May 15th - 20th Plains Storm/Severe disco

[David Reimer]

Our video of the mile-wide wedge approaching Cleburne last evening. 

[AtticaFanatica]

The evolution of the Arlington cell looked really familiar last night. On June 1st, 2011 there was a funnel cloud sighted in my home town with a similar "dangling" pendant style hook.  As the cyclonic circulation tightened at the base of the inflow, rather than seeing the echoes continuing to spiral inward as often witnessed in strong tornadoes, instead there is a doubling back, forming an "S" shaped signature with signs of weak anti-cyclonic rotation just in front.   I'd be interested to hear some thoughts on the mechanics of this if folks have an idea what's going on. 

 

 

 

Hey, it's great to be talking severe weather with you again! Looking forward to late May-July, as always (let's see if we can get another EML up this way haha).

It is my understanding that there are occasionally 2 RFDs in the process of tornadogenesis with the second usually adding the strongest source of M. These processes were highlighted nicely in the Vortex II / Markowski papers that we discussed last year. Is this what you are referring to or did I miss what you were saying?

 

 

Been proposed that the "S" signature is the RFD coming around the south side of the tornado. It matches up with the idea that the RFD can help give the storm it's final spin to drop the tornado. And what HM said - that was added as I'm typing.

 

Meanwhile the 12Z NAM is in. Fires convection Saturday along an apparent boundary intersecting the DL in KS/OK. That boundary is probably outflow OFB left over from Fri. Suppose it would be there long as LLJ stays decoupled. Mixing down would destroy the OFB. Concerns of a high bases noted that far south where it'll be hot! Otherwise we got the synoptic WF farther north.

 

Sunday looks good with one or more OFBs around plus the WF. Like those days. Multiple targets spreads out chasers. The one DL one WF is where you get 2,000 people on the triple point. Booo! Monday still showing that southern jet max coming out on the south end of everything. I have not looked hard at the synoptic WF and low up north, but not too shabby. Cheers!

 

 

Thanks guys.  Both times I've seen this it turned out to be a null case (although a rope funnel might not be considered null), and so I was curious if it may have a destructive influence on tornadogenesis.   Fully admit though that 2 cases is not significant.   I'll reread the Markowski paper.

 

Anticylonic hooks or flares are seen occasionally. A good example is discussed in Fujita (1981): http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281981%29038%3C1511%3ATADITC%3E2.0.CO%3B2

 

It's also been seen in mobile data, for example here: http://journals.ametsoc.org/doi/pdf/10.1175/MWR3349.1

 

I don't know that they have any particular predictive or diagnostic value in tornadogenesis. 

[Buckeye05]

Seeing pictures of clean slabs in Granbury (on my phone can't post). Anchor bolts look too widely spaced for EF5, but I honestly wouldn't rule it out.

[soonertrey]

Looking at the 12z NAM I'm a little concerned of the T-Td spread in Central OK on Sunday afternoon/evening.

[mappy]

Seeing pictures of clean slabs in Granbury (on my phone can't post). Anchor bolts look too widely spaced for EF5, but I honestly wouldn't rule it out.

 

There is a post that tornadotony wrote for ustornadoes.com that explains how pictures of tornado damage do not tell the whole story when it comes to ratings; perhaps you should read it

[Chinook]

I see the tornado report located at 6 SE Granbury on the SPC storm reports page. Is this the same or different from the Cleburne tornado? 

[Buckeye05]

^I have, but these pictures are pretty close-up and clear. I do know what to look for when it comes to the relationship between the EF scale and house anchoring (or there lack of)...

[David Reimer]

I see the tornado report located at 6 SE Granbury on the SPC storm reports page. Is this the same or different from the Cleburne tornado? 

 

They were produced by the same supercell, but I believe they are going to end up being separate tornadoes. There looked to be a occlusion in there between the two events. 

[mappy]

I see the tornado report located at 6 SE Granbury on the SPC storm reports page. Is this the same or different from the Cleburne tornado? 

 

I'm surprised there are only three SPC tornado reports, when DFW WFO has a prelim count of 10

[radarman]

Anticylonic hooks or flares are seen occasionally. A good example is discussed in Fujita (1981): http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281981%29038%3C1511%3ATADITC%3E2.0.CO%3B2

 

It's also been seen in mobile data, for example here: http://journals.ametsoc.org/doi/pdf/10.1175/MWR3349.1

 

I don't know that they have any particular predictive or diagnostic value in tornadogenesis. 

 

Good stuff.  There are certainly similarities to the structure of the Grand Island tornado, just much weaker on the whole.   We had a good look at the anticyclonic Bray tornado on May 10th 2010, but that was not a satellite to a primary rotation as these seem to be.

[OKpowdah]

12z GFS ... pretty decent convergence along the dryline Sunday evening. With CAPE up to 4000 / LI -10 to -14 just to the east over central OK.

 

[HM]

Anticylonic hooks or flares are seen occasionally. A good example is discussed in Fujita (1981): http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469(1981)038<1511%3ATADITC>2.0.CO%3B2

 

It's also been seen in mobile data, for example here: http://journals.ametsoc.org/doi/pdf/10.1175/MWR3349.1

 

I don't know that they have any particular predictive or diagnostic value in tornadogenesis.

Thanks. Always nice to see you post.

 

Good stuff.  There are certainly similarities to the structure of the Grand Island tornado, just much weaker on the whole.   We had a good look at the anticyclonic Bray tornado on May 10th 2010, but that was not a satellite to a primary rotation as these seem to be.

I'm sorry man; I didn't see the anticyclonic hook on the radar you linked. Do you have a link to a more detailed radar of it? If not, don't worry about it.

[SluggerWx]

From Dallas Morning News...

Before:

 

: 

 

After:

[Chinook]

12z GFS ... pretty decent convergence along the dryline Sunday evening. With CAPE up to 4000 / LI -10 to -14 just to the east over central OK.

 

 

Compare this to Saturday. In the capped sector, around Springfield MO, the GFS is predicting 6000 J/kg of CAPE. Haven't seen 6000 for a while! 

[SluggerWx]

This damage really reminds me of the Ringgold, GA EF-4 on 4/27/11 - except for when I compare the worst areas of the two storms.

 

I have a strong feeling this will be upgraded to EF-5 damage - you just don't see devastation like these two pictures except for with EF-5 (balls of debris with rolled up/twisted cars embedded in the debris piles)

[KSWx]

From Dallas Morning News...

Before:

 

: 

 

After:

 

 

Heartbreaking... Here's to hoping any tornadoes this weekend end up in wide open fields.

[Buckeye05]

This damage really reminds me of the Ringgold, GA EF-4 on 4/27/11 - except for when I compare the worst areas of the two storms.

I have a strong feeling this will be upgraded to EF-5 damage - you just don't see devastation like these two pictures except for with EF-5 (balls of debris with rolled up/twisted cars embedded in the debris piles)

I wouldnt rule it out but I highly doubt it. I have yet to see a specific instance of damage that actually indicates solid EF5. It doesn't take an EF5 to mangle cars or sweep away wood frame homes with minimal anchoring. It lacks the classic hallmarks (well anchored homes gone, ground and pavement scouring, vehicles stripped to the frame, pronounced shredding of low lying vegetation ect.)

In any case, it was a surprising and devastating event. My thoughts and prayers go out to the residents of Hood County.

[KSWx]

I'm wondering if all of the fatalities reported were from those manufactured homes, there look to be quite a few in that pic above.

[thewxmann]

This damage really reminds me of the Ringgold, GA EF-4 on 4/27/11 - except for when I compare the worst areas of the two storms.

 

I have a strong feeling this will be upgraded to EF-5 damage - you just don't see devastation like these two pictures except for with EF-5 (balls of debris with rolled up/twisted cars embedded in the debris piles)

 

Eh, EF5's are hard to come by these days. Haven't really seen ground scouring or vehicles-wrapped-around-trees esque damage characteristic of one. As we have seen so often clean slabs don't tell us much except it's EF3+.

 

This may be one of those cases where windspeeds were strong but not truly violent, and most of the damage is due to the tornado just sitting in one area for a long time. The areal extent of violent-level damage seems to be relatively contained, but the fatality rate in those areas were probably rather high.

[SluggerWx]

I wouldnt rule it out but I highly doubt it. I have yet to see a specific instance of damage that actually indicates solid EF5. It doesn't take an EF5 to mangle cars or sweep away wood frame homes with minimal anchoring. It lacks the classic hallmarks (well anchored homes gone, ground and pavement scouring, vehicles stripped to the frame, pronounced shredding of low lying vegetation ect.)

In any case, it was a surprising and devastating event. My thoughts and prayers go out to the residents of Hood County.

Agreed - no difference to here whether it's EF-4/EF-5, though it does seem like the increased media around an EF-5 storm warrants more donations and helps with the rebuilding effort.

[HM]

The GFS is still a little bit slower than the 12z UKMET/GGEM and nestled nicely within the ensemble spread (not large). I'm still waiting on the complete ECMWF but it may be like the GGEM and not quite as fast as the UKMET / 00z EC. But I'm not sure on that.

Either way, it appears the modeling continues to advertise the potential for significant severe and possibly a tornado outbreak.

[KSWx]

The GFS is still a little bit slower than the 12z UKMET/GGEM and nestled nicely within the ensemble spread (not large). I'm still waiting on the complete ECMWF but it may be like the GGEM and not quite as fast as the UKMET / 00z EC. But I'm not sure on that.

Either way, it appears the modeling continues to advertise the potential for significant severe and possibly a tornado outbreak.

 

Where do you think the most potential is for Sunday?

[Buckeye05]

Cleburne tornado has been rated EF3

[OUGrad05]

Where do you think the most potential is for Sunday?

 

I know you weren't asking me but I'll chime in...it's still a bit early for me to start getting excited but I'm starting to buy into this setup....

 

If I go out Sunday, I'll target from Chickasaw up to may be Enid the way it looks right now.  Obviously that could change being several days out but really central OK is looking like the playground....including the OKC Metro.  Far northern target up around the low may also be decent.

[soonertrey]

 

I know you weren't asking me but I'll chime in...it's still a bit early for me to start getting excited but I'm starting to buy into this setup....

 

If I go out Sunday, I'll target from Chickasaw up to may be Enid the way it looks right now.  Obviously that could change being several days out but really central OK is looking like the playground....including the OKC Metro.  Far northern target up around the low may also be decent.

Yeah, a lot can change and probably will, but looking at some of the latest forecast soundings central/north-central OK looks pretty intense. 

[HM]

Where do you think the most potential is for Sunday?

 

Now that I've seen the new 12z ECMWF, it is clustered within the consensus speed (at least the operational), so we must account for the GFS being a little bit slow. This could affect how Saturday plays out, which ultimately affects where differentials/gradients may reside from overnight/morning convection.

I think your area is sitting pretty at the moment, along with SW IA / W MO / SE NE. The slightly quicker timing will also help with your hodos up that way on Sunday. The GFS's slower timing would slightly tamper with them, delaying improvement past peak heating. The faster speed and slight veered low-level winds could make the OKC area not the best location. I'm also not comfortable forecasting last-minute improvement in low-level fields as the next wave moves in from the West and pressures lower. In other words, how will convection down this way manifest/behave as these conditions change?

 

I'm just trying to answer "best" ...clearly all areas have tornadic potential.

[HM]

I know you weren't asking me but I'll chime in...it's still a bit early for me to start getting excited but I'm starting to buy into this setup....

 

If I go out Sunday, I'll target from Chickasaw up to may be Enid the way it looks right now.  Obviously that could change being several days out but really central OK is looking like the playground....including the OKC Metro.  Far northern target up around the low may also be decent.

 

 

 

Yeah, a lot can change and probably will, but looking at some of the latest forecast soundings central/north-central OK looks pretty intense. 

 

This is true if we take the timing of the GFS as most probable outcome. I think the issue in timing comes from an offshore vorticity maximum a couple hundred miles off the N CA coast. The GFS for several runs has had a stronger max here which may slightly but collectively/gradually slow down the southern end of the trough. It is currently all alone with its solution. We'll find out tonight and definitely tomorrow morning.

 

The slightly faster scenarios are still very threatening in OK but the best potential may be SE NE/E KS into SW IA/NW MO.

[KSWx]

 

Now that I've seen the new 12z ECMWF, it is clustered within the consensus speed (at least the operational), so we must account for the GFS being a little bit slow. This could affect how Saturday plays out, which ultimately affects where differentials/gradients may reside from overnight/morning convection.

I think your area is sitting pretty at the moment, along with SW IA / W MO / SE NE. The slightly quicker timing will also help with your hodos up that way on Sunday. The GFS's slower timing would slightly tamper with them, delaying improvement past peak heating. The faster speed and slight veered low-level winds could make the OKC area not the best location. I'm also not comfortable forecasting last-minute improvement in low-level fields as the next wave moves in from the West and pressures lower. In other words, how will convection down this way manifest/behave as these conditions change?

 

I'm just trying to answer "best" ...clearly all areas have tornadic potential.

 

 

I know you weren't asking me but I'll chime in...it's still a bit early for me to start getting excited but I'm starting to buy into this setup....

 

If I go out Sunday, I'll target from Chickasaw up to may be Enid the way it looks right now.  Obviously that could change being several days out but really central OK is looking like the playground....including the OKC Metro.  Far northern target up around the low may also be decent.

 

 

You guys are awesome, thanks. Another question if you don't mind -  how accurate do the Supercell Composites tend to be on the GFS? Haven't ever really seen them mentioned when I see you guys talking about the models.

[mappy]

VERY preliminary map showing tornado locations

 

https://maps.google.com/maps/ms?msid=209388568448965693700.0004bde22042464749bb8&msa=0&hl=en&ie=UTF8&t=h&ll=32.787275,-96.855469&spn=3.232371,8.239746&z=7&source=embed

 

 

more info will be added to it later

[CUmet]

To echo what some others have indicated, Sunday has pretty substantial potential.  While I don't expect anything of the magnitude of 5/24/11 or 4/14/12, things do look promising for a decent outbreak.  If I had to outline the highest tornado risk areas right now, it'd probably be east-central KS and perhaps northern OK.  I don't like areas farther north due to the backed and weaker upper level flow, and further south due to stronger capping and more isolated storm coverage.  Basically about from Salina/Topeka south to Enid-Ponca City, although obviously this is subject to change in the coming days.