The Texas Panhandle Wonder - 25th May 2018
The 25th May mostly involved a long drive south from Hays, Kansas, as storms were expected to initiate in north-west Oklahoma during the late afternoon. With a subtle surface low in place across the Texas Panhandle, intense surface heating was expected in NW Oklahoma and just over the border into Texas. Storms were expected to fire here, with a few decent hours of chasing anticipated, before the storms merged together into a quasi-linear convective system. Thus, we had hopes of seeing similar structure to the previous day - perhaps a nice shelf cloud with photogenic lightning. What we ended up seeing couldn’t have been more different. 
Surface weather map, valid for 16:00 (Central Time) on the 25th May 2018. Little synoptic forcing remained in place across the Great Plains, although a shallow surface low across the Texas Panhandle would provide enough forcing for discrete severe storms.
Credit: NOAA/Weather Prediction Center.​

SPC convective outlook issued at 14:52 CDT. A slight risk was issued for the Southern Plains and Wisconsin/Minnessota/Iowa. A 2% tornado risk was also issued for the Oklahoma/Texas Slight risk area.
Credit: Storm Prediction Center.

After blue skies on the journey all the way south through Kansas, some subtle cumulus clouds began developing in northern Oklahoma - always an early sign of potential thunderstorms later. However, satellite imagery revealed a trough line oriented north-south in the Texas panhandle, which was already providing a focus for agitated cumulus, and had already produced a severe storm further south on the Texas/Oklahoma border. After waiting for a short while to determine whether the cumulus field in Oklahoma would produce any storms, the decision was made to head west and chase developing storms on the trough line. During the quick blast west, sure enough a lone thunderstorm developed on the northern edge of a cumulus congestus line. 

After a quick fuel stop, we drove south from north-west Oklahoma and then west a little into the Texas Panhandle, eventually ending up near a place called Mobeetie. We ended up there after driving under the anvil of the rapidly developing storm - which was chucking out positive CG strikes left right and centre. Although there were some great photo opportunities, we didn't want to find out how powerful a positive lightning strike is! Luckily, the low-precipitation supercell produced no rain as we drove underneath what would otherwise have been the forward flank downdraft - involving an inevitable core punch (a manoeuvre we were forced to perform just two days previously).

Close to Mobeetie, we had a great view of the thunderstorm updraft - the storm was strongly right-moving by this point, and we also observed, visually, the updraft splitting several times - which is something we’d never seen so clearly before. We could literally see the updraft base splitting, with the different updraft rotation of the updrafts clearly visible, and the left splits clearly weaker. The storm slowly drifted south towards us, and the view directly underneath the corkscrewing (right split) updraft was breathtaking. Several funnels appeared under the updraft - and some in the mid-levels of the mesocyclone too, which was cool. Add to this backlighting from the late afternoon sun, and the storm took on an angelic white appearance. 
Updraft and rain-free base. The faint white glow of a hail shaft can be see behind the updraft, as precipitation became wrapped into the RFD.
After wating to see whether any tornadoes would touch down (and determining that the storm wasn't tornado-producing material), we raced south to get a more clear view of the updraft (rather than being right underneath it), although by the time we found a good location to do time-lapse photography, the updraft had completely dissipated. Nevertheless, the orphaned anvil produced some lovely mammatus which glowed orange and pink in the fading sunlight. 

Structurally, I'd say this was the best supercell thunderstorm I've ever seen, especially since there were absolutely no other clouds (scud, medium-level, high-level ect...) that were surrounding the storm. We could see the rain-free base and corkscrewing updraft, precipitation getting wrapped into the rear-flank downdraft, the forward-flank downdraft, the cirrus viel of the anvil spreading out above the updraft, and also several funnel clouds extending into the updaft. 

A stunning lone supercell, certainly one fitting for the Lone Star State.


Rain-free updraft (with funnel), as well as forward-flank downdraft with hail shafts.
Rotating updraft, funnel and Sun. 
Super-res reflectivity and velocity for the lone supercell. I-40 runs through the middle of the images. Tilt 1. Credit: Radarscope.