Author Topic: May 25 - 29, 2007 - Tornado Alley  (Read 16861 times)

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Offline Macca

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May 25 - 29, 2007 - Tornado Alley
« on: 27 May 2007, 01:26:27 AM »
Hi all,

Currently in Goodland, KS watching towering Cu go up and down like popcorn in a microwave. Given a little more heating and some more lower level convergence, these should develop into storms in the next hour or so. Low level shear isn't too bad with 850mb winds of 20-25knts from the south/south east and the mid levels are around 30-35knts from the W so an isolated severe storm isn't out of the question. Instability is a little on the light side thanks to relatively cool surface temps (mid 70's) and relatively low DP's (mid 50's) but CAPE is still around 1500-2000j/kg and the LI's are around -4 to -5 currently.

Once again, we'll play the watching and waiting game to see what develops over the next hour.

The next two or three days look like some slight risk potential for supercells and with more upper level support progged for Monday & Tuesday, we could seethe chance of a tornado or two as well.

Macca & Chris

Offline Macca

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Re: May 25 - 29, 2007 - Tornado Alley
« Reply #1 on: 27 May 2007, 10:10:55 AM »
Hi all,

WHOA!  WHOA AGAIN!  What a day!!!  We had the opportunity to go into Greensburg today but turned it down in favour of a chase.  It was looking pretty marginal with CAPE of 1000-1500j/kg forecast but a S’ly LLJ of 20-30knts and a weak mid-level impulse dipping down from the main upper trough to the N was producing 30-35knt westerlies at 500mb.  Upper level temperatures were also quite nice with -15C at 500mb.  What was interesting was the moisture levels we spotted in southern Kansas and also into the Oklahoma panhandle which saw DP’s in the mid 50’s.  Given that this moisture was to advect northwards during the day, we figured the area of NW Kansas was looking quite nice.  SPC had a slight risk area extending just down to Goodland with a 15% chance of hail and wind threats. 

Per the earlier post, we were in Goodland, KS with TCu going up to our S, SW and NW.  The stuff to the NW was bigger at the time but the stuff to the SW had more volume so we dropped about 8mi S of Goodland and didn’t move for over an hour as a nice little LP storm developed just to our SW and moved slowly NE.  We got some small hail (1-1.5cm) from it as it started to take on some nice structure with a solid base area and it was rumbling away nicely up in the anvil.  It intensified rapidly when it was just to our S and the precip area thickened up a bit.  It put down a little RFD which cut into the base and a small wall cloud developed and showed evidence of weak rotation for about 15 minutes or more.  The cell became more of a precipitator and took an east turn at this point and we watched from the west as long as we could until the base started to become obscured (road options were limited).  Shortly after this, SPC put out a Severe Thunderstorm Watch box for the area we were in, extending just south of Goodland to where this storm was.

Looking at radar and visually, you could see it was moving ESE now so we headed back up to I-70 and east to Levant, KS where we then dropped S to about 7mi N of Winona where we set up for another 35-40mins or so.  The storm had hardly moved (it was doing about 10mph) but was edging slowly SE towards us!  This is when things became really nice.  As we were dropping S from Levant, we could see a nice inflow band coming in from the S into the base (which was off to our west) but it wasn’t until we stopped that we could see the motion in this inflow band – it was RACING northward into the storm.  I’d estimate around 30knts – no less!  The storm rapidly became HP and developed striations and showed clear evidence of rotation (later confirmed by SPC who indicated it was a supercell in their warnings) and was now moving SE!  The mid level curved banding was incredible and the lighting (not lightning) was also just awesome!  Then…just in case this wasn’t enough...IT DEVELOPED A BEAVER TAIL which aligned itself ESE/WNW into the bottom of the striated base!  Can you believe this?  We still can’t!!  Under the beaver tail was orange from the setting sun, the core of the storm was green, there was blue sky out to the SW and then the inflow band, updrafts and striations in various shades of grey!!  The structure on this storm rivals that of May 22nd in Kansas in my opinion!  Just unbelievable!   
Eventually the storm encroached out location but we were able to move about 4mi S and we were in the clear again to watch as the storm put out a last ditch effort to produce something.  It wrapped up (for about the 3rd or 4th time) and had some nice rotation but there just wasn’t enough there today to get the job done (although we aren’t complaining after the awesome structure).  Several times during its life, the cell had genuine (weak) shear indicators on the Mobile ThreatNet and there were several times where it showed estimated hail sizes of up to 3 inches and cores of up to 70dbz!  We’ll have to check any reported hail sized but I’d expect at least golf balls to have been reported from this given the shear profile, moisture profile and also the upper level temperatures. 

Pictures here…

http://macca.bsch.au.com/gallery/20070525

On a side note, it took us over 2.5 hours of watching this storm to see any other chasers and I think in total we saw 6 or 7 other chase vehicles.  You’ve gotta love these high plains surprises!  Everyone was sensible apart from one person (who is lucky I cannot remember his name) who proceeded to follow chasers around and then TWICE parked his car right across the south bound lane of a relatively narrow country (sealed) road.  It did not matter that there was very little traffic using the road, it was just plain stupid. There has been quite a bit of negative publicity for chasers over here lately with the number of chasers on the road and their inability to obey road laws and also common courtesy to other road users.  This was a PRIME example of why chasers are getting this publicity and I do not believe this guy was a chaser as such.  Keep this in mind if/when you are chasing anywhere in the world…there are ALWAYS places to pull off the road completely. 

Thanks must go out to Jimmy for suggesting that this region could be worth watching today and also to our support bands being Foo Fighters, Offspring, Rage Against the Machine, Jane’s Addiction, Wolfmother, and Guns ‘n’ Roses. :)

Macca & Chris…totally stoked! 

Offline nzstorm

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Re: May 25 - 29, 2007 - Tornado Alley
« Reply #2 on: 27 May 2007, 07:38:07 PM »

Yes, the NZ team targeted the Colby area today and had an easy chase with the magnificiently structured HP storm developing nearby.
NW Kansas and Colorado seem to have a habit of rewarding the chasers who are loyal to this region. Second best storm chase day we have had since arriving in the US on the 12th.  Some of the NZ team head home today.

Steven Williams
Storm Chaser

Offline Jimmy Deguara

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Re: May 25 - 29, 2007 - Tornado Alley
« Reply #3 on: 28 May 2007, 02:40:33 AM »
Hi guys,

Fancy suggesting the region and not chasing it - had to drop off guys at OKC. I was hoping Macca and Chris were in that area! Rewards which makes me ALMOST as happy as being there. Macca and Chris are rubbing it in:)

We were able to do a little survey of Greensburg tornado damage - 306 photos later - it was time to go. I felt I had to return given this was a storm we chased and the way we felt on the night. I knew what the town looked like - now it is obliterated like a bomb had gone off. Just the massive scale of desctruction and the fact 3 weeks has gone by - we did not expect that much of the damage still remained. I know this is a case from media talk, but it will take years to recover. Thanks to Macca for talking to one of the locals - basically allowing for us to do this survey.

Photographs included below:

Visit one of the farmers who lost their house and barns.

car severely damaged


piece of wood speared through headrest


dead fish on the ground


Greensburg damage

Note the "F" likely stands for fatality and we noted 3 fatality sites in 4 consecutive houses


For all pictures:

http://www.australiasevereweather.com/photography/photos/2007/jd20070524.html

http://www.australiasevereweather.com/photography/photos/2007/jd20070525.html

Regards,

Jimmy Deguara
« Last Edit: 28 May 2007, 04:40:23 AM by Jimmy Deguara »
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Offline Jimmy Deguara

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Re: May 25 - 29, 2007 - Tornado Alley
« Reply #4 on: 28 May 2007, 06:24:15 PM »
Hi,

It is tragic that Michael Thompson has had to cut short his trip - particularly when you have been planned to do this for so many years - awaiting a strong Aussie dollar year.

But yes, certainly he should look back especially in regards to his tornado near Hill City - the structure and tornado one can rarely beat. That in itself makes this trip worth it for anyone.

Macca's pictures from the east has a beaver tail and contrast that resembles the June 2nd 2005 event:

 

Regards,

Jimmy Deguara
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Offline Macca

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Re: May 25 - 29, 2007 - Tornado Alley
« Reply #5 on: 28 May 2007, 10:48:08 PM »
Hi all,

Currently in Wray, Colorado (about 55mi N of where we started).  Storms have just developed on the intersection of the frontal boundary and the lee trough (as expected) about 10mi to our SW.  Meso analysis shows CAPE's already hitting 3000j/kg and LI's of -6 to -7 in the area where the storms are.  DP's are pushing into the low 60's atm (17C).  We'll probably only have a few hours to play with storms today before it gets a little cluttered.

Macca & Chris & Jimmy & Brad

Offline nmoir

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Re: May 25 - 29, 2007 - Tornado Alley
« Reply #6 on: 29 May 2007, 06:02:40 AM »
Storm east of Limon seems to be building south west towards a squall line  heading east. Loved the beaver tail storm guys , awesome.
Nick Moir
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and www.oculi.com.au

Offline Jimmy Deguara

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Re: May 25 - 29, 2007 - Tornado Alley
« Reply #7 on: 01 June 2007, 08:01:02 AM »
There was a reasonable confidence that the 29th May could yield something special in Colorado - structured supercells and even tornadoes. A tornado watchbox was issued and later issued further south. Unfortunately, the storms once developed, although tornado warned eventually became outflow dominant.

Here are some images from this day beginning near Limon and eventually down near Lamar:

 


We had fun with strong winds, hailstones, swirling dust and also tumbleweeds! The last picture represents a storm further south that initially took on a severe structure and hinting rapid intensification - though the cold northerly outflow simply undercut any chance of that.

Regards,

Jimmy Deguara
« Last Edit: 01 June 2007, 08:17:33 AM by Jimmy Deguara »
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Fryz

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Re: May 25 - 29, 2007 - Tornado Alley
« Reply #8 on: 10 June 2007, 06:53:37 PM »
Hello Australian stormchasers

hello Jimmy and Brad
it was a funny and very pleasant instant to meet you in Murdo ;)

i'm the frenchy with Dean GILL french/swiss team (4peoples)
do you remember our second encounter in the road (south of Limon the 29 may?

this day just one good storm near Lamar:


our position:


see you soon les amis de l'autre bout du monde ;)
Vincent ("fryz")
« Last Edit: 10 June 2007, 07:01:15 PM by Fryz »

Offline Jimmy Deguara

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Re: May 25 - 29, 2007 - Tornado Alley
« Reply #9 on: 11 June 2007, 03:06:54 AM »
Hi Fryz,

We remember you - a lot of fun on those storms - unfortunately the storms became outflow dominant

Just a little caution: please be careful when overtaking semi-trucks:) Also I am not sure if you recongised the cop, but we pulled aside and the cop stopped near us - so i guess it saved you guys.

How did you go on the 31st May event? I know you guys were flying out on the 1st June?

Can you post images of the supercell you got on the 28th in South Dakota when we let you go and went south?

Regards,

Jimmy Deguara
« Last Edit: 11 June 2007, 03:14:10 AM by Jimmy Deguara »
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