Chase Log: April 23rd, 2003

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.

MAP

Total Distance: 500 miles
Target Area: Seymour, TX
Chase Area: Altus, OK, to Throckmorton, TX
Maximum SPC Risk category: Moderate
Watches: Tornado Watches 146, 149, and 150, Severe Watches 147 and 152
Mesoscale Discussions (MCDs): 542, 544, 547, 548, 550, 551, 552, and 553

Yet another potentially significant severe weather outbreak forecasted for the southwestern OK and northcentral TX area. Moisture return and convective debris from morning convection were the main concerns going into the day. These concerns, in addition to almost no cap/CIN forecast by the ETA by early afternoon, led me to enter the day rather hesitant. The SPC and NWS seemed optimistic about the situation, however, and thus we could not pass up a high-shear day.

Myself, Paul, James, and Jen left Norman about 11:30, heading for the intial target of Seymour, TX. We stopped in Lawton so James could get some cash and so that we could take a look at the latest data. While my internet connection was misbehaving, we were receiving word that storms were already going up off the dryline and approaching western OK and western north Texas. By the time we hit Vernon, we got word that a nice, rotating supercell was just to our south. Initially, we were a little weary, because of the storm motion and speed, we would end up punching the core. However, both the speed of my car and the storm made it such that we avoided this situation. We approached Seymour and notice a very nice supercell to our west. After dinkering around trying to find out the best route and approach the storm, we finally got a good view of the very impressive meso. However, it looked as if the storm was becoming increasingly outflow dominant. We were able to get some pics and connect to the internet, at which time we saw that our storm was completely falling apart. A storm further south of us in Throckmorton county had been tornado-warned for quite some time and was disrupting the good inflow that our storm had. So, we decided to give up on our dying cell and head southward towards the Throckmorton storm. We stopped in some small town to get gas and take a quick break, when we heard across the ham radio that a hook was starting to develop on the nearby storm. We booked out of the town, thinking we were nearing the storm. Somehow, we ended up going northeast towards Wichita Falls. As we neared SPS, we heard of a tornado on the ground near Grandfield, OK (just across the border). We headed north out of SPS towards the tornadic storm. As we neared the TX/OK border, it was quite apparent that this storm too was falling apart rapidly. This was confirmed minutes later as the NWS OUN cancelled the tornado warning. Hearing the issuance of the tornado warning and the fact that the dryline was still out between Hollis OK and CDS TX, we decided to stop at Whataburger just out of (or in the extreme northern side of) SPS. Upon eating and checking more data, we decided to at least drive through the barely-severe storms that were developing rapidly in a SW-NE fashion right through SPS. So, we drove through SPS and realized that it was time to start heading home. Wanting to follow these storms home, we chose hwy 7 out of SPS. We encountered small hail (perhaps to 0.5") just outside SPS, and we saw some very ominous, low-hanging clouds, which we first though to be tornadic in nature but quickly realize they were outflow-related and we actually just scud. As we neared the OK-TX border, we got wind of a tornado warnign for Stevens county. We busted northeastward to see if we could intercept, driving through more heavy rain and hail. As it turns out, we could never really cath up to the tornadic circulation, although we were within miles of it. We eventually made it back to Norman around 10:40pm.

Another potentially significant day that just didn't pan out. The lack of a cap meant that instability could not gather enough for any real persistent updrafts. Bad timing of a wave around noontime helped initiate widespread thunderstorms early in the day across much of the target area. Additionally, the 850mb jet axis was further eastward than originally forecast and thus the best shear was into central OK (as compared to western OK and western north Texas. I hope this pattern changes, as this "low cap, LOTS of forcing" scenario is getting rather old rather quickly. Three days of significant potential and three disappointments. We did get good structure shots of the Seymour, TX, storm though.