2011-06-11 REPORTS: CO / KS / OK

[Jeremy Jones]

Left my house in North Edmond, and ended up about 5 miles due West of Okarche. I was able to film a gorgeous supercell from one position for almost an hour. It was definitely nice to be able to just sit in one spot and relax behind my cameras and enjoy mother nature w/out having to constantly re-position and trying to find a decent spot to film from.

The first image is from Waterloo Rd. a couple of miles West of Highway 74. Really weird band wrapping around the base of this storm...

Same storm...about 20 minutes after the previous photo...

I decided to let this storm go and head farther West to intercept the storms near the Greenfield area. This is the storm I got to just chill on and let it come to me...

and here's the timelapse video I shot of this same storm but about a mile farther down the road on the right hand of the above photo...

Watch video >

 

[Jeff Snyder]

Although the season was beginning to look like it was winding down for the southern Plains (climatologically, this was to be expected), the risk-reward didn't seem to be there for a long trip in RaXPol to the more obvious target of southern Colorado or far southwestern Kansas. A secondary target seemed more feasible for us -- the models were forecasting a zone of enhanced low-level shear, sufficient deep-layer shear, and moderate instability north of a pseudo warm front across northcentral and northwestern Oklahoma. Since there was a good deal of uncertainty in the forecast, however, Mike French and I left in RaXPol by early afternoon with a "checkpoint" target of Weatherford. Upon arriving, we figured, we could reassess the situation and determine if any further movements would be worth it (from a cost-benefit standpoint).

By the time we refueled in Weatherford, relatively widespread but disorganized convection was occurring across northwestern and north-central Oklahoma. Visible satellite imagery indicated that the environment more than a county or two N of I40 was stableas a result of outflow from this convection, and the moisture to the S of I40 was mixing out as forecast. So, there looked to be a narrow window of opportunity for convection immediately along the outflow-reinforced front to our immediate north. Fortunately, a storm did eventually develop by late afternoon to our immediate west. With an initial northeastward motion, we found a deployment location a mile or two southeast of Thomas.

The storm's appearance improved shortly into our data collection, with a relatively typical, generally high-based supercell appearance. Outflow from convection to our east near El Reno moved through our area, which I figured would probably lead to the weakening and dissipation of the supercell that was now just northeast of Thomas. However, it seemed that the relatively cool outflow that was now undercutting the storm had little effect on the storm. I suspect that the CAPE for a parcel located immediately above the cold pool was sufficient to maintain intense convection, and the 00z OUN sounding indicated that some low-moderate SRH remained for parcels in the 1-3 km layer. Regardless, the initial storm was eventually "munched" was a storm on its flanking line developed and become the "dominant" storm. As this second storm moved slowly eastward, a third storm developed on its southwestern flank, and it too went on to detrimentally affect its parent storm. This happened several times, and the net effect was discrete jumps southward in the areas experiencing the most significant weather conditions (large hail, etc.). Since the storms weren't moving very quickly, and since we weren't expecting any appreciable tornado threat, I opted to keep us at our deployment location during this time. The radar collected 2 hours and 45 minutes of data from our location just southeast of Thomas. The storms showed very nice supercell structure in our radar data (beautiful BWERs, etc.), with some anomalously strong attenuation near the freezing level noted.

All in all, the day lived up to my expectations. Dewpoint depressions were a little too high for much of a tornado threat in this area, and we got the supercell(s) that I was hoping we'd get.