2015-05-09 EVENT: TX/OK/KS/NE/CO

[Stan Rose]

I 'chased' from the warning desk at PUB. Watched a rapidly rotating wall cloud and funnel cross just SE of our office; this tor-warned sup eventually produced the tornadoes near Ellicott CO,
unfortunately it also put numerous dents in my brand new OB from the golf ball+ size hail that fell here. I could only helplessly listen as the pounding commenced, and the phones were ringing off the hook...hail was to baseball size just up the road. Oh well, guess I don't have to worry about dents in my new car now... Then I warned on the storm in Kiowa County which minutes later ended up producing multiple tornadoes from Eads and beyond. Fellow ST member and PUB met Kyle Mozley was on that one and got some good pics, along with numerous other chasers so im sure there will be many pics to follow... I think we'll be posting pics of the wall cloud on our FB page in a bit. Meanwhile...10+ inches of snow just up the highway in Teller County and about 6+ over Monument Hill north of COS. We may even get some snow tomorrow..Plus massive river flooding. The CO plains are going to be very green this spring...should help with dews!

 

[Jeff Duda]

This event has bust potential. Veer-back wind profiles across much of the DL in OK. I've never had a good day when dealing with S-shaped hodographs. They lead to messy storms.

The veer-back has been consistent in both the GFS and NAM.

The biggest thing that worries me about pretty much all days this week, including Saturday, is early development of precipitation/convection across a widespread area covering the target. The GFS has been consistently developing precip between 15Z and 18Z up and down the dryline. This just kills the surface temps and really keeps instability pretty low. If that much precip really does overspread the warm sector and minimize sunshine and destabilization, I suspect this event will be pretty spotty and marginal.

FWIW, the 00Z MPAS forecast shows MCSs originating in almost the same area (eastern TX PH/NW TX/SW OK) in the late-morning to early afternoon three days in a row, starting today (Thursday) through Saturday. Today's forecast appears to be verifying, although the MPAS forecast was a few hours late in initiating the MCS. These MCSs totally wipe out the CAPE during peak heating and the atmosphere never recovers. As @Jeff Snyder mentioned, the timing of early CI will make a big difference.

I have also noticed the veer-back pattern slowly fading away or being limited more towards 500 mb than before. However, as I said before, this day still has bust potential. The large scale pattern certainly fits an outbreak, but the devil is always in the details, and those details matter.

Man I hate having been right about this. However, this illustrates that even the GFS did a pretty decent job even on some mesoscale details with this setup. Just goes to show you that you shouldn't ignore a 3 or 4 day precipitation forecast of convection just because you don't like it.

And props to the MPAS model for strongly indicating the early MCS blow ups each day Thursday-Saturday. I'll be paying more attention to this model in the future.

 

[Eric Bucsela]

Man I hate having been right about this. However, this illustrates that even the GFS did a pretty decent job even on some mesoscale details with this setup. Just goes to show you that you shouldn't ignore a 3 or 4 day precipitation forecast of convection just because you don't like it.

And props to the MPAS model for strongly indicating the early MCS blow ups each day Thursday-Saturday. I'll be paying more attention to this model in the future.

Jeff, true but what about the models' early precip and veer-back predictions for the northern target? To me those looked at least as discouraging yet the storms were classic, plentiful and chaseable. Did I misread the forecasts?

 

[Jeff Duda]

I didn't pay any attention to the CO/KS part of the forecast because I knew I was never going to chase there. So honestly I can't comment on that.

 

[Taylor Wright]

I'm a noob, but holy cow. I thought I at least knew a little about forecasting until this day. We were running around like chickens with our heads cut off with no idea what to do then we end up getting a bunch of tornadoes after dark in Kansas in 60 degree temps and 50 dews (Good call Shane). Ugh. How discouraging.

 

[Caleb Grunzke]

Jeff, true but what about the models' early precip and veer-back predictions for the northern target? To me those looked at least as discouraging yet the storms were classic, plentiful and chaseable. Did I misread the forecasts?

The northern target (northern Kansas and southern Nebraska) didn't have the veer-back winds while southwest Kansas (where the moderate risk originally was) did. And as you saw, not much happened in southwest Kansas.

 

[Stan Rose]

The northern target (northern Kansas and southern Nebraska) didn't have the veer-back winds while southwest Kansas (where the moderate risk originally was) did. And as you saw, not much happened in southwest Kansas.

The VBV in SW KS was subtle at best, and I think it had little if anything to do with the lack of tors there. The 00Z DDC sounding actually looked OK.

I didn't pay any attention to the CO/KS part of the forecast because I knew I was never going to chase there. So honestly I can't comment on that.

Well that'll teach you to ignore my state lol, it was a top career chase for those who picked the right target. Some of the best photos of tors I've seen, kills me I had to work it (and suffer a destroyed brand new car as a result). Kudos for recognizing quickly how convection would ruin the huge potential in OK/SW KS, but this was still a pretty good regional outbreak, one of the best we've seen here in my CWA. Definitely not 'spotty or marginal' With 53+ tor reports, can't imagine how many there would have been without all that CAPE destruction...

 

[Dan Robinson]

Anyone who's chased or has seen results of past chases in Colorado knows to not ignore a deep surface low up there with great upper support, even with 50+ dews. High Plains magic. That said, it is somewhat rare for one to produce as efficiently this one did. Texas was a viable target for anyone already down there facing the long drive to Colorado (IE, 2,000+ CAPE with 50+kts bulk shear, boundaries and a secondary surface low in N Texas). I'm quite surprised at the Kansas storms' ability to get it done with that kind of moisture, I believe that is truly rare for a May event with 50F dews to be that efficient in that area.

 

[Chad Alcares]

I fully agree with Dan. That chase in Colorado was a career chase for a lot of us for a reason. It just doesn't happen so perfectly that often. This was one of those where if you did start your day in Western KS, southwest KS, even far northern TX and OK panhandle you had time to get out there... if you identified what was or was not going on. And - you had to be persistent... you had to have faith that the cell that started in Southeast Colorado that was never severe warned, as it was never severe warned until Eads if I recall, was the storm that had to be followed. It wasn't the best looking thing early on - but its isolated and anomalous flow (in comparison to other showers/storms in region) kept us targetting it.

Full disclosure - I wasn't expecting to seeing a couple long lived supercells putting down multiple wall clouds and tornadoes, more expecting of well the original target in the warm sector is shot - we have to go to the low for any chance at a tornadic storm. Luckily - my friend and chase partner is of a similar mindset - saw the pattern... has been following weather as long as I have - most importantly knows that the pattern can produce - willing to gamble on a long long drive. You follow severe weather long enough and these stick out... normally this play is a secondary target - but in our mind on this chase it was the primary, mainly with the lack of recovery soon enough in SW Kansas. I'm not going to try and figure out why it didn't - I just like where we were.

This was the kind of chase in this hobby that sucks you in, makes you want to come back and do it again. Very similar to our 2011 Bradshaw tornado chase and my June 2012 southwest SD - Ardmore, SD chase. It takes full commitment (especially when driving 8 hours to target) and when it pans out it's like hitting your driver 250+ yard drive down the middle of the fairway - not just once but over the entire 18 hole course, or landing multiple 20+ inch largemouth bass in a day of fishing