2013-05-31 FCST: KS, OK, MO, IL

[Brian McKibben]

Well... nobody is excited about this day yet either. So, while I wait for AERMOD to run, I figured I would get this one going too.

SPC has 30% risk from Central OK all the way to Western IL. I think the play in Central OK looks particularly interesting. If we can get the triple point to set up in the area, things could become quite explosive.

Both GFS and NAM puts Central OK in the Right Entrance region of the 500 hPa jet streak. Both have the area progged with 3000-4000 j/kg of CAPE. Directional shear is great too. Here is the 3km EHI from the GFS. All I can say is yikes!!! I am pretty sure that would be about a 14 (if the scale didn't stop). Then I pull up a sounding and it looks just as impressive.

I will be keeping an eye on this one for sure. As meteorologist and chasers try to let everyone know of the possible volatile weather.

 

[chrisbray]

The soundings aren't quite as good in Illinois with winds backing a bit once you get to above the 500 level, and the instability isn't progged to be as great, but I think Illinois will be in play, great 850 and 500 wind speeds and surface to 500 crossovers. And, it's my anniversary so I can guarantee something big will happen since I won't be available to chase, just like June 7 2008 when the big tornado went through south of Chicagoland, because I was on my honeymoon

 

[Logan Karsten]

I am surprised at the lack of posts on this day. Perhaps it's because everyone already knows/sees what could potentially occur. I am also quite surprised SPC's day 2 wasn't upgraded to a moderate risk for central OK given the insane ramp of parameters tomorrow afternoon. However, they may upgrade to a moderate this afternoon with the new day 2 outlook. Scary situation across the OKC metro tomorrow afternoon/evening. 500 flow will be west-southwest, with backed surface winds and a triple point just west/northwest of the OKC metro area. The low-level jet will be ramping up by early evening, so if anything is discrete at that time, I would expect continued risks for strong/violent tornadoes. All models initialize convection mid-late afternoon just west of the OKC metro area along the dryline/triple point. Given the nature of the shear and low-level flow, would not be surprised to see at least one strong/violent tornado somewhere in Central Oklahoma tomorrow afternoon. I would say wait to see some more model runs to confirm these fears, but the models have been extremely consistent showing this setup now. Everyone stay safe tomorrow, and I truly hope anything that does occur stays out of the OKC metro area, but it seems like any time the parameters come together across the metro area, someone gets hit bad.... I hope I am wrong and things stay in rural countryside.....

 

[Lee Smith-Whaley]

Just a heads up to people to be careful in SE KS, especially around the Coffeyville, and the Parsons areas. Lots of flooding going on, including on the highways. If I end up chasing, I'll probably end up starting out around Coffeyville. The road network is pretty decent down there, so if storms go up to the west in the more favorable environment I can adjust accordingly. The dewpoints look extremely favorable, not to mention the backed surface winds.

 

[Eric Bucsela]

I am surprised at the lack of posts on this day. Perhaps it's because everyone already knows/sees what could potentially occur. I am also quite surprised SPC's day 2 wasn't upgraded to a moderate risk for central OK given the insane ramp of parameters tomorrow afternoon. However, they may upgrade to a moderate this afternoon with the new day 2 outlook. Scary situation across the OKC metro tomorrow afternoon/evening. 500 flow will be west-southwest, with backed surface winds and a triple point just west/northwest of the OKC metro area. The low-level jet will be ramping up by early evening, so if anything is discrete at that time, I would expect continued risks for strong/violent tornadoes. All models initialize convection mid-late afternoon just west of the OKC metro area along the dryline/triple point. Given the nature of the shear and low-level flow, would not be surprised to see at least one strong/violent tornado somewhere in Central Oklahoma tomorrow afternoon. I would say wait to see some more model runs to confirm these fears, but the models have been extremely consistent showing this setup now. Everyone stay safe tomorrow, and I truly hope anything that does occur stays out of the OKC metro area, but it seems like any time the parameters come together across the metro area, someone gets hit bad.... I hope I am wrong and things stay in rural countryside.....

Roger Edwards' 06z Day-1 SPC outlook does little to assuage Logan's concerns here that a dangerous situation could develop near the OKC metro area on Friday. The 00z runs of NAM and GFS show winds backing dramatically in central/southern OK during the late afternoon in response to the deepening surface low, with impressive hodos. All this in an environment of CAPE potentially above 5000 J/kg. I suppose it's possible that conditions could turn out less than expected (e.g. as on Wed and Thu), but right now the params look pretty impressive. Hopefully any big torns - if they form - will track through slightly more rural areas, maybe south of the metro area, depending on where the triple point sets up.

 

[Jeff House]

Very first post of this thread has key info. Today/Friday Oklahoma is in the right entrance (right rear) of the jet max departing Kansas. Yesterday/Thursday OK was in the right exit (right front) which is subsidence. Today OK has rising motion from jet streak. Plus, new jetlet is curved coming in from Colorado. On curved jet streaks, entire front/exit is lift. One could argue subtle kissing jets over Oklahoma. Sounds exciting for storm chasing, but not good for the public.

06Z SPC also notes slightly falling heights (700/500/etc.) after mid-afternoon today; yesterday was rising. Surface to 850 winds, incl. 925, back after 21z today. They did not really back yesterday. Everything from surface to upper levels is more bullish for chasers today. If you got minute, post a little something on social media for your friends in Oklahoma.

Finally looks like a boundary is just north of I-44, parallel to the Interstate, on visible imagery these first few frames of daylight. It was slowly sinking south at sunrise. It should stop around midday as south winds increase. Also that upstream shortwave out of Colorado will help put the brakes on the boundary as surface-850 winds back this afternoon. Supercells may unfortunately impact OKC Metro right on boundary intersection. First 1-2 sups south of intersection may be more isolated for chasing. Figure 3rd and 4th south could suffer similar struggles as the end of the line yesterday/Thursday. That being said, today/Friday will be a tornado day on the supercells closer to the boundary intersection. Good luck, think of OKC, and be safe.

CORRECTION: I-44 is a gravity wave, also bullish severe. However main OFB is south of I-40, not good for OKC public. I prefer 06Z SPC over 13Z still.

 

[Jesse Risley]

The soundings aren't quite as good in Illinois with winds backing a bit once you get to above the 500 level, and the instability isn't progged to be as great, but I think Illinois will be in play, great 850 and 500 wind speeds and surface to 500 crossovers. And, it's my anniversary so I can guarantee something big will happen since I won't be available to chase, just like June 7 2008 when the big tornado went through south of Chicagoland, because I was on my honeymoon

The southern target proximal to the southern flank of the mid-level jet core's entrance region (OK/SE KS/SW MO/N AR), as it rounds the basal side of that upper low, might be the best bet today, given that several surface boundaries are notable on visible satellite and morning surface observation analyses. However, areas of S/SE MO and SC IL (south of I-70/I-64) have also undergone some destabilization, though the impact of forthcoming cloud debris and convection could help or hinder the risk in this region.

Needless to say, better streamwise vorticity owed to more favorable hodographs appears poised to lie in the southern target today, as wind shear profiles are more parallel to the boundary across the northern region in E MO and SC IL. Some of the model guidance is wanting to maintain initial discrete activity across parts of OK, whereas linear modes appear to prevail in that respect across the I-70 corridor and points south. Nevertheless, I agree that, in respect to the northern target, areas that destabilize and can co-locate with remnant boundaries from earlier convection will need to be watched, as even if initial activity is not discrete across parts of MO and IL, tornadic potential cannot be ruled out given ample 0-1 km shear values that could exacerbate tornadic activity embedded in line segments/MCV tornadoes.

 

[Jennifer Rhoades]

I'm trying to let my friends in Oklahoma know about the possible tornado threat today? What time is possible ignition in Central time? I have friends & family near Mustang, ok & Moore ok. Some without shelters who need to plan ahead. I'm not a chaser, just girl who grew up in Oklahoma who always is weather alert. Want all to be safe since many have to plan ahead to find a shelter. Any info would be GREAT!
Please let me know if I'm breaking the rules & I will no longer do this again. Thank you.

 

[Warren Faidley]

I'm trying to let my friends in Oklahoma know about the possible tornado threat today? What time is possible ignition in Central time? I have friends & family near Mustang, ok & Moore ok. Some without shelters who need to plan ahead. I'm not a chaser, just girl who grew up in Oklahoma who always is weather alert. Want all to be safe since many have to plan ahead to find a shelter. Any info would be GREAT!
Please let me know if I'm breaking the rules & I will no longer do this again. Thank you.

Best bet is to tell them to go buy a weather radio. That way, they will know when a watch is issued. Ignition time is not always a given and severe weather (especially on highly unstable days) can form anytime. Trying to plan a day around a specific time is not a good idea, even though the most likely time is after noon.

W.

 

[Adam Atkins]

The warm sector is on the warm side of the jet, much stronger capping today (101 convective temp in 12z OUN sounding) so initiation will likely be later today than yesterday. Vertical wind profiles are quite similar but Td's are higher...thus CAPE will be substantial, over 4,500 under the sun. The longer storms can hold off from initiating, the better chance of them becoming tornadic because winds back in the low levels towards sundown. Deep layer shear is adequate for sustained supercells (like yesterday), but low level shear isn't great (like yesterday), meaning either an outflow boundary or low level instability/stretching will have to compensate. Just west of OKC looks to be a good spot for initiation and the metro will again be in the bullseye.

 

[JamesCaruso]

Jennifer, I am traveling home from my chase vacation today and haven't done any in-depth analysis. Others can surely advise you better. But in case no one responds, I wanted to at least be able to pass along SPC's expected timeframe per their 8AM outlook, which noted a 4-5PM initiation. But stuff has seemed to go up early all week....


Sent from my iPad using Tapatalk HD

 

[Jennifer Rhoades]

I was wanting to know the earliest possible ignition. Sorry for the confusion. I told them anytime after one to be near a shelter and ready. They are all paying attention to the weather.

 

[Rob Gardner]

It`s very puzzling to me that the SPC upgraded to 15% and hatched area for tornadoes without high risk, I don`t think I`ve ever seen 15% be moderate risk before. I hope the OKC area takes this setup very seriously. If things play out right it could be a very short window of warning between initiation and touch down.

 

[Jacob Ferden]

It`s very puzzling to me that the SPC upgraded to 15% and hatched area for tornadoes without high risk, I don`t think I`ve ever seen 15% be moderate risk before. I hope the OKC area takes this setup very seriously. If things play out right it could be a very short window of warning between initiation and touch down.

15% hatched tor probs are moderate risk criteria...already used on April 17 and May 29, to name at least two days this year.

 

[Marcus Diaz]

I'm pretty sure it has to be a 30% or higher tornado probs for a High Risk. 15% tor and 45% hail is what's warranting today's MDT. I think storm coverage is what's holding back SPC's upgrade. There may be only a couple of monster cells today doing all the work. I'd understand a HIGH risk if there was good confidence that several supercells were probable today.