2021-10-10 EVENT: OK, TX

Jul 17, 2004
381
20
11
63
Piedmont, OK
Hello fellow Stormtrackers! It's been way too long since I last posted on here. the following is what I posted on other social media platforms and thought it's past time I contribute on here.

Most likely one of the best set up's of the entire year expected to unfold across the southern plains; specifically Oklahoma during the late afternoon thru the overnight period for much of Oklahoma, south and east of a line from GAG to PNC on to the DFW area. Currently, deep moisture currently advecting northward from the GOM will firmly be in place by the 23Z time frame, setting the stage for discrete convection to initiate over the east and southeast sections of the TX. PH., close to where the surface low should be located with a 998mb. surface pressure; a fairly respectable system for this time of year. Accompanying this strong short wave is a stout 80-100kt. 500mb. jet streak, overall cape values in the 1000-2500 j/kg. range, not to mention bulk shear values of 50 knots or so. All the ingredients coming together to manifest all modes of severe weather. The chief negative I see here is that severe parameters would be maximized just after sundown, so with loss of diurnal heating, this could have a mitigating effect on the severity of storms. Still, with all the dynamics associated with this strong short wave, explosive discrete cellular growth will be most likely in the CDS region on into SW Okla. If the NAM nest verifies, a 2-4 hour period of rapidly moving cells with strong vorticity tracks will move northeast into south central and perhaps central OK. by the mid evening hours before quickly congealing into a QLCS system where quick spin up TOR's won't at all be out of the question. I think the chief threat will be intense wind gusts due to downward momentum from the jet streak for cells to tap into. As the evening progresses, tornado threat may decrease but widespread SVR gusts will be common, along with hail up to 1.5", but I would not be surprised to hear of close to 3" hail in the most robust updrafts in SW. Okla. Unfortunately, from a chaser's perspective, the best of everything happening will be around dusk into the evening hours.. so chasing these storms could be a challenge, not to mention the mounting anxiety of the general public being this will largely be an evening/night time event. I'll be surprised if there is not at least 3 or 4 confirmed TOR's that will make haste in a northeasterly direction at 45kts or better. Maximum wind gusts of 80 knots are also possible. I will be chasing this, and my initial target will be the AXS area by around 23Z then adjust from there. Ground zero area for the most intense activity would be the Wichita Mountain area up to possibly the Fort Cobb Lake area. I'll be eagerly awaiting future runs of the NAM and HRRR runs as any deviation to the north could put the greater OKC area and my humble abode near Piedmont in the crosshairs. I hope there is some good feedback from those of you far more experienced in forecasting than I.
 
Feb 19, 2021
82
113
6
Wichita
Here is my tornado forecast (1030a Sat), using the risk categories that have been explained on my blog several times (including a one cat elevation for after dark occurrences if sig tors are expected). Unlike SPC in their 1730Z, I do not have the entire Metroplex in my "significant" area as I think the dynamics will be too far north and it will be after sunset.

Like Rocky, I'm concerned about clogged roads and I have mentioned it on my blog's discussion:
UPDATE on Tornado Risk in Southern Great Plains Sunday Afternoon and Night
To avoid the traffic issue, I am recommending that people get their families ready to pull the trigger on sheltering earlier than usual.

I'm not going to chase this tomorrow for three reasons:
  • Traffic congestion.
  • Time of day.
  • A possible better situation for Kansas on Tuesday. The new ECMWF has a cluster of strong thunderstorms developing @ 21Z Tuesday in far N OK ahead of the main action. As we know, supercells ahead of the main line can be tornado producers that are often easier to chase.
Good luck and be safe everyone!!


10-10 SVR.png
 

Jeff House

Supporter
Jun 1, 2008
618
684
11
Chattanooga, TN
www.linkedin.com
Thought about going out there for the two-out-of-three day sequence; however, Sunday has issues mentioned above. OKC and close to dark. If one adds a category for each of those, one gets High from the official Enhanced. Traffic even on a Sunday, chaser-con on a holiday weekend, going toward night and going toward OKC sounds like too much work.

Though not a travel set-up for me, the set-up is definitely worth a chase for residents and Storm Track members in the area. I believe the kinematics and directional shear will support sups before it congeals and goes upscale. Now looks like a couple good hours, vs insta-line. However it'll be close to dusk. Agree with SPC that QLCS tornadoes are possible later; however, that's not our interest. I think one or two sups will be capable of tornadoes right before dusk.

Some CAMs have morning to midday showers, which is desirable if they lift out of the chase area. Lay down some outflow, which would help targeting decisions and nowcasting. I like southwest OK in case any said boundaries keep sinking. Of course a failure of showers might allow farther north. I'd rather north of I-40. Either side of OKC for both the public and for chaser safety.

I'd target any outflow and the dry line. This late in the season I can't justify the cold front - even with a nice boundary intersection. Be a tough call if CF-OF but no DL-OF; in that case, maybe just go WF east of surface low. I will opine again on Sunday.
 

cdcollura

EF5
Jun 12, 2004
1,411
192
11
52
Sunrise, Florida
www.sky-chaser.com
I am looking at this and decided to head out on Tuesday's setup (Oct 12) in Kansas since I will also be in Denver (tentatively) this coming week. Like Jeff said this (Sunday, 10/10) is not an ideal setup warranting a long trip out there, so local folks it's a good chase opp. The only think I do not like are the fast storm motions, after dark kinematics-max, and the rapid evolution to a squall line.
 
Aug 9, 2012
485
1,047
21
Macomb, IL
stormoptics.smugmug.com
I will not be heading out for this event and electing to chase in Central Illinois on Monday as the system progresses east.I don't think I could do an 11 hour drive to SW Oklahoma and then make it back home to chase a potential tornado event on the home turf with my back and leg conditions.

With that said.... I'd probably target Altus, OK for supercell development around 6pm tomorrow evening. I think there is a short window for a decent tornado threat (possibly significant) in SW OK/NW TX from 6pm onward.

However as others have stated storm motions will likely be extremely fast (35-40+ knots) and with a cold front approaching from the WNW, storm mode will likely grow upscale rather fast (should be noted that there have been past events where the cold front has held back further than models suggested and led to a larger tornado event than forecast, not saying this will happen, but it is worthy of keeping in mind....although I always go with the saying that cold air usually wins out...so I'd expect a rather fast transition within a couple hours of initiation.

However QLCS tornadoes and intense wind gusts (70+ mph) will likely still occur and impact the OKC/Tulsa areas (7-10pm) northeast into the Ozarks overnight (12-4am). It's hard to say if this will be a continuation for the next day (Monday) in the MS river valley region or whether we see new development or not in a dry slot, models are struggling with this.

Regardless, if I lived within 5 or 6 hours of the area, I'd definitely be chasing, but 11-12 hours isn't doable with sunset coming early this time of year. Makes me sad to miss it, but I do think it is a respectable event given the amount of moisture in place, instability, and shear combination. I think there is a good shot at a respectable tornado. Whether it is visible from a chasing standpoint or not, is another story. I'm not exactly great at the art of divination if you know what I mean :). Good luck to those heading out! At least there is something interesting to watch other than grey skies and fog (weather here in IL lately).
 
Jun 4, 2018
107
100
11
Altus, OK
I live in Altus, OK and I'm currently planning to chase tomorrow. After my abysmal spring, a setup like this, on a holiday weekend, literally in my own back yard is simply too good to pass up. I'll likely target my couch until about mid afternoon, then head east along US-62 between Altus and Lawton. From there, the road network is quite good with plenty of opportunities to move north from there to stay with any storms that may form.

I will note though, if things start to trend worse for the Altus area, I'll likely change plans and stay with the family and monitor incase we need to take shelter. It wouldn't feel right leaving my wife and kids to fend for themselves like that. Regardless, I'm looking forward to see what the models have in store as we get closer.
 

Jeff House

Supporter
Jun 1, 2008
618
684
11
Chattanooga, TN
www.linkedin.com
Event is on track for all of central Oklahoma. On visible and radar one can note lift with increasing showers behind the CF. Lift is discernable on IR and vapor too.

One can see following surface obs with time and a visible loop, the boundary in western Oklahoma is holding steady after lifting a bit. Other perturbations are noted propagating east on visible, but those are not the boundary. SPC did right lifting the northern edge of the MDT.

While not a classic DL, a pre-frontal trough sits in western Oklahoma. I'd target that boundary intersection with the east-west boundary from my previous paragraph.

NAM and HRRR continue to depict a couple chasable hours. Should be 2-4 cyclical sups. Can we spread out for once?

Only time will tell. Fast motions and crowds will require extra cation and situational awareness. Good luck and be safe!