Warren Faidley
Supporter
I would not be surprised to see a high risk issued for the derecho winds with the 2000Z update. Going to be a rare day where almost every severe hazard will be on the "extreme" level.
2023-02-26 EVENT: KS, OK, TX
- Thread starter Mike Smith
- Start date
Mike Smith
EF5
While I don't think this is an extreme hail day, I just sent a note to SPC inquiring why "EF-2 intensity" winds* (110-135 mph) doesn't equal "high risk"? I'm not sure why it isn't already high risk. I'm glad they expanded the tornado risk, but I think it needs to be further expanded north toward END.
Because this is an EVENT thread, I won't go into my concerns about SPC's risk categories and related issues. Regardless, this should clearly be a high risk day.
*Their forecast in the 1630Z outlook.
Mike Smith
EF5
Pertinent Non-Model Forecasting Technique
Back when dinosaurs roamed the earth (
), Col. Bob Miller -- in addition to his groundbreaking tornado work -- found that squall lines with a high risk of damage winds were preceded and then accompanied by a (his term) "fall/rise" couplet.
We have one of the most powerful fall/rise couplets I have ever seen today, especially since this is for two hours rather than the more standard three. This pretty much guarantees (in my mind) a powerful derecho.
Above, you'll see my posts about the extreme pressure falls in Kansas. They and this = non-model forecasting technique.
This is the type of thing I am considering putting in a book if there is enough interest.
Back when dinosaurs roamed the earth (
), Col. Bob Miller -- in addition to his groundbreaking tornado work -- found that squall lines with a high risk of damage winds were preceded and then accompanied by a (his term) "fall/rise" couplet. We have one of the most powerful fall/rise couplets I have ever seen today, especially since this is for two hours rather than the more standard three. This pretty much guarantees (in my mind) a powerful derecho.
Above, you'll see my posts about the extreme pressure falls in Kansas. They and this = non-model forecasting technique.
This is the type of thing I am considering putting in a book if there is enough interest.
Attachments
Jeff House
Supporter
I love me some ground truth methodology!
I also believe the tail end could get true supercells as it interacts with a boundary lifting north from CDS. It's a differential heating boundary. Should intersect nicely with the DL / prefrontal trough.
Trouble is that it'll probably be just after dark. Chasers should also mind storm motion.
I also believe the tail end could get true supercells as it interacts with a boundary lifting north from CDS. It's a differential heating boundary. Should intersect nicely with the DL / prefrontal trough.
Trouble is that it'll probably be just after dark. Chasers should also mind storm motion.
Ethan Schisler
EF5
Banking more on the southern stuff ongoing right now to take off versus the stuff in the Northern Panhandle. If one looks at mesoanalysis at 23z (5pm CST), there is an area of stable air over NW/W Oklahoma with temperatures in the low 60s along with a decent amount of CIN and drop off of CAPE. I wonder how this will impact any storms moving into the environment.
As pointed out above, any storm that could manage to ride along the southern part of this gradient could benefit from the thermal gradient and enhanced SRH it provides....not as if we need any more today lol.
Edit: I notice at 5:16pm they added a tornado warning for the storm I mentioned. I will say the gradient is oriented from NW to SE and storms are flying to the NE at 60+ mph, so it will be interesting to see if we get any long trackers out of this or it is just a brief ordeal with tornadogenesis as they cross the boundary....or perhaps the boundary lifts with them?
As pointed out above, any storm that could manage to ride along the southern part of this gradient could benefit from the thermal gradient and enhanced SRH it provides....not as if we need any more today lol.
Edit: I notice at 5:16pm they added a tornado warning for the storm I mentioned. I will say the gradient is oriented from NW to SE and storms are flying to the NE at 60+ mph, so it will be interesting to see if we get any long trackers out of this or it is just a brief ordeal with tornadogenesis as they cross the boundary....or perhaps the boundary lifts with them?
Mike Smith
EF5
03Z sounding from OUN before the tornado struck SE part of town. Note the helicity. The fact there was an inversion doesn't matter much when dynamics are this strong. Good thing the inversion was there. 
Warren Faidley
Supporter
Saw that this morning and my jaw dropped. I might frame it and put it on the wall. A -333 CIN totally destroyed by a 1000+ 0-1km SRH. I'm assuming there was also a lot of localized help by outflow / inflow interactions and other, yet-to be determined factors. Cannot wait to see a professional write up of this event.
Jeff House
Supporter
Wow looks like Oklahoma went with the Deep South overnight playbook. I read somewhere a modest inversion can actually strengthen overnight inflow. Believe its connected with LLJ mechanics. However that's more like a moderate inversion. The Plains gonna Plains!
gdlewen
EF3
I just checked the RAP 03Z vertical velocity model output. Look at the vertical velocities over Norman at 04Z--so I need to increase the max scale used in the contour plot.
Ethan Schisler
EF5
I've heard several people trying to call what happened on Sunday a "bust". I fail to see the reasoning behind this except from maybe a chasing standpoint?. However most setups with these types of parameters end up being messy anyway with a lot of storms, so I don't know after all these years what people expect? lol. IMO the best "chase" days are the 2% and 5% days that yield that most photogenic results at least from my personal experience. Alas I diverge....
There were A) numerous tornadoes confirmed B) some of which were strong (See Norman/Cheyenne OK/Shawnee for EF2s) and C) widespread destructive winds across most of the original MDT risk area including a 114 mph wind gust near Memphis, Texas. This follows along with the discussion mentioning wind gusts of 80-110 mph along with a few strong tornadoes.
Pretty high end wind event for late February for that particular area. I wouldn't be shocked if additional tornadoes are not confirmed via high resolution satellite in the coming days/weeks....
Mike Smith
EF5
Ethan,
I have some comments here, if they are helpful: How Did Yesterday's Tornado and Damaging Wind Forecast Work Out?
I have attached the SPC tornado forecast that corresponds to the time of the categorical risk. The red dots are tornado reports. There were also likely tornadoes near Tonkawa and near Augusta, KS that are not on the verification.
I have some comments here, if they are helpful: How Did Yesterday's Tornado and Damaging Wind Forecast Work Out?
I have attached the SPC tornado forecast that corresponds to the time of the categorical risk. The red dots are tornado reports. There were also likely tornadoes near Tonkawa and near Augusta, KS that are not on the verification.
