4/13/07 FCST: TX / OK / AR / MO / IL / TN

[Chris C Sanner]

Truthfully, I am carefully eyeing a possible cold core scenario under the low in SW Oklahoma. Instabilities around 1000-1500 j/kg with easterly surface flow and some modest dewpoints. Not the most ideal tornadic environment but we know how these scenarios can reward with less than ideal conditions. Plus it is a lot better chase terrain among other things over Eastern Texas. I also think its pretty apparent that the activity there tommorow might be embedded in a bunch of junk which isn't fun. A lot can and will change but I am definitely split on which one to head for tommorow.

 

[Ilya Neyman]

Latest models are significantly slowing the evolution of the surface features for tomorrow, in fact both this morning's 12z NAM and GFS are actually in relative agreement in keeping the surface low back...way back across the southern or even southwestern TX panhandle at 18z!! As a matter of fact there is now a general consenus in the primary surface low only moving to near the Childress, Wichita Falls vicinity with a dryline extending southward and an east-west warm front in the vicinity of the Red River at 00z, with the cold front diving south through the panhandle...all setting up a classic triple-point warm sector possibly as far west as Wichita Falls on south. This is considerably further west than the E/NE of DFW and Arklatex region. Concerning instability models indicate a good amount of heating taking place especially dryline/west during the late morning and afternoon hours. It would not be out of the realm of possibilities to have the 850 flow develop more of a southerly component ahead of the dryline in light of the latest developments. If that comes to fruition, and with the backed surface flow, storm motions may be just a tad slower owing to that as well, and may not only be more chaseable but hang out in the warm/moist airmass longer. Interestingly enough, this forecasted setup bears some scary resemblances to the Red River Tornado Outbreak of April 10, 1979. The NWS has a great page on that particular event and Plymouth State Weather Center has an archive of upper-air data going back to the 1950s for anyone interested. Ironically enough, Wichita Falls was hit very hard that evening. A big thing to keep in mind is the huge Nascar venue going on this weekend at the Texas Motor Speedway with Qualifying day set to occur on Friday. People in attendance or headed to that event definitely need to stay tuned to the latest weather situation. All in all a very impressive synoptic set up! Good luck and stay safe to all planning on chasing and all who live in that area.

 

[Bob Schafer]

Is it just me, or.....

Somebody else look at this:

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/images/gfs_ten_030m.gif

Is your reaction also "HUH???????"

 

[SteveCarter]

Going to sit this one out too. To far to drive from South Carolina, given so many uncertainties surrounding this system. Every forecast out seems to be a little different than the previous one, but I'm not as optimistic as I was before. March 28, 2000 had 8 tornadoes...not a HUGE outbreak, but I also don't see a lot of similarities like the SPC apparantly does. Looking at the latest models, I DO think there will be some tornadoes, but in a localized area, and maybe even towards eveing, so........staying home on this one. May head out Saturday though into sGeorgia and sAlabama towards the Fla penisula. Good luck to all that head out tomorrow!

 

[Jeff Snyder]

Is it just me, or.....

Somebody else look at this:

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/images/gfs_ten_030m.gif

Is your reaction also "HUH???????"

LOL Nope, wouldn't surprise me... The NCEP models (NAM and GFS) have had poor run-to-run consistency in terms of the location of the surface low. All that said, I don't think I've ever seen a model forecast a surface low to be >1000 miles south of a forecast not more than 24 hours prior.

Actually, I would be surprised if the primary sfc low was that far south, and the model consensus seems to be for a sfc low N or NW of Forth Worth by 0z. The 18z NAM shows the sfc low S of Vernon TX (west of SPS), by 0z. It also shows widespread and persistent precipitation across most of eastern and northeastern Texas throughout the day. For some reason, 3-30-07 keeps coming to mind as I keep seeing this solution (strong shear, but widespread convection prohibits destabilization -- BUST).

EDIT: After looking at everything, I'm starting to prefer the dryline area, from near LTS to SPS and southward. The last several model runs (GFS and NAM) have indicated persistent precip in northeastern TX throughout the afternoon. I don't want to go southeast of Dallas (S of I20), and I'm not sure how much areas N of I20 will destabilize. In addition, forecast hodographs indicate the dreaded S-shaped hodograph in the 0-4km layer. For example, some forecast hodographs show the majority of the SRH in the 0-1km layer, with almost no streamwise vorticity in the 1-4km layer (nearly all cross-wise vorticity). Farther west, the hodographs are forecast to be more straight-line, but I'll take that over an s-shaped hodograph... My experience tells me that S-shaped hodographs favor cyclonic and anticyclonic supercells, but with mesocyclones (and mesoanticyclones) that are relatively short-lived. Moisture isn't as good across western North TX and southwestern OK, but cold mid-level temperatures yield a sounding / thermal profile that looks very similar to many of the "cold-core" events of the past few years. So, with the 12-18z model data, I'm thinking about playing the low-topped supercell threat in the LTS to SPS areas now (as opposed to the warm front / LLJ threat area in eastern TX).

 

[matt patterson]

I find it interesting that all the models (00z RUC and 00z NAM) are pulling a lot more quality moisture into the C/NW part of TX tomorrow.. and shunting overall return in NE TX... anyone have thoughts on this...Maybe the system is slowing down????

 

[Reed Timmer]

WOW the 00z WRF looks very favorable for tornadoes in N TX tomorrow...it's very similar to last night's run, with LLJ further west near the dryline at 00z...continuous 40 kt southerly 850 mb flow coincident with the instability axis.

I definitely like the more circular 850 mb low with this run...the diagonally-oriented, peanut-shaped low of the 12z run was trash.

I also see no similarity with March 28, 2000, except maybe after 00z when the LLJ kicked in. The 00z analysis that day had very weak low-level flow, even at the core of the LLJ. I bet the 03z analysis was MUCH different.

Good luck all.

 

[Jim Bishop]

I'm still planning on playing the dryline for tomorrow. The WRF shows convection firing by 00z across Central/North Central Texas somewhere between Waco and Dallas near or a little to the west of I-35. The 850mb winds even look more backed directly in front of the dryline too, so I'm more optimistic about tornado potential.

 

[Trey Atterbury]

I'm still planning on playing the dryline for tomorrow. The WRF shows convection firing by 00z across Central/North Central Texas somewhere between Waco and Dallas near or a little to the west of I-35. The 850mb winds even look more backed directly in front of the dryline too, so I'm more optimistic about tornado potential.

Im also going to stay around the dryline. Starting around Gainesville. Good road options going all directions. Good luck to everyone going out tomorrow and stay safe!

 

[afischer]

Looking at the new NAM, I still have the same concerns that the GFS has been giving for days. It looks like a corridor of destabilization will occur ahead of the dryline in the wake of the morning/early afternoon stuff... but it still seems like the 850mb flow wants to veer atop the dryline. Thus the forecast is for dewpoints falling off vertically rather than a nice deep moist layer, which won't bode as well for strong boundary layer destabilization. I'm sure some nice supercells will pop on the dryline west and southwest of DFW tomorrow afternoon as the upper wave slams into the area. However, I'm finding it hard to ascertain just how good the low-level shear will be with these storms. The 1km SRH will probably be do-able but it still doesn't look strongly favorable to me, with hodographs on the small side. The better 1km agl flow and stronger low-level shear appears to be forecast farther east in the "grunge." Of course, this is taking the model at face value, so who knows. If the LLJ ends up being a little more brisk and less veered just ahead of the dryline (so that surface-based storms and strong low-level shear are definitively co-located), I'd be pretty excited for some tornadoes.

 

[Jason A.C. Brock]

I dont like all the convection out west and it seems to still be growing and building south. That could give us a crapvection chase tomorrow but if it can somehow clear off behind all the mess we could be in business. I am still thinking we may see the moderate risk pulled even jsut slightly West perhaps even as far as here in Wichita Falls which would make the area along U.S. 287 from Wichita Falls to Forth Worth certainly worth watching. Lots of good roads off 287 also except you get into some hills from Bowie to Fort Worth and to the South on into areas like Jack Young Palo Pinto Parker Counties. This is still better chase terrain however than SE OK. If things do turn out to verify for areas further East as advertised the area around Paris Texas actually isnt too bad for chasing at all. I do intend to stay out of the DFW metro if possible but now that I said that ill find myself there. I really hope this thing slows down and gives us some chasing NW and W of the DFW area tho.
Its looking less likely due to the convection out West but if I wake up in the morning to even partially clear skies and we have made to to 55-60 dews or more and the surface low is near Childress.....let the games begin.
This will actually be a rather neat scenario to watch play out tomorrow for those armchair chasing at work etc. The upperlow back to the NW interacting with what moisture the surface low throws up its way will be interesting. NW Oklahoma will be a very raw place to be on Saturday with temps close to 50 and winds close to 40. Most of Texhoma will be for that matter.
I am also wondering if we may see an outflow boundary setup tomorrow as well....who knows where....or will this all just kinda be merged together along with the dryline and or warmfront.....I guess anyones guess is as good as anyones

 

[Angie Norris]

The more I look and think about it, northwest TX looks like the place to be tomorrow. Moisture is an issue, as it looks like Tds will be in the upper 50s for the most part, and the lack of surface warming seriously worries me. I think any leftover cloud cover from convection tonight will further inhibit warming as well. I'll probably be playing the dryline/triple point area (thinking Wichita Falls for starters and adjust eastward as needed).
Good luck and safe hunting to all tomorrow!!!

 

[Tim Marshall]

TARGET: SEYMOUR-WICHITA FALLS, TX TIME OF DEPARTURE: 10 AM. A classic tornado setup is underway today. It is all coming together from great deep layer shear, to ample surface moisture, to a formidable dry punch, and perfect juxtaposition of narrow jets. It is hard to contain the excitement as it looks so good on paper. Yes, I was glad to see there wasn't a squall line to Del Rio this morning. The MCS over OK doesn't bother me as it will just enhance the warm front across the Red River. So what could go wrong today? For one thing, storms will be many and be fast moving. The Red River will pose a significant barrier to cross. My strategy is to stay in TX and pick off the storms as they come to me. I will play north of the dryline bulge and keep my options open about the warm front/triple point or heading south to I-20. The Dallas area will be under the gun later this evening and I don't want to miss that. There are thousands of RV's at Nascar. Large screens have been erected at the raceway. Folks will be crowding the stands tonight as a movie will be shown paying tribute to the late Dale Earnhardt -just about the time baseball hail could be falling. Be careful. TM

 

[Mikey Gribble]

I have just started to glance things over, so I don't have much of an opinion yet. I am 90% sure I won't be chasing today. I just don't think I could make it to my target in time considering that I can't leave ICT until around 10. There is that 10% chance I may pull the trigger at the last minute though. Anyways, if anybody wants any nowcasting help I will probably be keeping a close eye on things after 10AM, assuming I don't chase. Send me an email or a PM if I can help. [email protected]
Radar, WV imagery, and WRF precip. graphics all indicating that we have a good shot at getting some insolation over the warm sector. I am definitely more optimistic about that this morning. Mid to upper 60 dewpoints well on shore already. Last night's CRP sounding shows that moisture along the coast is plenty deep. RUC does have LLJ veering more than the NAM. I'm not a fan of the RUC though and I'm not buying it. Regardless, shear is definitely not going to be a problem. I would setup half way between Fairfield and Lufkin. I think you could pick up a storm fairly close to there later this afternoon and follow it NE as it moves intot the stronger low-level shear. Do that, and I think you're golden. Good luck to everybody who heads out today. I think you got a good shot at a couple tornadoes.

 

[Evan Stubbart]

I'm heading out now to get some work done in Graham, TX. My plan is to target a box around Wichita Falls down to Graham and ride the storms back towards the DFW area. I'm a bit worried about the cloud cover this morning, but we'll give it a shot. I can't pass up an opty like this so close to home. Good luck to all!