06/05/08 DISC: TX/OK/KS/NE/IA/MO/SD

[Mark Blue]

I am curious as to what others think about how today unfolded. With several PDS Tornado Watches issued early and throughout the day today (with accompanying MDs), I thought the number of severe storms was somewhat underwhelming based on what I was expecting when the day began. Did this happen because there wasn't enough day time heating in the warm sector (insolation), or was it due to some other factor such as the low level winds howling out of the south at such astounding speeds that any cells which did develop never had the chance to become discreet? Were the low level winds not backed enough in proximity to the surface low and warm front? There are so many ideas swirling around my head right now and I am wondering what others are thinking with respect to the events of today.

Mark

 

[Dustin Wilcox]

IMO the anvil blow off from convection in KS killed the E NE threat, as soon as I seen that I knew it was trouble, instability decreased and SB CINH began to increase through the late afternoon hours (never good), though it was clear this was occurring even before SPC continued to pound the threat with PDS Watches and Strongly worded MD's, so perhaps this wasn't the culprit. Plus I don't think the super backed mid levels helped things. At least the High Risk area, esp. the core of it in E NE was just a case of a severely botched forecast, this is the second time in a short period that E NE has been under a red alert high risk with the weather the talk over every cup of coffee drank in the small towns, only for practically nothing to happen, doesn't bother me any, though I'm afraid it's gonna leave a lot of explaining for local media.....

 

[Mark Blue]

Your first observation was something I felt all the way to the core of my gut this morning when I was looking at the visible satellite loops (anvil blow off downstream of KS convection). My wife and I also chased central and eastern NE today and ended up empty handed. We saw the TIV (under the tutelage of Josh Wurman) in York today and talked to David Hoadley at dinner tonight in York (he sat across from us at Applebee's), so I think other experienced chasers came to this general region today and ended up with the same result.

 

[afischer]

After messing with a few tornado-warned cells around Ellsworth and McPherson, I "off and on" chased a semi-discrete tail-end-charlie sort of cell from Hutchinson all the way to north of Topeka. I basically stayed with/ahead of it as best I could until it started to strengthen and got the tornado-warning. I then moved in for a close look between Council Grove and Manhattan... this was maybe 20 minutes after it got the tor-warning, about 645-700pm. It looked cold and trashy. Interestingly, the 00Z Topeka sounding was well-timed/placed for this storm. The sounding shows 50kts at 1km agl and 300 0-1km SRH for a right mover (seems pretty close to the storm's motion)... both being better than were forecast by the 12Z NAM-WRF. CAPE was moderately strong, though low-level CAPE was a bit modest. All in all, based on the direct observation in the near-storm environment, I'm surprised this long-lived and more-discrete-than-most storm wasn't able to do a little more... though it did start producing tornadoes later on up toward Falls City/Tarkio after more convection from the south merged with it (squall line tornadoes?).

 

[Josh Murfield]

IMO the anvil blow off from convection in KS killed the E NE threat, as soon as I seen that I knew it was trouble, instability decreased and SB CINH began to increase through the late afternoon hours (never good), though it was clear this was occurring even before SPC continued to pound the threat with PDS Watches and Strongly worded MD's, so perhaps this wasn't the culprit. Plus I don't think the super backed mid levels helped things. At least the High Risk area, esp. the core of it in E NE was just a case of a severely botched forecast, this is the second time in a short period that E NE has been under a red alert high risk with the weather the talk over every cup of coffee drank in the small towns, only for practically nothing to happen, doesn't bother me any, though I'm afraid it's gonna leave a lot of explaining for local media.....

It worries me, too, about the botched red alert high risks here lately, because I already hear it from people at the office, they don't take this stuff seriously anymore. I had people telling me "High Risk, I've heard that so many times and we never got anything". When something finally does produce as expected around here these people won't even be paying attention.

It was interesting that even as evening arrived with it becoming painfully obvious nothing was going to happen here in NE SPC still had the high risk in place, and when the TOR watch for eastern Nebraska was renewed they kept the PDS wording in it, and this was not terribly long before large parts of the western end of that watch were being cancelled!

 

[Tim Stoecklein]

I'll be the one who swims upstream here instead of floating along with the current....

Taking a look at the soundings from 0z last evening clear through 0z this evening, it seemed obvious the potential was there. I sent out more than my fair share of e-mails to friends and family in northeast KS telling them to keep their eyes to the sky, no different than the SPC or local media outlets. Was it a 100% guarantee there would be enough verification for a High Risk? No way, never is really. If you look at the percentages placed by the SPC for severe events throughout the day, with the exception of the 30% area in NE, they didn't really add up to a traditional HIGH RISK. However, with storm motions forecasted, and in most case verified, to be in the 45-65mph range, I think the increased level of awareness was appropriate.

I guess I see a higher risk involved with high speed storm motions, tornadic cells embeddend in linear systems, and significant potential for widespread damage due to high winds as more of a risk to the public than a discrete supercell moving at 20mph. Maybe someone else saw it the same way today.

I think the SPC and local media I saw did a heck of a job today. Special props go out to Jeremy Goodwin and team with WIBW in Topeka. They were all over it with their streaming coverage of the eastern KS impact.

 

[Bill Schintler]

What happened today...?

1) The north target (NW IA/SW MN/NE NEB, along the WF) was toast today due to the extensive MCSs that affected NEB/IA/MN last night. There was no way for the airmass to recover in areas north of I-80 despite the strong synoptic dynamics.
2) A tongue of dry air between 900 and 700 mb caused the demise of the storms near York, NEB late in the afternoon. This weakened updrafts and raised LCL levels.
- bill

 

[Dick McGowan]

Keep in mind, the high risk was issued for WIND, not tornadoes, not hail...wind...60 percent hatched. 15 percent hatched (significant) tornadoes is typically associated with your moderate risks. SPC talked about the squall line most of the day in their MD's. They never once mentioned "violent" tornadoes, but rather "strong." This high risk will verify with the wind reports that will continue to come in. They issue these outlooks for the public, not for storm chasers. Straight line winds can still cause considerable damage to property and life.

 

[Mitchell Daszewski]

Keep in mind, the high risk was issued for WIND, not tornadoes, not hail...wind...60 percent hatched. 15 percent hatched (significant) tornadoes is typically associated with your moderate risks. SPC talked about the squall line most of the day in their MD's. They never once mentioned "violent" tornadoes, but rather "strong." This high risk will verify with the wind reports that will continue to come in. They issue these outlooks for the public, not for storm chasers. Straight line winds can still cause considerable damage to property and life.

Agreed. I don't know why there's this thought that High Risk = discreet chaseable long lived tornados. It's a high risk for severe storms, and it verified IMO.

 

[Dustin Wilcox]

Keep in mind, the high risk was issued for WIND, not tornadoes, not hail...wind...60 percent hatched. 15 percent hatched (significant) tornadoes is typically associated with your moderate risks. SPC talked about the squall line most of the day in their MD's. They never once mentioned "violent" tornadoes, but rather "strong." This high risk will verify with the wind reports that will continue to come in. They issue these outlooks for the public, not for storm chasers. Straight line winds can still cause considerable damage to property and life.

IDK, a 30% hatched area for tornadoes is pretty aggressive, and certainly suggests that they thought there was an elevated tornado threat, not to mention the probabilities on their PDS watches >95% of two or more tornadoes and I think it was 70% chance of F2-F5 tornadoes. Give them the benefit of the doubt and say the high risk was merely for the wind threat, still was clearly a hardcore botched forecast, the initial core of the High Risk saw absolutely nothing, hard pressed to find a rain drop let alone a svr report. It's the local media, news stations and radio stations who get the shaft on a day like this, they do their job and for the better part of a day they pound the fact that severe weather will ravage the area, and then when nothing happens they get to do all the explaining.

 

[Mark Blue]

Keep in mind, the high risk was issued for WIND, not tornadoes, not hail...wind...60 percent hatched. 15 percent hatched (significant) tornadoes is typically associated with your moderate risks. SPC talked about the squall line most of the day in their MD's. They never once mentioned "violent" tornadoes, but rather "strong." This high risk will verify with the wind reports that will continue to come in. They issue these outlooks for the public, not for storm chasers. Straight line winds can still cause considerable damage to property and life.

Dick,

I understand the function of the SPC in that they are there to protect the public from any and all severe weather threats up to and including straight line winds from squall lines, which are dangerous to life and limb. I am in no way throwing stones at the SPC because today was a bust for chasers - definitely not the tone I want this message to take. I am simply trying to take some "lessons learned" from today's chase and nothing else.

Thanks,
Mark

 

[Josh Murfield]

Agreed. I don't know why there's this thought that High Risk = discreet chaseable long lived tornados. It's a high risk for severe storms, and it verified IMO.

Actually at least here in eastern Nebraska, they hit the "strong long-track tornadoes" thing pretty hard, seems that was the main focus of the forecast discussions with large hail, strong winds, etc. being the secondary thoughts. But even at that, most of the region here didn't get a thing- no tornadoes, no wind, no hail, not even any rain.
I also don't want to sound like I'm bashing the SPC- they have a tough job and do it very well- today was just a head scratcher, at least locally here I've never seen a day hyped this much that doesn't really produce anything at all.

 

[Dick McGowan]

Dick,

I understand the function of the SPC in that they are there to protect the public from any and all severe weather threats up to and including straight line winds from squall lines, which are dangerous to life and limb. I am in no way throwing stones at the SPC because today was a bust for chasers - definitely not the tone I want this message to take. I am simply trying to take some "lessons learned" from today's chase and nothing else.

Thanks,
Mark

I wasn't directing it at any certain person, I've just watched some broadcast stations that were calling today, "The biggest outbreak since 1974," so I'm sure they'll be the ones questioning the high risk and what not, since another town wasn't wiped off the map. And I'm sure some who didn't see a tornado on this high risk day, will certainly look for someone/something to blame.

With storm motions as fast as they were, we had to play very "conservatively" today, and had to plan each scenario out with, "If this happens...or if we get caught in the path, this is our escape route..." Things can go from fine, to "Oh s***, how did we end up in this situation" in a matter of seconds. Not a chaser-friendly event that's for sure.

FWIW, IMO per SPC's mesoanalysis, the 500's seemed to be more backed and unidirectional with the 850 and surface winds, and it looked like a cold pool formed rather quickly in the late afternoon in Kansas. The instability and speed shear were there, the directional shear wasn't.

 

[Brett Roberts]

For the southern target, I'm curious as to any professional or expert opinions on exactly where things went wrong. As a novice, two primary explanations came to mind on the rather depressing drive home this afternoon: 1) mid-level flow roughly parallel to the NNE-SSW oriented dryline throughout KS and OK, and 2) extremely high T/Td spreads for the airmass in which convection initiated (from far W OK into central KS). I'm not sure either of these factors were incorrectly forecast, though, as I recall models showing temperatures warming into the 90s throughout most of the moist sector near the dryline, as well as the parallel-flow issue; this is why I'm wondering if there were additional factors at work. The initial storms in SW KS and NW OK early this afternoon took on a strung-out appearance on reflectivity, but the same can be said of several other days I've chased that ended up significant tornado outbreaks (5 May 07, 22 May 08, 23 May 08). Those days also featured very meridional mid-level flow, but perhaps not having 35-degree dewpoint depressions helped in limiting cold pool formation.

 

[Jesse Risley]

We certainly didn't go away without a great chase today. Putting that aside, I don't fault the SPC for today. They did the best job possible given the forecast models and the potential that did exist for a more widespread severe weather event today.

It's often hard to predict seemingly miniscule problems that can really blow a forecast (i.e. cloud cover that limits instability). The SPCs job is to provide forecasts for the general public based on given parameters, and the ingredients were in place for at least a widespread damaging wind event, which appears to be somewhat verifying.