500-750 J/kg range right now. Surface winds actually look better this run - but the strength of the deep layer shear may be too much for the limited instability. Convection in the warm sector may not develop until the cold front starts to swing in behind the low after overcoming the dryline - near darkness - around extreme se KS to ne OK. Some severe hail reports look possible early, then as the front begins the push and upper flow becomes more perpindicular to the boundary, a squall line looks likely to develop late over western AR and could pose an increasing severe wind threat. This is how I see it at least.

Glen
 
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