3/21/2007 FCST: TX / OK / KS / NE / IA

[Verne Carlson]

Weds looks like the ‘pick of the litter’ with a 995Mb surface low in sw KS, Tds in the low 60s up into OK and +60Kt divergent SW flow overhead at 500Mb. The trend on the GFS is to neg tilt the trough on this day into Thurs, further increasing the divergence. GFS breaks out precip in central OK nicely. Weds looks like a 'must chase' day.

 

[BrandonWhittington]

A little early, but what the heck. Latest GFS is exploding precip and thunderstorms in the Eastern TX and OK Panhandle. I have noticed that with each run, GFS is deepening the low and is becoming more negitive tilted. If everything stays the same and models are correct, major severe weather might be upon us on Tues and Wed of next week. Moisture levels are also expected to rebound nicely and there will be plenty of time for moisture to make it up this far north. Wed is the Pick of the day. On the other hand, systems like this, storms seem to fire and be more isolated the day before the main storm system arrives. Either Tues or Wed are looking good in the Panhandles.

 

[Jim Tang]

Verne,

Do you mean the 21st and the 22nd?

(might as well post all my thoughts in this thread tho)

I think the dryline will remain capped on the 20th, and even if a storm does form, deep layer shear will be marginal at best.

On the 21st, an initial impulse which swings around the digging longwave trough will move across the area. We could use some deeper moisture, but overall the setup looks pretty impressive with possible supercells developing along the dryline and propagating east at pretty chaseable motions.

On the 22nd, the longwave trough will amplify. We'll see how much it does, because if it amplifies too much 500mb winds will turn southerly and we get squall line vs. supercells. One thing seems likely (especially if the longwave amplifies over the Plains rather than over the Mississippi Valley) and that is there will deeper moisture.

Interestingly, the European model cuts the longwave off over the Desert SW, and the GFS Ensembles are divided over this issue. So this threat is not etched in stone yet.

 

[Ray Walker]

I think the 21st will be the best day out of any of them. Western Oklahoma and far southern kansas have my eye right now. Also the eastern texas panhandle could be in the playing cards if this thing slows down any at all. However I think storms will form in the far eastern texas panhandle and far NW Oklahoma on into Southern Kansas and then move NE at 30 to 35mph, (much better thank 45 to 55mph lol!!!). Supercells seem likely with large hail and tornadoes. The 22nd is kind of a wild card right now. Anywere from SW Oklahoma on east into SE oklahoma will be possible targets along with northern Texas. However like Jim mentioned if 500mb winds do not cooperate then a squal line looks more likely for Thursday.

 

[Mike Hollingshead]

The gfs's ways remind me a lot of the Feb 23-24 event. That time from waaaay out it showed it around the 23-24 for the central plains, then it started to jump around and be less appealing. Then at about this same distance out the 18z run reverted back to close to what it had shown the whole time. Well check out today's 18z run of the gfs, it just flopped back closer to where it had been, and it's a lot more similar to the ecmwf as far as wanting to bring the big upper low out as a whole a bit later.

 

[Michael O'Keeffe]

I agree with Mike I just checked out the latest GFS and the low is ejected into the Plains on Friday and is quite strong. The low seems to be placed on the KS/OK border.

 

[Brian Stertz]

It should be "go time" Wed.

I think the setup for Wed. looks very good for the chase...I am liking the C/SC Kansas area more and more...quite a few favorable parameters seem to be overlapped there...strong 700mb wave, triple pt. & SE quad of sfc low, more backed winds, strongest sfc/850mb convergence, enhanced upper divergence, etc. I will probably favor a position between Great Bend and Med. Lodge for the main action zone Wed. afternoon & towards the I-135 corridor by Wed. evening. Things should become more elevated the further east the storms get Wed. night.

 

[Dick McGowan]

Last night's run didn't look to good to me last night. There didn't seem to be very much convergence near the dryline. The 12z run looks a lot better, still aways out, but Western Kansas has got my attention. Guess we'll wait and see.

 

[Jim Bishop]

The GFS has trended slightly further north with the location of the surface low (Northeast Colorado/Northwest Kansas), which is in better agreement with the European. Therefore , next Wed looks more certain for a severe weather event, imo, based on that alone.

Regardless the last few runs of the GFS have been pretty concistent, suggesting supercells firing along the dryline from West Texas north to the Texas Panhandle into Western Kansas. The 30-40 knot southerly 850mb flow above 15-20 knot southeast surface winds, coupled with dewpoints in the upper 50s to lower 60s and 1000-1500 CAPE, suggests the potential for tornadic supercells.

Too bad for me this occurs in the middle of a work week...

 

[Mikey Gribble]

I am pretty much in agreement with Jim, but I still have a few concerns. Mid level SR winds could be better for this time of year. I am also still concerned about good moisture making it all the way up to KS. If moisture is going to be a problem in KS moving South down the dryline would be my play. I do love the strong inflow level winds though. It is still way too far out to get into any specifics, but I am thinking it is more than likely going to be a chase day.

 

[matt patterson]

This "Event" is still a long ways off, but i cant help thinking that with all the precip that is forecasted all week long, that we may have trouble getting instabilities in place for large scale severe weather in KS/OK/TX..... Not to be pessimistic just making an observation...

we shall see...

 

[Kenny Drake]

I feel the moisture return problem would be solved quite easily if the surface low ends up forming more south, which in return will give a much shorter distance for the gulf moisture to advect. I'm thinking this system will have a definite spring like setup. Those to the north will probably want to hug the warm front. The CAP will be a bigger problem farther south with warmer and probably drier 850mb winds. Current OK Mesonet readings show Tds just after peak heating on Saturday in the mid to upper 40s. After looking at the 12Z NAM runs this moisture should hold in place. However, a cold front is progged to stall out somewhere over the state on Monday. Hopefully that front stays farther north. This will allow some 850mb moisture advection through Monday, before the LLJ really kicks in on Tuesday.

 

[Jason Boggs]

I honestly think this will be the pick day to chase this week. The gulf is WIDE OPEN so I don't think Td of high 50's to low 60's will be a problem in the target area. Obviously it's still a long ways out and many things can and will change. If I had to pick a target area right now I would have to go with the eastern part of the OK panhandle near Woodward. I think there will be a fairly significant warm layer aloft to deal with if one targets too far to the S or SW. Any further N and I think the moisture won't be quite as good for surface based convection. Looking for outflow boundaries from previous convection may end up being a key player to get that extra low level helicity for the storm to work with. Anyway, I'm sure things will be interesting and I imagine my target area will change by Wednesday.

 

[BrandonWhittington]

I totally agree with Jason.......Dew points are already in the upper 40s in western, OK and Eastern panhandles. The gulf will be open for a while now and dew points should be in the mid 60s on Wed. Systems like this seem to be a little stronger than models indicate. My gut feeling is to be somewhere in Beaver County. Like Jason, from Beaver to Woodward Looks good. I just feel that being closer to the Warm Front (if present) will be best. I know its early, but need to get ready for Wed.

 

[Jay McCoy]

I wont rehash jasons post except to say the GFS is trending a bit further south today which would move the best dynamics under a pretty strong lid. Finding the right area with enough energy to get through the cap and still have enough moisture might get tricky. The big player will be where the stalled front ends up sitting. Still too early to even think of a target but I do think wednsesday will be the choice day for this area. Thursday might be good a bit further east towards OKC. Hey I am off work.. I am ready for a few days of chasing.