Chase Log: April 21st, 2004
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: 400 miles
Target Area: Pauls Valley, OK
Chase Area: Norman to east of Ardmore, OK
Maximum SPC Risk category: Moderate
Watches:
PDS Tornado Watch 98, Tornado Watch 101, Severe Watches 102 and 103
Mesoscale Discussions (MCDs): 407, 413, 417, 420, 421, 423, 424, 425, and 426
Well, I had a dynamics exam at 3:30-4:30, so I was worried about getting a late start. By the time we packed up and hit the road, the OKC supercell was already in the city... We started driving north to that cell, but saw a nice storm just to our south (southwest of Norman). So, we turned around and headed for that storm. Stopped near Purcell to watch a couple of nice, very low wall clouds. As it crossed I35, we decided to ditch it because it appeared to be outlfowing out, and the fact that there were cells southeast of this one lead us to conclude the the southern one would disrupt and cut off inflow. So, we headed south then east then south. Drove through a couple of hail cores with mainly small hail (1"). Got some nice pseudo-wallclouds east of Dougherty in Murray county. There were probably 2 actuall wallclouds, but there were numerous other features that looked very much like wallclouds but later appeared that they weren't connected to the cloudbase. Hmm... By this time, the structure was really puzzling to me. The updraft base had a sort of upper-case Omega shape, which strongly rotating clouds in the middle of it. Really wierd. Whatever the case, the sun started getting low, so we knew time was running out. Got wind of the tornado warning for the supercell in Marshall county, so decided to just try for it. By the time we got to Madill, though, the storm appeared to have weakened and the tornado warning was dropped. Since the sun had set, we headed west to Ardmore for some food....
Overall, this was a PDS chase... Particularly Disappointing Situation.... Despite incredible low-level shear and strong instability forecast by the RUC, it seems that we just had too many storms in the area that all ended up competing for each other. Additionally, the forcing seemed too much for the minimal capping to keep storm really discrete...
We are STILL feeling the affects of the front that went through the Gulf about 10 days ago. Who ever would have thought that it'd take almost two weeks for the gulf to completely recover from a single fropa.... Oh well...
04-21-2004 Chase Pictures
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