2011-06-14 REPORTS: NE/KS/OK/MO/AR

[Jeff Snyder]

Dewpoint depressions were very high yesterday, low-level shear wasn't particularly strong, but the latter, along with deep-layer shear, were sufficient to support storms with "supercell structures". The initial thunderstorm developed W of Norman, and we deployment near the OUN airport. Dan D. and Robin T. joined us at this location.

Approximately 5 minutes into our data collection efforts, we noticed a developing microburst to our immediate northwest. CG activity was quite frequent at this time, and we deployed with the front of the truck facing to the east. As such, I wasn't able to take any pictures during this time. At any rate, very strong winds soon slammed us, and we were blasted by ~1" hail that sounded like machine-gun fire. For the next ~80 minutes, we collected data as this original storm, and subsequent convection, moved through the area. As we all know by now, the nearby Norman mesonet site measured 70 mph wind gusts, though we have slightly stronger winds in our data (usual caveats: these are nearly-instantaneous observations, etc.). We were treated to some fantastic stormscapes, though, with nice rainbow and double rainbow activity to our east.

A few pictures:

 

[Patrick Marsh]

I witnessed these storms from the observation deck of the NWC. At the NWC winds were in the 50-60mph range, but the core of the storm remained to our north and then east. I know that at least one OU Meteorology Professor measured winds of 82mph with an at home weather station before the wind driven hail rendered it trash. I've also seen YouTube video from the home of a NSSL researcher and it appears that winds there were also in the 80-90mph range.

There is a lot of damage to the north and east parts of Norman, but after touring the damage last evening, one thing that caught my eye was that most of the damage is confined to areas where people are. Homes, businesses, utilities, and landscaping took the brunt of the damage, but areas that were relatively open had minimal damage. Thus, I wonder what role channeling of the winds played in enhancing the microbursts locally?

 

[James Hilger]

In NW Arkansas in particular Bentonville, we had gusts im guessing 85+ and it snapped poles, caved in garages, and made some streets impassable with all the debris. It was like a fireworks show with all the transformers blowing. I had to slow down to around 30 while driving to stay in control and eventually decided to pull over so i could face into the wind. (I was driving South and it was coming from the West).

 

[Jesse Risley]

I decided to play the more synoptically favorable target for tornadoes in MO on Tuesday. We picked an initial target of Cameron, MO, as numerical models were initiative convection ahead of the surface low/trough by early evening, despite the warm EML present across the region for much of the day. Initial convection closer to the IA border looked to be trying to go linear rather quickly, and no cells appeared to be interacting with the warm front, so we opted to stay south and keep an eye on towering Cu fields near the US 36 corridor. A few cells went up near Chillicothe, MO, but struggled to remain intact, possibly due to some residual CINH further south. However, initially elevated cells formed to the south ahead of the trough, and one cell apparently became surfaced based, rooted in the boundary, interacted with either the WF or a remnant OFB and produced a surprise TOR that I witnessed near New Boston, MO. The tornado was on the ground for 4-5 minutes and was clearly visible, despite the darkness and poor terrain. A full chase report and video available here.

 

[Travis Wilson]

I watched the downburst come into NE Norman from a hill on Tecumseh 1/2mile west of Rock Creek. The pictures below are looking west toward the Sysco plant. Nice slowly rotating elevated wall cloud. As the rain foot developed and kicked out to the southeast, I was able to observe the precipitation making an incredible leading-edge upwards barrel-roll. I could literally see the bands moving upwards and then rolling over back to the northwest before falling down onto the rain foot. I tucked my car right behind a building when the hail started, and a few minutes later the wild horizontal wind and pea-sized hail and rain hit. I think it was every bit of 70mph for half a minute or so.
Lots of destroyed fences around Rock Creek and Tecumseh. Similar to last year’s Norman microburst, I was surprised at how slow the system moved despite the crazy winds. Several minutes after it blew through my position, I was able to drive back into it just a mile away