3/27 FCST: KS/OK/TX

[Jeff Snyder]

I thought I would open this thread up since it appears that things MAY be active across the area Saturday...

Looking at the 0z Thurs ETA run, things don't look very promising across OK and surrounding states for Saturday. I mean, the greatest instability is across western OK, while the best low-level shear is removed to the east of the instability, into eastern OK. Wind structure across the area is also unfavorable...

HOWEVER, the 0z Thurs GFS is much more promising! The trough is progged to remain open and progressive through the day, even taking on a slight negative tilt at the upper levels. Surface moisture is progged to be plentiful, and the jet structures across the area yield quite nice shear profiles. From this GFS run, I could see there being a risk of a significant severe weather event across the OK/south KS/north TX. One of the cons I see right now is the fact that the dryline/front is progged to remain west of the area... However, if there is a some trigger mechanism around to initiate convection, things could be quite nice!

Jeff
KC0HJX
www.tornadocentral.com

 

[Phillip Hurlbut]

Saturday looks to be somewhat promising in the NW OK/SW KS area. The new Eta run (not sure what time) has CAPE values over 2500 j/kg for an area around Alva, OK / Medicine Lodge, KS. The shear doesn't look too bad, looks like 850 mb winds will be between 30 and 40 kts in that area. The only thing that doesn't look great is the trough at 500 mb. It's becoming more positively tilted as time goes on (at least thats what I'm getting from the Eta). So we'll see! I'm up for chasing this weekend. Something to get the bad taste of the March 4th high risk squall line out of my mouth! If I had to pick a target right now, I'd say Hardtner, KS.

 

[Tony Laubach]

Leaving Des Moines for Kansas Tonight

Several of us are bailing from the Severe Storms and Doppler Radar Conference in Des Moines to head down to Topeka/Wichita tonight to get ready for what hopefully will be a good start to my season! Forecasting has been underway between talks to come to the desicion that it may be worth while! Stay tuned to my website as this event further unfolds.

[Broken External Image]:http://www.tornadoeskick.com/images/040326b.jpg

 

[Jeff Snyder]

I surprised this thread has been so quiet. With model solutions, it looks like there could be some significant supercells in ICT to SPS tomorrow. THe ETA seems to be coming in line with the GFS in showing stronger flow at almost all levels, compared to previous runs. The trough is forecast to take on a negative tilt tomorrow, and the area will be in the left-front exit zone of a strong jet stream diving down the backside of the trough. All models forecast at least moderate instability (CAPES ~2000 and LIs near -7) and deep layer shear... I still think we'll end up w/ a mdt risk once it appears that this instability will actually develop as forecast...

One of my concerns regards low-level shear. Both models forecast the 850mb jet axis to be east of I-44 by Sat afternoon and evening, with many areas in western OK (primarily northwestern OK) having relatively weak low-level flow, which decreases the low-level shear across that area. This may be negated, however, by winds backing more-than-model-forecast to the east of the subsynoptic low progged to develop from near Shamrock into sw OK...

I am no longer too concerned about squall line development immediately. None of the models I've looked at really forecast UVVs that are that strong. Yes, 500/700UVVs across the aarea by tomorrow late afternoon will be decent, but nothing that would denote, to me at least, a strongly-forced squall line. The speed of the cold front cruising on down through KS may be an issue for those in KS, but I don't really see it being an issue tomorrow afternoon or early evening for those chasing in OK or northern TX....

Jeff

 

[George Flickinger]

The 18z MesoEta is suggesting that a supercell could blow up in SW Oklahoma ahead of the dry line Saturday afternoon. Wind profiles look favorable for rotation. Surface temps could be 85-90 near the dry line toward Altus....I'll head from Tulsa to OKC by late morning tomorrow, and decide from there later.

 

[Shane Adams]

After my brief perusing of models, I'm likely headed to NW Oklahoma tomorrow. Target town as of now looks like the Enid, OK area. Looks like the ETA is being strangely stingy with precip by 0Z, as there is squat anywhere in OK by 7pm tomorrow. I don't buy it. The CAPE is there, the moisture is there (and it appears deep enough). Tonight's convection through tomorrow morning will be a big player I think. Basically gonna get up early and start the satellite loops/WV imagery/surface obs.

UVV spikes stacked nicely throughout NW/Central OK between 18-0Z. I think there's a reason for that. But as I mentioned, I just looked very briefly to get some idea so I'd have something to answer with at the party in a short while :lol:

 

[Scott Roberts]

If I were chasing, I'd be heading southwest from ICT. But I'll be handling our chasers in the ICT area and points west, so won't be able to go south where it looks like the show will be. It'll be interesting to see how the ongoing showers in central Kansas stabilize things, and whether we clear out soon enough to get things back on the unstable side.

Scott Roberts, Chase Coordinator
KWCH TV-12 Wichita

personal chasing site: www.ksstorm.info

 

[Kevin Scharfenberg]

Short version: A few supercells will develop along the dryline in Oklahoma, but the atmosphere will not be "prime" for a major tornado event. Storm mode will tend toward quasi-linear/MCS within a few hours of initiation.

Long version: Tonight, the vort max over Arizona analyzed at 00Z has started moving into west central NM. As this approaches the plains overnight and the LLJ kicks up even more, I'd expect the convection over northwest OK and southwest KS to increase in coverage and intensity.

The 00Z eta suggests the system may come out in at least two pieces tomorrow, with this lead vort max now entering NM passing through Kansas during the morning. That would cause the low-level winds to veer somewhat with time, and clouds and precipitation to continue in northern OK and KS during the morning.

The target area during midday will briefly come under the influence of subsidence after the first vort max passes. Meanwhile, farther west, the dryline will finally begin moving as the stronger upper winds approach and deep mixing west of the dryline kicks in. So, I think there will be a narrow north-south zone of clearing ahead of the advancing dryline and behind the retreating lead vort max. The ageostrophic forcing will help the low-level winds to back again later in the afternoon.

Finally, very strong forcing for upward motion will coincide with the dryline advancing into the strong low level jet and deep moisture during the evening over western Oklahoma. New initiation is very likely, and the most interesting location may be near where the dryline intersects any leftover boundaries between the rain-cooled air to the north and the less-disturbed air to the south. Deep shear profiles will be good to very good. As for tornado risk, the 0-1 km helicity will be strongly dependent on the spacing between the morning vort max and the main vort max. Static stability in the boundary layer will be a little weak, with most of the positive area in the modified/forecast soundings progged to be above the capping inversion.

So, the risk for significant tornadoes doesn't look too high to me right now. The forcing should be strong enough to force a squall line or MCS as the dryline moves into central Oklahoma.

 

[Chris C Sanner]

My initial target is probably going to be in the Altus area. Something tells me to stay south for this one. I'm hoping for a Tornadic Supercell (of course a supercell would be fine in itself) for the day/evening then for the night a nice squall line with tons of lightning. If that situation comes true, I'm gonna have 40-50 great images from tomorow.

Right now I'm in a wait and see on tonights/tommorow mornings convection and see where any boundaries are at. Give or take, I might play one of them tomorrow.

Anxiously awaiting storm chase #2 for 2004.....

 

[Lance Maxwell]

SPC

Well, SPC is staying conservative for the 6z outlook......but my money is on them issuing a moderate risk for the 12z outlook. I tend to agree with their tornado potential (I was thinking anywhere between 5-10 percent) but I disagree with their thoughts on the chance of severe weather tomorrow.

 

[Aaron Kennedy]

I wanna see some clearing... I agree with Kevin that it doesn't look like a great tornado day, but it is a weekend, and it is a good enough excuse for me to go out. Right now I'mma target the dryline... somwhere from SW Ok up to I40. Key is to be there as soon as initiation occurs...

Good luck to all!

Aaron

 

[Jeff Snyder]

I was quite surprised that the SPC maintained the Slight risk for tomorrow... I mean, looking at the probabilties alone, I don't think I've ever seen slt risk for 5%, 35%, 35% probs. At any rate, I've been worried all week about that high on the east coast, which is giving much of the Gulf easterly winds... So we end up with modified continental air rather than true mT air (or true tropical in the least)... Now... check out http://www.wxcaster2.com/CENTRAL_ETA212_SV...HSWEAT_21HR.gif ... That shows the parts of western OK will have CAPES >3000 by afternoon, and SWEAT indices up near 600 (take that for what it's worth...)... I'm not worried about the helicities on that particular image, as they are absolute (environmental) helicities and not storm-relative. If you choose another site for the ETA SRH, you'll see that low-level shear, as measured by helicity, is quite favorable over much of the area ahead of the dry line... I am still thinking the subsynoptic low (if you want to call it that) progged to develop between Shamrock and Altus by 0z tomorrow will locally back winds across portions of western OK, further enhancing low--level shear.

Also, using the Bunkers method, storm motions should be E or ENE at about 35 kts, which is quite reasonable.

So, I'm pretty optimistic about this event right now... The NWS and SPC have seemingly be downplaying the potential (if not downplaying then at least not looking at the potential as favorable), so who knows...

Jeff

 

[Shane Adams]

Perhaps my standards are less than average, but I never really looked at tomorrow (today now) as a 'great' tornado day, just an average one. I expect a few supercells and a few tornadoes somewhere west of 35 tomorrow, and I fully expect to be near at least one of them.

Tomorrow isn't a mega-outbreak, it's just another chase day. And that's usually what the great ones start out being.

 

[Chris C Sanner]

Originally posted by Shane Adams
Perhaps my standards are less than average, but I never really looked at tomorrow (today now) as a 'great' tornado day, just an average one. I expect a few supercells and a few tornadoes somewhere west of 35 tomorrow, and I fully expect to be near at least one of them.

Tomorrow isn't a mega-outbreak, it's just another chase day. And that's usually what the great ones start out being.

Amen to that Shane.

After looking at the latest SPC outlook I still like my chances with Altus being a starting point. But that may be too far south to manuever to anything developing up north. So I might try Hobart to give me a fighting chance for anything up north.

 

[Jim Bishop]

Originally posted by Shane Adams
Perhaps my standards are less than average, but I never really looked at tomorrow (today now) as a 'great' tornado day, just an average one. I expect a few supercells and a few tornadoes somewhere west of 35 tomorrow, and I fully expect to be near at least one of them.

I completely agree! This is why there should be a moderatre risk/15% tornado risk for tornadoes in the area mentioned.

Do most chasers seriously look for a tornado outbreak to say the tornado outlook looks good? I'm forecasting supercells with a few tornadoes. For me this means a good chase day. In my opinion, this warrents a moderate risk. I would not be surprised if the new SPC outlook upgrades to moderate.

Good luck everyone!

Jim