Topic: May 19 - 23, 2007 - Tornado Alley

[Macca]

Hi all,

Just a quick one. Sitting at the "Sleep Inn" in Billings, Montana at the moment just waiting to see how things unfold. There is a near-stationary front aligned east/west across this area with (*some*) moisture pooling around this area with DP's in the low 50's (struggling...). Shear is actually quite nice today N of the front with 850mb winds of 20-30knts from the E. Later today, an upper level shortwave trough is forecast to move over this area bringing 30-35knt SW'ly winds in the mid levels.

There is already convection firing on the ranges to our SW which should move up over this area in the next 2-3 hours. Lapse rates are very steep today with 8.5-9C/km over us from 0-6km! LI's are in the -6 to -7 range and CAPE is approaching 2000j/kg so there should be some fireworks this afternoon. Supercells are likely, however, these will probably be elevated given the low moisture levels but large hail and damaging winds are likely. There is a slight chance of a tornado but again this is very very slight due to the low moisture levels.

Tomorrow looks slightly better with DP's into the low-mid 50's and a surface low over NE'ern Wyoming resulting in backed surface winds over NW South Dakota. SW'ly upper level flow over the region should see supercells develop with the chance of tornadoes.

More later. (Great lightning show last night after spending the day sight seeing in the Black Hills Forest in South Dakota and also Devils Tower in NE Wyoming).

Macca & Chris (and others).

[Jimmy Deguara]

Thanks Macca,

Here are some quick pics from the Montana chase 19th May 2007 - Macca can do the usual blurb of our chase.

After the weakening cell, these storms literally exploded along the boundary and developed at least one though probably more separate mesocyclones (need to verify via radar)



Suspicious bases beneath two strong updrafts. All photographs taken near Roundup, Montana.




Another updraft and suspcious base


Lightning on the way to Miles City, Montana - one of the lightning pictures from a short shooting opportunity



Full photo set here:
http://australiasevereweather.com/photography/photos/2007/jd20070519.html

Regards,

Jimmy Deguara

[nzstorm]

Watched a nicely structured storm from hwy212 far Northwest Wyoming lat night with Michael Thompson. Highlight of the day though was watching the cowboys at the Bucking Horse Fair at Miles City, Montana. Real heartland America stuff. 
Another messy convective day over the great plains instore today. Tomorrow could be interesting in SW Kansas.

[nzstorm]

The storm over far NW Wyoming last night. Quite a nice show.

[Jimmy Deguara]

Macca may copy a detailed post in this thread.

In general, the previous day's cold outflow impacted on the majority of southern Montana. Starting the day in extreme eastern Montana, we dived south obviously missing the supercell coming out of Rapid City, South Dakota. But that was not our target. We stopped for data at Belle Fourche South Dakota and decided that the extreme eastern Montana/Wyoming border region was the most interesting.

Setting out along I-90, we headed west in the direction of Gillette, Wyoming. As we neared, we stopped on a hill to observe some nice sructure. My interest lay in an interesting feature to our west - beaver tail? Whatever it was it deserved investigation. As we decided to head towards it - a tornado warning was issued. Unfortunately, this region is a radar hole and the tornado warning was issued based on a tornado report. We got to Gillette as the base passed over. No tornado but it did coincide with a nice updraft. The mammatus was quite nice - Andrej was besides himself with these 'sky boobs".

Some pictures: (Click thumbs for enlarged images)

Inflow feature


Merely a picturesque scene - distant inflow more interesting


Mammatus near Gillette, Wyoming



Full photo set here:
http://australiasevereweather.com/photography/photos/2007/jd20070520.html

Regards,

Jimmy Deguara

[Macca]

Hi all,

We are in Lusk, Wyoming. Started the day in Glendive, Montana. We decided that the cold pool from the previous day's storms had pushed farther S than progged and as such, we figured that most of Montana would probably not recover properly. So we decided to head for northern Wyoming closer to the boundary (warm front). We headed down to Belle Forche and then towards Gillette from there as storms exploded along this boundary to the S of Gillette. We got within decent viewing distance of the main cell which became tornado warned and then pressed on to Rozet and then Wyodak where we encountered some small hail (to 2cm) and a decent barage of *CLOSE* lightning (should have some crackers on video!). We went to Gillette but by this time the storms had already developed into a pile of crap.

The problem with the last two days has been that storms have not developed/aligned themselves to utilise the favourable shear. Both days, this has been a result of convection exploding in lines/clusters as opposed to isolated cells. As these lines/clusters interact with each other, they lead to their own demise, whereas more isolated cells can utilise the environment (shear) around them and generally last longer.

Anyways - we finished our chase just N of Gillette as the lightning show moved off to the NE. We checked data and ate and decided that we could get some time up our sleeves for the next day by dropping S 100mi or so. We are staying in the same place we did a few nights ago with the plan of playing SW SD or the Nebraska Panhandle today. The Black Hills have fired every day for the last 3 days (relatively early each day thanks to the elevated terrain) and we figured tomorrow will be no exception.

Fairly tired after a deer-filled drive from Gillette to Lusk last night. (The funniest part of which was when we were driving through the town of Newcastle and 5 or 6 deer had wandered in to town and were feasting on the fresh green grass out the front of the city hall).  Eventually got to be at about 2am (after checking more data...hehe...).

Pics to come sometime...lol.

Macca & Chris

[nzstorm]

Hung around Rapid City area for a good part of the day.  Thought we would watch for anything interesting firing on the cold front. But dp's had dropped to 7C!  Interesting to see the very high based blow ups though.  We don't get elevated convection in NZ. Observed 1 inch hail and some impressive CG's.  Currently heading for Valentine, Nebreska. 

Looks to be a reasonable chance of a tornadic supercell or two tomorrow anywhere from SW Nebraska to SW Kansas. Will pick our target area in the morning. 

[David C]

Tomorrow looks very tricky in some respects with the main upper level wave remaining well north and west of the unstable air, although, it looks to be a potentially very good chase day nonetheless with chasers spread far and wide! At the moment, I'd reckon the eastern fringe of the decent 500mb flow, somewhere in south western Kansas around Dodge City, might be optimal for a 'few' dryline tornadic supercells. Although height falls are not significant, there should be some good heating and sufficient moisture over the region which hopefully will allow a few isolated storms to develop. Such storms on or south of the triple point would be in prime position to produce tornadoes in the evening with very favourable low-level flow in place. I'd be wary of the cold front further north into Nebraska despite the better 500mb flow there as outflow dominant storms might be favoured. Oh well, good luck everyone.....could be a classic boom or bust situation !!

[nzstorm]

 I think I would rather have the boom or bust scenario in SW Kansas than the cold front in Nebraska. Have seen enough linear storms of late.   Got one just out to the west of here tonight.

[Jimmy Deguara]

Hi,

Nothing much to report except more or less re-positioning. I guess a few pretty pictures although none of the few gustnadoes and small hail we observed as we dropped south to Goodland. I would have preferred to chase at least northern South Dakota or North Dakota though the drive would have been exhausting. We side-lined the squall line from northern Nebraska to southern Nebraska east to Ogallala, Nebraska.

Macca and Chris dropped south first given their quicker fast food stop and chase, our group remained for a nice sit down and dine meal in Ogallala. Fantastic - finally we get to set down and simply relax, reflect - until

"Ok everyone move into the hall way - now".

"What?" Everything happened too fast.

Tornado warning!

Brad and I were out the door in a flash (perhaps leaving foot tread marks in the carpet)  followed by Esa and Andrej - I must admit we did hear the lady's voice in the background - "No - move into the hallway".

We tried to video the appoaching squall line for signs of any funnels amidst the blazing sirens but nothing we could see took our fancy. But it made the meal interesting - two of the guys first tornado siren:) Oh and by the way, the lady who was so safety conscious was outside taking a smoke break during the ordeal! We did go back in and sat at our table once the rain commenced - she got us the second time.




Storm near Ogallala that interracted with the squall line:


Full photo set here:
http://australiasevereweather.com/photography/photos/2007/jd20070521.html

We caught up with Chris and Macca in Goodland at our pre-booked rooms. Thanks Chris and Macca once again.

Regards,

Jimmy Deguara

[Macca]

HI all,

Currently in Wakeeney, Kansas with a multitude of other chasers and chase vehicles more decked out than you can ever imagine.  We are playing the cold front/dry line triple point today and the storm has developed about 30mi to our SW and is moving NE towards us.  It only developed about 20 minutes ago so we are going to wait here for it to become more established and to identify the best intercept position (it will likely move ENE or even E when it really gets going).  There is a tornado watch box for this area with a 10% chance of tornadoes.  There is a chance they will upgrade this area to moderate risk in the afternoon update (due out in about 30 minutes).  We are all quite excited for today and tomorrow as they are both looking like good tornado producing set ups.

Macca & Chris (& Jimmy, etc)

[David C]

Very nice tornado-warned cell just to the north of Wakeeney at the moment - 6:50pm CDT. This storm is also being warned for tennis ball sized hail (in St Peter).

edit: A few tornadoes were reported today, but it is tomorrow that looks like a classic setup for Oklahoma and also Kansas!

edit 2: Wow, seeing some incredible examples (photos) of supercell structure in these Kansas storms on ST!

[Macca]

Hi David and others,

I haven't checked ST yet but I guess the photos are similar to ours.

We started our day in Goodland, KS and knowing we were within 3-4hrs of whatever target we picked for the day we did some washing this morning. After a data check during washing, we decided that we'd play with the triple point in north central Kansas.

From Goodland, we headed to Wakeeney where we fueled up and gathered more data at a hotel (WIFI) along with a number of other chasers. That was when I posted my first post. We left Wakeeney shortly after that and headed west to Collier where we basically sat and watched the storms develop to our SW and move slowly NNE in front of us. Various storm splits later, one updraft became severe and developed nice supercellular characteristics. It had some nice base-level rotation and produced at least one if not several funnels. Whilst this was happening, another storm was developing to its near SW. As the first cell moved off to the N of us, the next cell went crazy with awesome rotation. A nice RFD unloaded and the base rotated viciously for a while before it moved off to the N also. We watched from just N of Collier for a while before we started to lose sight of it so we raced back east to Wakeeney and then N. We went about 3-4mi N (amongst dozens of other chase cars) and that's where we saw the (now confirmed) tornado. It was a nice cone tornado which we got some low(ish) contrast video of as we drove N towards it. I believe some others may have some very nice, high contrast footage of this tornado [Wink] .

We watched this area occlude and another meso wrapped up to the east of this (it was quite hectic at this point). On top of this, another line of updrafts were exploding to the SW of these ones just to the SW of Wakeeney. With only dirt road options east, a hail core north with 2 inch hail reports, we decided to head back S to Wakeeney to play with the new stuff. This area just exploded and within 20 minutes, we were looking at yet another AWESOMELY structured supercell. Things became somewhat linear from this point on, however, it was moreso a line of embedded supercells.

The entire day saw incredible low level inflow with consistent 30mph SE'lys although at times, when the storms really started cranking, it would pick up to 40mph with gusts approaching 45mph.

The line progressed slowly eastwards and developed rapidly to the SW along the frontal boundary as evening approached and we just jogged ahead of it and stopped for photos a few times. We randomly met up with Jimmy, Brad, Andrej and Esa who were all wet and filthy dirty for some reason [Wink] . Another few jogs east and we found ourselves heading in to Hays, Kansas and to our surprise, the tornado sirens were blaring. Well...I guess it wasn't really a surprise with several areas of the line showing up potential for tornadoes, however, the linear nature made it a little less likely they would occur. A quick look at things saw us decide to bunker down in Hays and wait the storm out. We had positioned ourselves just out of the tornado-warned area (we were on the S side of Hays with a doppler-indicated warning for the N side of Hays). We found some shelter from the car in a disused diner and waited as the beast approached. Over the next 30 or so minutes, we were slammed with unbelievably heavy rain, CRAZY lightning, hail up to about 2.5cm (which was being blown sideways so that it was hitting most of the car anyway) and winds that were just amazing. Hays reported a wind gust of 80mph during the storm. During one minor lull, I decided it would be a good idea to shoot some footage from outside of the car...I spent the next 15 minutes cowering beside an SUV for protection as another barrage of wind, rain and hail hit us. The river that used to be the road we were on right beside us was raging along nicely with bits of debris floating past and hail splashing into the water.

Eventually it let up and we headed off to find accomodation.

All in all probably one of my best chase days! Tornado, hail, winds, rain, sirens, and AWESOME structure.

And as Will has mentioned, more of the same tomorrow!

Some pics from today are here...I haven't done anything with these yet - they are straight off the camera.

http://macca.bsch.au.com/gallery/20070522

Macca & Chris

[David C]

Wow - what a plains classic, Macca! Congrats to you guys that is just magnificent structure and tornado. All the best for tomorrow as well, it is looking very good again.

[Jimmy Deguara]

Hi all,

Macca thanks for the description. I guess we were there from prior to the storm being severe warned. We do have the same supercells from a different perspective. Everything was ok up until the tornado. After tornado - we got bogged but with hard work we got ourselves out! I was the driver, the rest got dirty. One must take care of the captain haha.

Anyway, to say that this structure is some of the best I have ever seen is not an understatement - well I will let the pictures tell the story. Strangely enough, I had a dream that I observed a tornado - one could not believe that it came through!



Full photo set here:
http://australiasevereweather.com/photography/photos/2007/jd20070522.html

Regards,

Jimmy Deguara