4/24/07 FCST: KS/OK/TX/MO/NE/IA/IL

[SteveCarter]

Well, data pouring in now is showing a fairly 'high" risk here(OK/TX/KS) on tuesday, but I'm still a little concerned with the timing issues. IMHO...I see a GREAT set-up regardless of timing, but since I'm in South Carolina, this is a LONG drive, but probably worth it, just need a better grip on the timing. Shear profiles are awesome, instability ok. By only concern, so far..lol, is driving 1200 miles, and then waiting until dark to "see" anything, but more fining tuning is on the horizon. All in all tho....this could be a high risk by then??

 

[Donald Giuliano]

Have been focusing on Saturday and not paying too much attention to Tuesday yet, but after investigating it a bit, I'm very, very impressed. Though not the same type of setup, in terms of magnitude/areal extent of severe weather indicators, it looks comparable to April 26, 1991 or May 4, 2003. There's still a long way to go in terms of what exactly is going to verify, and we all know how the models do with cutoff lows, but I'll see if I can't get the afternoon off that day.

Hey, here's a thought...maybe there's an 8-yr cycle for Oklahoma (91/99/07?) embedded within the 4-yr cycle?

 

[Kenny Drake]

I'm a little surprised that SPC has been fairly confident in placing the highest risk over central OK. The general dryline location between the 00Z and 12Z run displaced the dryline from the eastern TX/OK panhandle to Altus/Lawton and points N and S. Regardless, I think a severe weather outbreak is still on tap beginning Monday and working into Tuesday. Narrowing down a target zone on Tuesday will be highly dependent on any OFBs layed down from Monday night's convection. The gulf remains "unharmed" for the most part as the cold front associated with the current system will likely stall out across central OK. This front will likely retreat northwards later tonight as pressure falls are induced across the TX/OK panhandle in response to another 500mb wave propagating into the SW US. I'm trying not to get overly confident as this is still two days out but everything looks good. The only concern I have at this point will be the amount of instability ahead of the dryline. Due to the relatively close proximity to the upper level low and vortmax overhead clouds could be the primary factor on Tuesday. However, only limited heating will be required to reach convective temperatures and this will likely occur by mid afternoon. Supercells will be likely given the favorable wind profiles and these will likely congeal into a long MCS by mid evening.

I will likely be chasing this event (and tomorrows). Western OK is great for storm chasing and hopefully the current NAM verifies especially with regards to location. As Donald mentioned, cut-off lows can be difficult to forecast as models tend to have issues with them. It seems the models have been overspeeding openwaves more than cut-off lows this spring, so that may be an encouraging sign.

EDIT: This isn't a forecast so I wont make a seperate post for it, but I noticed the wording under SPCs day 3 convective outlook includes "HIGH POTENTIAL..." with regards to severe weather. The only time I see that kind of wording is when the outlook includes a high risk. I'd say there is a good chance that Tuesday will be a HIGH risk day as long as the current model forecasts hold together.

 

[Ray Walker]

I really dont think storm mostions are going to be nasty. Storms should be moving anywere from 35 to 45mph on tuesday. I havent looked at models a whole lot today due to resting up from yesterdays 900mile round trip. But I am encouraged by the day 3 outlook

 

[Jeff Snyder]

When was the last time we saw back-to-back significant supercell and/or tornado events in Oklahoma? Heck, for the most part, I don't think OK has seen a multiple-tornadic-supercell day since 10-9-01. Yes, there have been a few days (such as 5-8-03) that saw a couple of significant tornadic supercells in the state. However, I don't think the state has seen what I'd call a "tornado outbreak" since that fall 2001 event. Oh well.

The shear profiles for Tuesday look pretty good, as does the low-level moisture. It's still a little early to say much, but I agree with the MDT on the SWODY3. Forecast soundings from 00z/23 NAM run indicates the environment east of the dryline in central and eastern OK, northcentral TX, and eastern KS looks primed for tornadic supercells Tuesday. CAPE isn't remarkable by any means, but we may be able to push 3000 j/kg in some areas. Shear profiles look relatively strong as the 500mb jet streak moves into the warm/moist sector. Hodographs do show some slight backing around 3-4km AGL in some areas, but that doesn't concern me too much at this time.

The closest analog I can find is 4-6-06 -- a cut-off 500mb low in northwestern Kansas, with a surface low east-northeast of the upper-level low. The 00z NAM showed the dryline to be east of I35 N of I40 Tuesday, which isn't too far west of the dryline location on 4-6-06. In addition, IIRC, dewpoints on 4-6-06 were in the mid-60s east of the dryline, which again seem similar to what is forecast Tuesday.

--> http://www.spc.noaa.gov/exper/archive/events/060406/index.html

Unfortunately, much of the warm sector busted in regards to tornadoes on 4-6-06 (though there was a multiple-tornado-producing supercell N of I70). I think one of the primary limiting factors on that day was a very narrow and limited instability axis, largely caused by persistent strato-cu across northeastern Oklahoma, southeastern KS, and southwestern MO. At this time, it looks like the instability axis should be wider than was seen on 4-6, which is a good sign.

It's important to remember that the NCEP models have shown a bias to mix the dryline a little too quickly / too far east on days such as what we'll see Tuesday, so I wouldn't be surprised to see the actual dryline end up 75-100 miles west of the current forecast. And, of course, we know how tough cut-off lows aloft can be to forecast, so we shall see.

Right now, I'm thinking a high-end MDT event, though the potential for an upgrade to that is possible. It's still 48hours out, and it still has to deal with potential affects/influences from overnight convection tomorrow and Tuesday morning.

 

[Jim Bishop]

My main concern for this setup is how the GFS shows nearly unidirectional shear between 850&500mb. The WRF shows slightly more veered flow at 500mb, and maybe I"m being too picky. This does resemble May 4, 2003 but further west. If the 12z models continue to show this I may have to take a vacation day and chase.

 

[Chris Sokol]

I have been looking at this all night, and I am not convinced that the area outlined in the Day 2 as Moderate is going to stay where it is...I just don't see the dryline advancing as far East as they are forecasting. I am looking for initiation on a Wichita/Clinton/Altus line. I will most likely head to El Reno or Kingfisher around noon and watch the data from there.

 

[Michael O'Keeffe]

This looks like it could be a big event across KS and OK! Storms are going to initiate early around 12-2pm west of I-135 from Salina down towards Wichita and the storms will quickly become supercelluar and surface-based. Tornadoes will soon follow and the storms move E or NE and move into E KS through the afternoon and evening hours. By about mid-afternoon storms will fire further south in Oklahoma. These storms will be tornadic as well as the move E. As night falls the storms will move into MO and AR with a continued threat for tornadoes. I havent found a target yet, but it may somewhere near the Hutchinson area. Will make a target tomorrow morning.

 

[Kevin Crawmer]

I am interested in playing the warm front of the storm tomorrow...more because of my limited range in chasing than anything else (plus it hasn't received much pub on here yet). The NAM and GFS aren't too consistent on handling the severe threat in the lower Missouri/mid Mississippi River valleys, but the ingredients seem to be in place for some isolated supercells and tornadoes. Coverage-wise it may be a more chaseable situation than in KS/OK to me because I think decision making will be easier on which storm to chase if they aren't blowing up all over the place. Chaseability will not be great in terms of the road network in the I-70 corridor and points just north and south. North of 70 is not bad in MO as far as visibility and a little bit of a N/S and E/W road network. All in all I was a little suprised the SPC was as demonstrative as they were with the hatched area, but I do believe it is warranted after looking at the soundings for COU and STL. It definitely doesn't look like the widespread event that it does out west, but I am confident something will happen in this region.

Now I just need to get the afternoon off...

 

[beaudodson]

A lot of discussion here from the severe weather crowd as well
http://www.stormvista.com/forum/index.php?showtopic=541

It sounds like SPC might upgrade more of Kansas and Missouri into the Moderate Risk tomorrow. This set-up reminds me of last Aprils outbreak - lot of hail north and then tornadoes late morning into the afternoon over a fairly wide warm sector. Illinois should prob also be added to the thread mix. In the past set-ups like this have brought the St Louis and KPAH Forecast Offices some pretty active weather including tornadoes. Wouldn't be surprised if tomorrow ends up a possible high risk day.

Water vapor this morning shows a nice feed from the Pacific pouring into Texas and Oklahoma and a wide band of moisture south all the way into Mississippi and Alabama and back into Texas and the Northwest Gulf of Mexico.

http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?wv_east_enhanced+1

An impressive tongue of higher dew points is also streaming in from the Western and Central Gulf of Mexico
http://twister.sbs.ohio-state.edu/surface/dewpoint.gif (already in the 70s with dew points across extreme Southern Texas)

Impressive widespread high CAPE Values tomorrow
http://www.spc.noaa.gov/exper/sref/gifs/2007042303/SREF_hicape_MEDIAN_MXMN__f045.gif

Interesting also how the SREF paints the large warm sector
http://www.spc.noaa.gov/exper/sref/gifs/2007042303/SREF_03HR_SVR_PROBS__f045.gif

Tuesday Evening Supercell Comp
http://www.spc.noaa.gov/exper/sref/gifs/2007042303/SREF_SUPERCELL__f042.gif

Tornadic Ingredients
http://www.spc.noaa.gov/exper/sref/gifs/2007042303/SREF_prob_combined_sigtor__f042.gif

0-1 Helicity
http://www.spc.noaa.gov/exper/sref/gifs/2007042303/SREF_1KMHEL_SSB_MEDIAN_MXMN__f045.gif

Effective Bulk Shear
http://www.spc.noaa.gov/exper/sref/gifs/2007042303/SREF_ESHR_SSB_MEDIAN_MXMN__f042.gif

Widespread area of 850mb 10 deg dew points
http://www.spc.noaa.gov/exper/sref/gifs/2007042303/SREF_850MB-DWPC_MEAN_SD__f042.gif


Tomorrow looks very active for a large area. Good luck to those who decide to head out to photograph the event. Stay safe!

 

[Jim Bishop]

Well unless the GFS shows a major difference from the 12z WRF, I think I'm gonna head up to Central OK/KS for this one. Looks like a historic tornado outbreak. Only problem is I'm dog tired from the weekend chase and stuck at work 'till 2pm. May have to fly up there for this one curtesy of Discover and rent a car...

 

[Donald Giuliano]

One thing I don't like about Tuesday is that the 850mb low is forecast to have a very round shape to it (typical for a cutoff). I'm not overly fond of these round lows, because it makes the shear very unpredictable, and it often verifies much worse than the models forecast.

That said, I still think this has the potential to be a really bigtime event worthy of a high risk, but one that we may not have a good handle on until the afternoon of, and one that has a high potential for not living up to lofty expectations. I'll certainly be keeping a close eye on it.

 

[Jesse Risley]

MO/IA/IL sector

I think the area along the warm front could be a good play, so I’m targeting east-central MO in the late afternoon hours as well. Moisture should be more than adequate for the warm front play, and deep layer sheer profiles appear favorable for supercell development in the late afternoon hours.

There is one potential fly in the ointment, per the recent SREF, as I see a possibility that the best severe dynamics in this region could remain well south of I-70. The dryline appears poised to reach KEAX by 2000Z, but effective shear MLCAPE values could be somewhat limited by the time convection reaches NE Missouri and Western IL. This is one to watch, but I think things are still a bit far out to get too excited over in this neck of the woods.

 

[Brandon Sullivan]

I will plan on Columbia Mo.. If gas and time were unlimted would definitely be heading to Ok.. Like the 12z nam and 9z sref.. wonder if it will go high risk at 1730.

 

[Jesse Risley]

I will plan on Columbia Mo.. If gas and time were unlimted would definitely be heading to Ok.. Like the 12z nam and 9z sref.. wonder if it will go high risk at 1730.

I'm guessing the high risk may be delayed until things are able to come into better perspective tonight, but I could be wrong. I'm thinking central OK and southern KS are definite hot spots as things materialize, based primarily on the NAM.