5/12/10 DISC: KS/OK

[Mike Peregrine]

I wanted a place to talk about the weirdness that was yesterday ... maybe get a little closure.

I know we talk about high CAPE overcoming weakness in shear, but it really seems to me that every high instability day with mediocre wind ends up like yesterday in Kansas. You would think as the day/evening went on, things would only improve, but that was definitely not the case. It only got worse. What was the deciding factor? Leftover boundaries? Weak helicity? Moisture was no factor - I couldn't keep my windshield free of fog the entire time.

The storms seemed to be pulsing. I wasn't watching the mesonet to see what was going on over OK, but maybe someone who was can contribute what it was about the environment down there that stayed supportive.

 

[Rob H]

I took a quick look at things in that area yesterday to help a friend who was chasing with intermittent data. There was an area of higher helicity with Emporia at the bulls-eye, and the tornadic storm that moved into McPherson was on the left edge of that area.

I recall seeing a plot of CAPE vs. helicity for tornadic cells and the massive CAPE environments had a 0-2km(going off memory) helicity of at least 70-80. It didn't look like the area south of Wichita even had that.

edit: I was a little off on the numbers, but here is that plot: http://www.crh.noaa.gov/lmk/soo/docu/supercell.php

 

[Brian Stertz]

Problem was that I saw yesterday for bigger things was that the storms could not move off the boundary so either got updrafts rained on or undercut by outflows.
Was still a bunch of cap east of the boundaries so the storms were rooted above BL and then rocketed northeast and had hard time getting anything of interest and sustained spun up. I stayed home when I saw initiation so far west and that it was not too likely things were going to be catchable or worthy of catching I should say. A good day where parameters appeared to be huge but outcome was kind of generic for a May event. Congrats to those who bagged a 'nader or two yesterday.

 

[Rick Schmidt]

Did anyone get any images of the 3 tornado touchdowns in southern Ks. yesterday? I was about 45 minutes late getting there, and missed them.

 

[Michael O'Keeffe]

I think Brian nailed it on the head about storms being undercut by the boundary. I also got on the McPherson storm late SW of Herington and it was completely outflow dominant. I knew that storm needed to anchor onto the stationary front or it would eventually be undercut and it never did. So that storm along with all of the other cells along the cold front became undercut after only a few hours. However had it made a hard right turn to the east it would've been a different story likely.

 

[Mike Peregrine]

Well Brian ... I'm going to start giving you a call before I drive anywhere beyond Jct City on a day like yesterday. Could have saved me some gas. You're probably correct in the way you're looking at it too. I was in the exact same spot on the Dickinson/Morris Co. last week and watched while approaching from the north as it made a hard right turn in that same spot. Driving over there yesterday, I kept thinking the storms would do the same, which is what caused me to approach through Council Grove on 56 instead of from the north on 70. Since it didn't work for me last week, I thought it would this week, but nope. Guess that's what makes it a challenge.

 

[Jayson Prentice]

Numerous damage reports came in across the Kansas City metro last night as the line of thunderstorms began to bow out entering western portions of the metro. Damage reports of not only trees destroyed, but also several out buildings and even an anchored barn near DeSoto, KS. Some of the damage was fairly significant, including a trampoline being lifted and embedded into the side of a house as well as several 2x4's that were impacted into the side of a building. These damage reports also come in two distinctive lines across portions of Johnson county...

Viewing the KEAX radar imagery with approximate storm motion of 242 degrees & 57 kts shows two areas of rotation that lines of very well with these two damage paths. The rotation was fairly weak and broad at times, but the amount of damage in a few places definitely warrants a look as to whether or not they could have been at least brief spinups on multiple occasions (damage paths were 8 miles and 12 miles long respectively).

I have some images of the damage locations with velocity data overlay, will get those posted after my 3-day weekend... NWS EAX was out surveying some of the damage, so hopefully they will have a complete report as well to share.

In addition, a possible tornado occurred in Clinton county Missouri where a very nice couplet was shown on radar and damage reports of homes may coincide well with the track.

 

[Mike Peregrine]

Some pics of the storm damage in KC here. It seems like we get some sort of major bow event in this city every single year. Very very strong winds at my place as it moved through. Trees over on their sides. Actually the most exciting thing for me all day.

 

[Brian Stertz]

Slept like a baby last night...had I still been in Tulsa....it would have been a different story. Looked like the worst of it passed north of my old place at 61st/Memorial. For
KC it was a wet mess with some bigger than micro bursts.

Being on a more limited budget, I am going to be dissecting chase potential and ops closely the rest of 2010. I plan on starting up my chase ops page Mike. I'll send you the link.

 

[Mike Peregrine]

Being on a more limited budget, I am going to be dissecting chase potential and ops closely the rest of 2010. I plan on starting up my chase ops page Mike. I'll send you the link.

This would be amazing. Gas is on me for at least one chase if you're game!

I can't believe you slept through that. It was roaring like a hurricane.