Chase Log: June 19th, 2007
Click on any of the SPC products below (Convective Outlooks, Watches, or MCDs) to see the SPC's "Severe Thunderstorm Events" page pertaining to this event.
Total Distance: 520 miles
Target Area: Liberal, KS
Chase Area: Near Woodward, OK
Maximum SPC Risk category: Slight
Watches:
Mesoscale Discussions (MCDs):
Extreme instability developed this afternoon south of I70 across western Kansas, Oklahoma, and the Texas panhandle. With temperatures in the 88-93F range and dewpoints in the 75-77F range, MLCAPE >6000 j/kg and a weak cap would support very intense storms. The best flow aloft was north of the OK-KS border, and even that was rather marginal at ~25-30 kts. Despite this, southeasterly low-level flow helped develop 30-35kts 0-6km shear in Kansas, and 25-30 kts 0-6km shear in Oklahoma. I headed up towards the Oklahoma panhandle knowing that a nearby boundary (an OFB from previous convection) might combine with the extreme instability and marginal-but-hopefully-sufficient deep-layer shear to yield a significant supercell threat.
A tornadic supercell developed rather early in the afternoon northwest of Hill City, but the primary uncertainty farther south was initiation. The RUC and NAM forecast a subtle vort max approaching the OK/KS border area by 00z, and water vapor imagery indicated an area of drying aloft entering eastern Colorado by late morning. I waited around the OKC area, flip-flopping on whether it would be worth the drive. About 2 pm, I hopped in the car and started the drive towards the Liberal KS area. By the time I reached Woodward, DDC was showing a couple of towers developing near Liberal, with more convection exploding to the east, closer to Enid and Alva. Banking on the verification of several RUC forecasts of best low-level shear staying in the panhandles area by evening, I continued northwestward towards the developing cells. However, by the time I reach Gate, OK, all I saw were a couple of turkey towers and an huge orphan anvil. Ouch. I made it as far west as Forgan before stopping to look at more data. A couple of storms were developing up by Garden City, and the huge HP supercell continued to march southward to the northwest of DDC. I temporarily opted to see if I could catch those cells, but opted to stop my northward progress when I reach Meade, KS. Since I was chasing solo, and I was already several hours from home, I didn't really want to continue northward in hopes of reaching the supercell before it transitioned to an outflow-dominant MCS. With convection continuing to develop rapidly to my east and southeast, I started to fold up the cards...
The outflow boundary / gust front surged westward from the mass of convection over northwestern and northcentral Oklahoma by the time I made it back into Oklahoma. Ugh. The extreme instability was continuing to support severe thunderstorm development along the edge of the outflow, however. As I approached Woodward from the north, I experienced blinding rain, ~1.0" hail, and strong winds. All of these slowed my southward progress to about 20-30 mph for a good 30 minutes. I eventually drove out of the hail, but the rain continued pretty much the entire way until near Kingfisher. I made it home by midnight, with at least a little smile that I caught some severe action in and around Woodward. Sure beats a cap bust.
