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Storm Chase: April 3, 2008

I started off the day with a rather deep synoptic lecture by Dr. Bluestein about arduous mathematical coordinate transformations of equations into geostrophic space. How's that for a brain teaser? After gulping down a couple Chik-fil-A sandwiches for lunch, I went to prep Craig's car for the afternoon chase. It was rather cloudy, with the sky covered with stratocumulus. It would be nice to see more classic setups soon with mostly sunny skies in the morning. Otherwise, this is getting old.

After the Forecast Verification class was over at 12:45 pm, Craig and David Buckey [referred to as "Buckey" from now on; not to be confused with David Bodine, who, by unanimous vote of the OU student body, will still be referred to as "David"] joined David and I in the car. Our initial target was south on I-35 towards Gainesville, TX. We left knowing that the main limiting factor was the lack of low-level wind shear, with surface winds veered to the SSW across the region. However, surface winds were slightly backed towards the southerly direction south and east of the OK/TX border near I-35. We therefore did not want to go too far west. However, the dryline was setting up well to the west of us, and with clearing observed and a nice Cu field on visible satellite imagery, we decided to head west out of Ardmore towards Waurika on route 70 just as a severe-warned storm fired near the border. We decided to stay put for a while and picked up the $5 footlong sub deal at the Subway in Lone Grove, OK.

After much debate [read: basically tossing a coin in the air], we decided to head back south towards Gainesville, TX. The cell that was west of us did not amount to anything, and due to the...overcast...that we were under, thought it was best to head south, then west towards the Cu field. Unfortunately, there are just a handful of roads that crossed the Red River between TX and OK, so we had to make our navigation choices wisely. A tornado watch had been issued by the SPC at 2:05 pm CDT.

After heading west out of Gainesville on route 82, we decided to intercept a new cell that had formed southwest of Wichita Falls, TX. It intensified rapidly on radar, with a rather significant hail core of 70 dBZ+ on radar. At the base reflectivity scan at 4:16 pm CDT, a rather pronounced three-body-scattering signature could be seen extending radially away from the KFDR radar site.

We drove west to intercept the storm, then turned south and parked just a few miles south of Belcherville, TX on farm road 1816. Looking out to the west, we could see the updraft base of the storm in the distance just south of the downdraft. Winds at the surface were out of the southeast, so we knew this storm had some potential to acquire some vertical vorticity.

As it approached, the base slowly become more and more defined, with striations that began to appear. A faint beaver's tail could be seen to the south and east of the updraft base. Meanwhile, the CG lightning was prolific, so we decided to stay inside our car as the updraft approached.

"I'm afraid my head is going to get hit by lightning," David said as he tried to get a picture with his camera. We tried our best to keep all limbs inside our vehicle. The updraft tower could be seen very clearly to our southwest, illuminated by the afternoon sun. There was no lowering with the mesocyclone, so our assessment of any imminent risk was low, so we decided to stay put.

At 4:45 pm CDT, we were right in front of the updraft base. The intense hail core could be seen to our northwest on the base reflectivity PPI. A greenish hue behind the lowering was visible just north of the mesocyclone towards the downdraft. The storm-relative velocities at base tilt indicated some slight rotation, which we could confirm visually.

Once the hail core passed east of our longitude, we decided to go to some sampling. On our way north, we could see a good whale's mouth to our northeast as the warm air was being lifted above the cool outflow.

Once back in Belcherville, we saw numerous hailstones over 2" in diameter that littered the grass around the roads.

We got out of the car to sample the hail and found a stone over 2.5" in diameter.

Each stone had a different shape - some of which were textbook patterns. There were several with spikes, while others had several concentric rings of translucent ice with varying degrees of opacity.

Most of the stones were well over the size of a quarter.

By this time, another lone storm had developed to our southwest, which was beginning to show signs of organization (KDYX base reflectivity at 5:23 pm CDT), so we rushed towards it. There was no point in staying back well ahead of the dryline, given the time of day and the fact that the storms to our north and east were quickly becoming a multicell cluster.

However, it only showed signs of weak rotation at midlevels, per the SRV at 2.4 degree tilt from the KDYX radar at the same time.

Just north of Jacksboro, TX, we positioned ourselves so that we could see the updraft tower of the storm off to our west. There appeared to be a lowering off in the distance, but there was no visible rotation.

Buckey ended up amusing himself with the cows. They were attracted to him for some reason.

We got around to the south side of the storm in Jacksboro and came upon some major chaser convergence. People were on the side of the street road and cars with "SKYWARN" stickers passed while honking. I hope this isn't a preview of what is to come when the tornado season REALLY kicks in.

We decided to head northwest to Wichita Falls to see if anything else would fire along the dryline, but the air was beginning to stabilize, and no Cu field was present. Either way, that was our best way to return to Norman, so we headed north on route 281. On our way out, the back side of the storm we were just watching had a nice line of towering Cu, which made for a great panorama.

Close to sunset, once we had crossed back into Oklahoma on our way to Lawton, we drove under this spectacular shelf cloud that was the remains of a squall line that had fired earlier in the afternoon and was dissipating. Behind this shelf cloud to our northeast was a growing Cb.

It had a better and better radar representation (KFDR base reflectivity 8:02 pm CDT), so we took a detour to the east out of Lawton to see if we could catch a glimpse of the storm. However, it weakened as quickly as it intensified. It was no big deal though, because our detour had also gotten us away from a potential developing hail core in another cell that was just moving over Lawton.

Although today was not a bust in the sense of seeing interesting atmospheric phenomena, it would have been nice to see a more favorable environment with more backed surface winds.