2024-10-30 EVENT: KS/OK

[Mike Smith]

Really surprised no one has started a thread on this one. I believe there is a significant chance of severe supercells and tornadoes over Kansas south of the Turnpike and over Oklahoma east of I-35/north of I-40. Td's in that area will be as high as the mid-60's.

The mesoscale models are pretty insistent CAPE will ≥ 1000j with good turning in the lower levels.

At 7pm CDT, the ECMWF shows eastern Kansas in the right rear of the jet at 250 mph with 90 knot winds.

The one negative is sunset at Ft. Scott, Kansas (to pick a location) is 6:25pm.

 

[Andrew Fryhover]

I'm planning to chase tomorrow. I think the most likely area will be up near Blackwell?

 

[Dan Robinson]

This setup is currently a no-go for me for a couple of reasons. The cold front may crash the party early in much of the Kansas risk area. Models show storms going up pretty close to the front as it is up there, even without considering how models often underdo the progression of these cold fronts. The Oklahoma dryline looks a little better in terms of storms staying ahead of the front longer, but the best area there looks to be in the forests east of I-35 and mostly after dark. My current plan is to just wait on the lightning to arrive here overnight, but will re-evaluate things in the morning.

 

[S Sherrod]

I’m with you Andrew. If things hold Blackwell is a good starting point. I may go to Ponca city so I can get south east a little easier. Waiting to see the updates around 12 today.
I want to see the dew points and how far south/southeast the triple point sets up

 

[Mike Smith]

Here is my forecast of the area with the greater tornado risk fro 5p to 8p this evening. For the last week of October surface CAPE of 1,700 to 2,000j along with the nice turning in the low levels should be plenty.

Good luck and safe chasing!!

 

[S Sherrod]

Thanks Mike. You’re the man! I hope that southern part can stay discreet. Decent dewpoint but need to get rid of this cloud layer. Be safe everyone !

 

[Andy Wehrle]

Seems front-parallel storm motion/undercutting combined with inability of any discrete cells to take root away from the front really did in the tornado threat today. I may have missed it since GR Level 3 stopped displaying warnings at some point during the afternoon, but I was also monitoring Radarscope on my phone and I don't think I saw a single tornado warning even issued in Oklahoma or Kansas; the only one I saw was for a bowing segment in Iowa.

 

[Mike Smith]

There was evidently a tornado in far NE Oklahoma which did damage. It might have crossed the border into Missouri.

That said, that was pretty much it yesterday.

Something in the current generation of models seems to lead to the over forecasting of tornadoes. I'm trying to figure out what it is.

 

[Brett Roberts]

JMHO, but I don't see yesterday as a clear example of NWP failure. Virtually all CAM output I looked at in the 48 hours leading up to the "event" showed extremely messy, largely linear convection right along the front sweeping across the area. UH, while sometimes decent in magnitude, mostly had a telltale messy character as well. It wouldn't have surprised me to see a few more QLCS tornadoes than we actually did, but it isn't at all surprising that there were no daytime tornadoes or tornadoes from classic supercells.

Aside from CAMs, the warm sector environment depicted by convection-parameterizing models ranged from very unimpressive to moderately impressive, with the more impressive end of that spectrum generally represented by models that underdid mixing and were too late in depicting widespread convection (e.g., yesterday morning's RAP runs).

If there's one area where "guidance" deserved blame, it would have to be post-processing techniques like Nadocast and SPC's calibrated HREF-based suite of severe probabilities. All these methods produced 10-15% tornado contours, and Nadocast included a hatched area. One weakness of these methods is that HREF UH is an important input to them (as it should be), but when large UH is produced by convection right along or even just behind a surging front or other boundary, the algorithms sometimes fail to "appreciate" fully that this UH is detached from the favorable warm sector environment just to its south and east. In other words, it's easy for us to look at a HRRR run and recognize manually that the big UH streaks in KS yesterday were from storms likely getting undercut, but some of these algorithms may give those UH streaks at least partial credit as tornado threats for being so close to favorable STP values say 10-30 miles to their east.

On a less NWP-specific note, having now chased based out of central OK for almost 20 years, it's humbling to realize how many of these characteristic "big trough and good traditional parameters, but messy and slightly veered out" busts or semi-busts we continue experiencing near and just W of the I-35 corridor in OK. I recall multiple events pretty similar to this, with similar forecasts, as an undergraduate in the mid-late 2000s. Fast forward to this year, and we've had several of these, including yesterday. I must admit, if you told me back then that there'd be relatively minimal improvement in the false alarm rate for this regime over the next 20 years (and even that cutting-edge AI/ML methods would highlight them as big events), it would've surprised me.

 

[William Monfredo]

...realize how many of these characteristic "big trough and good traditional parameters, but messy and slightly veered out" busts or semi-busts we continue experiencing near and just W of the I-35 corridor in OK.

I know; 10 p.m. OKC radar above. I did not want to rain on anyone else's goals yesterday, because chasing's what you make it. But, at some point one uses the analysis of the setup as well as gut hunches to decide how much time, money, energy to put into it.
So, I didn't chase yesterday. But think about this spring, when two EF-4s occurred at night on a couple different days, one near Marietta, OK and another near Barnsdall, OK. At some point, it's all about the nighttime, low-level jet seemingly. What if you're not into waiting for night chasing?

 

[Mike Smith]

William and Brett,

Thank you for the responses. We certainly are not making the progress in tornado forecasting and warning I would have expected 20 yr ago, either. I am getting a medical treatment at the moment and the man next to me was griping about yesterday's tornado watch and I don't blame him! We have had a number of bad busts in Kansas this year. We lose credibility every time one of these occurs.

I'm so old that I remember significant tornadoes occurring as early as 2-3p local daylight time (Attica, "Katherine Carpenter School", etc.) but we never seem to have those any more.

Something has changed. I wish I knew what it was.

 

[Ben Holcomb]

On a less NWP-specific note, having now chased based out of central OK for almost 20 years, it's humbling to realize how many of these characteristic "big trough and good traditional parameters, but messy and slightly veered out" busts or semi-busts we continue experiencing near and just W of the I-35 corridor in OK. I recall multiple events pretty similar to this, with similar forecasts, as an undergraduate in the mid-late 2000s

Yesterday seemed like a carbon copy of 2008-11-05. One of these days, a setup that looks like that is going to overperform and make us look like liars. Still waiting though...

If there's one area where "guidance" deserved blame, it would have to be post-processing techniques like Nadocast and SPC's calibrated HREF-based suite of severe probabilities. All these methods produced 10-15% tornado contours, and Nadocast included a hatched area.

This is a feature, not a bug. Let the feature stay there to remind some of these chasers they should still learn how to forecast

Didn't see anyone talking about the little (gus)Tornado thing up in Kingfisher County. Cute little thing.

https://twitter.com/x/status/1851767122088632384

 

[James Wilson]

Didn't see anyone talking about the little (gus)Tornado thing up in Kingfisher County. Cute little thing.

https://twitter.com/x/status/1851767122088632384

I was there and thought it was a gustnado at first but there was actually rotation above it so I counted the massive tornado LOL