Chase Log: April 10th, 2005


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
(ZOOMED)

Total Distance: 450 miles
Target Area: Waurika to Ardmore
Chase Area: Dibble to Norman to Wellston
Maximum SPC Risk category: Moderate
Watches: Tornado Watches 141 and 146, Severe Watches 143, 145, and 147
Mesoscale Discussions (MCDs): 536, 538, 541, 542, 543, 544, 546, and 547

One of the most difficult chase forecasts I've been faced with so far in my chasing career. Another day of modified Gulf air courtesy of a scoured Gulf. Models had been showing another cuf-off passing through the area from the west. A dryline was progged to stretch southward from a surface low in southwestern KS or northwestern oK by afternoon, with low 60 Tds east of I35 in OK, and mid-60s Tds just south of the Red River. With strong flow aloft, 45-55kts of deep-layer shear along with 1000-2000 j/kg CAPE would support a pretty good chance of supercells. With backed surface flow ahead of the dryline, low-level shear would otherwise be pretty good if it weren't for the fact that we'd have deeply meridional flow on the east side of the low at all levels. At any rate, I thought about the area immediately ahead of the surface low in southern/central Kansas, but I couldn't turn my back on the higher dewpoints streaming northward from central and southern Texas. The NAM was showing, however, the deeplayer shear vectors most normal (least parallel) to the dryline near the Red River area, so I kept my hopes for discrete activity in this area.

The 6z Day 1 outlook issued early Sunday morning highlighted a MDT risk in eastern OK/KS and northeastern TX. This all looked good, until I awoke Sunday morning and checked the visible satellite. Ugh -- there was widespread stratocumulus clouds east of the dryline. In addition, the 12z FWD sounding showed a very stout cap in place. Still hoping for clearing, I left OUN around 11:30am, heading for Ardmore, and driving through light drizzle on the way.

I made it down to ADM by about 1pm. I noticed clearing to the west, but winds were veering along a small-scale dryline bulge it appeared. So, I opted to head back north on I35 to place myself on the northeast side of the mini-bulge as it appeared to be. Well, being in mist and low clouds near Davis in the Arbukle "Mountains", and noting clearing immediately along the dryline, we opted to head west towards Duncan. Sat in Duncan for a bit, met up with some fellow chasers (Bryan Burkholder, Kiel Ortega, etc.), and realized that if storms were going to develop, they'd do so either north or south of us. With better moisture to the south, I figured that it'd be best to head south towards Waureka, then east from there. Well, I/we meandered between Waurika and Ringly, waiting some towers go up... and down. There appeared to be more persistent convective attempts to the north, so we slowly meandered north on Hwy 89 and 76 toward Ratliff City. At this time, it did appear that some updrafts were able to take hold to our north-northwest, so we jetted towards Lindsay. I filled up with gas in Lindsay, and we headed north on Hwy 59. Not too far out of Lindsay, a semi-decent updraft base came into view to our west. This storm SLOWLY increased in intensity and organization for the next while. The first wallcloud attempts we saw was some nice rising scud actions south-southeast of Dibble. At any rate, we followed this storm to the northeast through Norman, observing several pretty nice wall-clouds in the process. In fact, there was a pretty big wall-cloud sitting right over central/northern Norman for a while. With the sun beginning to set, the colors below cloud base were pretty awesome.

Despite the wall-clouds, I didn't really see much rotation until the storm neared Twin Lakes. We stoped at the Love's at I40 and Choctaw, thinking we'd watch it roll by before heading back to OUN. At this time, I noticed a very interesting funnel-like feature that developed immediately south of my location (or east-northeast of Lake Stanley Draper). OUN issued a tornado warning at this time, and we headed east on I40 before heading north on Harrah Road. Noting OUN reports on ham about tornado-scale circulation likely to the southwest of Harrah, we opted to jog eastward a bit towards McCloud before moving northward again. I saw numerous power flashed during this time, with the highest concentation as I was heading northward towards Harrah. At any rate, following the tornadic circulation, we headed north on 102, and got as far north as about 8 miles south of Wellston. At this time, OUN was mentioning very strong circulation 12 miles S-SW of Wellston, and a spotter reported a funnel cloud about 10 miles S-SW of Wellston. Hmm... Not wanting to head farther north, we tried to cut east to get out of the way of this thing, but the roads were pretty horrible here... So, we opted to just bite the bit, haul south, and call it a day.

All in all, it was an interesting day to say the least... by interesting, I mean VERY difficult. I was VERY surprised to see that the storm was only moving at 20-25mph, despite the strong mid-level flow.

04-10-2005 Chase Pictures

Click on any photo to see a larger version

We caught up with Michael and Kristen (and a few others) while meandering around southern OK. We're all enjoying the lack of convection... right... This was a random church that looked a little shady, but had a large front parking lot area that gave us a good spot to stop and wait for initiation. We raced towards this "storm", which appeared more like a tilted TCU than anything, and we able to catch up to it just north of Lindsay. A couple of interesting features began to reveal themselves quickly at this time. Another shot of the highly-shear TCU. Haze was pretty thick, and I didn't have a haze or polarizing filter to help the contrast issue. Again, some contrast issues from the haze. Note a slight cloud tag hanging beneath the latest convective "updraft burst"... This wallcloud developed as the storm moved to the northeast noth of Lindsay and near Dibble. We followed the storm as it moved northeastward towards Norman. By this time, the storm had matured a bit (compared to the highly-tilted, no-anvil Cb that it had previously been), and a nicely lit, large (yet not entirely threatening) lowering developed. Here's an out-the-window picture I shot while driving (thus the bad framing and blur). Note the wallcloud nearing the location of the OU dorms and football stadium (lower-right). A decent wallcloud had persisted as the supercell traversed over Norman. This shot was taken near Hwy 9 and 24th Ave NE. For the record, the wallcloud is very near (though a tad north) of my apartment, which is a couple miles north of this location.