04/03/08 FCST: TX / OK / AR / MO

[Tony Laubach]

GFS hinting at an interesting setup on Thursday after quick return from the weekend's system. If the moisture returns as much as the GFS indicates, Thursday could be very interesting.

Models are showing upwards of 3000 CAPE west of OKC by 0z Thursday with good surface flow along the dryline progged to be from roughly west-central Oklahoma southwest through west Texas. Everything seems to want to pool in west-central Oklahoma.

Normally I don't throw out threads this far in advance, but there has been some consistancy with kicking a system into the southern plains during this time frame, and while change could occur run-to-run between now and then, its definitely worth noting Thursday and have it in the back of your mind.

 

[Kevin Crawmer]

Well since I have to work on 3/31 and things will get linear by the time I am off I will focus on Thursday. The GFS has been pretty consistent with taking a low across northern Missouri through the day on Thursday...mainly along the I-70 corridor and drifting north into IL. It appears that there will be some warm front activity in this region during the afternoon hours and then things really get going as it crosses the Mississippi into southern IL before going linear by 06z on Friday. Moisture return will be adequate, surface temps will be sufficient, but there will be a tight gradient here along the warm front (45-60+ degress seperated by 60-80 miles it appears). The GFS is quick with the low and does not strengthen it as much as the ECMWF as per the SPC outlook (I have not looked at the ECMWF...can't find one to go out over 100hrs--help?). There is better L.I. in NE OK, SW MO, and N AR.

My thoughts are storms popping along the warm front during the early to mid afternoon hours in central MO and going MCS to linear as it heads eastward. Storms possible along the cold front with a lot more help from better thermodynamics in these areas. The GFS has things going nuts once it moves into S IL/IN overnight, but I am hoping the ECMWF holds true and slows this down to see more action during the day on Thursday.

I may be able to swing an off day on this one so I am definitely looking at it through optimistic eyes. Thoughts?

 

[Mikey Gribble]

The GFS also has 850mb winds out of the West. I'm not sure I'm buying that, but it definitely isn't good.

 

[Kevin Crawmer]

Well since I was hoping to chase this in the SW MO/NE OK/SE KS/NW AR area I was disappointed to see the models trending towards the more southerly track. I still may head out west if the models can talk me into it (chase partner out there? Need to be back in St. Louis in time for work at 8am on Friday).

Anyways, the mention of discrete supercells, the SPC considering a day 3 moderate, never having chased the dryline in S OK, etc have me considering playing this one.

CAPE values have been going crazy the last few days on this. Most of the heavy precip seems to be focused along the warm front and trailing cold front leaving the warm sector uninhibited of moisture it would seem. Convection from Wednesday will hopefully clear out. If the wind fields come around like mentioned before this set up should have all the makings. I really fear for flooding concerns from the OK area NE into MO/IL.

If you need a chase partner and plan on driving back anywhere along the 44 corridor on Thursday night PM me....I will be happy to meet you anywhere along there.

 

[cdcollura]

Good day all,

Can't chase this one either guys ;-(

SPC already has outlook of 30% across west-central TX to the OK panhandles. 70 - 75 Knot 500 MB flow possible ahead of upper trough crossing the rockies by Thursday (4/3). Looking like a classic dryline setup.

 

[Kevin Crawmer]

I am a bit puzzled as to why the 30% area is so far west. I agree with Alex in that it seems like showtime will be in the I-35 corridor with daytime heating, arrival of the energy, LLJ, etc. The GFS still seems to like a little more of a northern track while the ETA takes things along the Red River Valley. I hope things line up soon since I will need to decide on things by late afternoon tomorrow.

 

[Mark Farnik]

Looking at the latest run of the GFS, several things are interesting to my eye. The latest run of the GFS shows a LI bullseye of -12.5, SBCAPE bulleseye of 2935 j/jkg and MLCAPE bullseye of 2890 j/kg over south central and southwestern Oklahoma at 0z Friday. Taking a quick glance at the ETA model, it depicts a corridor of 3km helicities in excess of 300 m/s2 from near Altus northeast through OKC area and paralleling the Oklahoma Turnpike towards the Tulsa area. Based upon this information, at this point I would tentatively say that initiation will be in southwestern Oklahoma in the Altus/Lawton area in the 0z time frame. This is just a rough estimate given the current information, which is admittedly somewhat murky. Further runs over the next 48 hours should clarify the subtle mesoscale details as we get closer to the event. I'm still a bit concerned about the progged south/southwesterly winds at 850 mb, but since the windfields will likely come around with time, I would have to say as a whole this setup definitely has the potential to be the first High Risk on the plains this year.

 

[Jim Bishop]

This morning's WRF suggests a great setup over Western North Texas/Southwest Oklahoma near the triple point and dryline bulge. With the conditions this model is forecasting I would expect tornadic supercells should the model verify. The GFS from last night is a little more elongated and progressive with the shortwave, but has similarities to the WRF at the surface. It will be interesting to see how things pan out.

 

[BrandonWhittington]

Ill agree that the risk is a little to far west. The panhandles have seen hardly any rainfall this year and the soil moisture is hardly there. I do agree that the dryline will form along the NM and TX border overnight wed, and quickly progress east on the day thursday, Eastern Panhandles to western OK would be the furthest west I would go and that is pushing it. I would say it will hang up in western oklahoma.

The cold front, in my opinion is what is going to be the key question. Depending on how much rainfall Oklahoma gets on Wed is Key it could hurt us or break us.....

I definately plan on chasing thursday, if there is anyone else out there will be out and want a chase partner, let me know......

 

[Bill Tabor]

Barring any atmospheric screwups from Wed night, or major model mistakes I think Thur will be a tornado day. Moisture will return to the Red and perhaps beyond, Sfc low will be positioned near CDS with good lower level flow. Mid level wave will interact by 0z (or likely before).

Current Target: SPS
Forecast: Tornadoes - some strong, initiation - 21z

 

[Kevin Crawmer]

Ill agree that the risk is a little to far west. The panhandles have seen hardly any rainfall this year and the soil moisture is hardly there. I do agree that the dryline will form along the NM and TX border overnight wed, and quickly progress east on the day thursday, Eastern Panhandles to western OK would be the furthest west I would go and that is pushing it. I would say it will hang up in western oklahoma.

The cold front, in my opinion is what is going to be the key question. Depending on how much rainfall Oklahoma gets on Wed is Key it could hurt us or break us.....

I definately plan on chasing thursday, if there is anyone else out there will be out and want a chase partner, let me know......

I wonder if they have the risk a little further west because the models have been slowing the arrival of this system a bit. I agree that the parameters are best between Wichita Falls to Dallas and Northward to OKC and Tulsa....at the moment.

 

[Gabe Garfield]

I wonder if they have the risk a little further west because the models have been slowing the arrival of this system a bit. I agree that the parameters are best between Wichita Falls to Dallas and Northward to OKC and Tulsa....at the moment.

I think that's the reason. The trend has been to slow down the wave, which is the usual trend this far out.

Also, I like the forecast of a slightly longer wave in the upper levels. This should slow the propagation of the shortwave trough (since shorter waves propagate faster) and increase the odds of a favorably timed wave.

Otherwise, things are looking much, much better. I agree with the assessment of the potential severity of this event.

 

[Kevin Crawmer]

Does anyone else have concerns about the environment being too sheared? BRN values in the soundings I have checked in the area are all close to or below 10.

 

[BrandonWhittington]

I dont really think so, shear in my opinion is almost perfect....Just my opinion, it almost reminds me of May 15, 2003....We will see

 

[Gabe Garfield]

I am a bit concerned about the "jet energy" in the northeast U.S. ruining the show for Thursday. With that particular portion of the stream dominating the continental picture, conditions on Thursday are a bit more up in the air (no pun intended).

Two scenarios:
1.) The northeast U.S. system verifies with a weaker intensity, allowing for a favorable timing of the s/w trof to the west.
2.) A secondary jet streak will emanate from the southwest U.S. trough too early (to join up with the northeast U.S. trough) and cause the near-surface flow to veer during the afternoon and evening.

Also, I am a bit concerned about the junk precipitation that is forecast by both models which may end up stabilizing the atmosphere. However, the verification this year seems to be drier than forecast, so I'm slightly more optimistic about this than I would have been in past years.

Obviously, a significant tornado threat could be realized, so it is definitely worth watching. Nevertheless, it is not (yet) the perfect setup.