Chase Log: April 05th, 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.
Total Distance: 450 miles
Target Area: East of an Ardmore, OK, to Gainesville, TX line
Chase Area: Madill, OK, to Durant, OK, to Paris, TX, to Greenv
Maximum SPC Risk category: Moderate
Watches:
Tornado Watch 125
Mesoscale Discussions (MCDs): 489 and 493
Another day with modified continental air advecting into the southern plains ahead of a strong upper-level cut-off low and deep (though filling) surface cyclone. I was hoping to get mid-60 dewpoints into southeastern OK and northeastern Texas, where shear profiles and instability (2000-2500 j/kg SBCAPE) were forecast to be sufficient for tornadic supercells. The previous low, however, wiped the Gulf clean, which was the reason the area was only able to advect modified continental air. At any rate, my preliminary target was an area east of the line from Ardmore to Gainesville. We left around 11:30am, after reviewing the latest RUC guidance (which, added to our optimism for tornado potential in our target area).
After getting a phone call from Dan Dawson, who told us that he thought it best (based on SPC mesoanalysis and the latest model runs) to stay just north of the Red River, we headed east out of Ardmore towards Durant. I was expecting storms to initiate between 3pm and 5pm, so I was quite surprised to see towers going up before 3pm on our way towards Madill, right as the SPC Tornado Watch was coming across the weather radio. We stopped to take some pictures and watch the situation develop, which also gave me a good time to check radar and mesoanalaysis data. Hmm... Radar was showing that storms were already linear in nature, with a nearly solid line of convection from southcentral OK to northeastern OK. Well, there was a break in the convection towards the south (where the stronger cap resided), so we kept out eyes to the convection firing immediately along the Red River. Storm motion was relatively slow, so things were easy to keep track of.
We continued east towards Durant to see if we could find some data access, since my cell phone data option ceased working. While in Durant, we lost sight of updraft bases, so I was starting to get more and more pessimistic about the situation. We eventually gave up on data and headed south towards Denison, driving through some very heavy rain and small hail on the way. Storms seemed to be less linear farther south, and, with the tail-end Charlie not far away, we headed east towards Bonham to position ourselves ahead of the convection and get a good view of the situation. Again, more heavy rain and small hail, and the storms were very linear in appearance. Ugh. Products coming out of the Fort Worth, TX, NWSFO continued to highlight a supercell tornado risk, though it was quite evident that this was not going to happen. To make matters worse, on our way south of Honey Grove towards Ladonia and Commerce, I saw that there were several tornado warnings for the storms in eastern Oklahoma. It seemed that the line of convection was able to split up a bit into more discrete supercells. Great... At least there weren't any confirmed tornadoes (yet) for this activity.
We continued to head south then southwest to find the "tail-end Charlie", which seemed to mvoe farther and farther south as storms developed southward along the south end of the squall line. We eventually called it a day with an hour of sunlight left as we approached Greenville.
All in all, it was quite a bust. The first significant instability of the season was able to developed in the target area, though I can't imagine that this instability (2000-3000 j/kg SBCAPE) was realized by these storms, since the updrafts, for the most part, looked very soft. In fact, the updrafts on March 21st (with 1000 CAPE) looked more vigorous than these updrafts (with more than twice the CAPE available). Surely the fact that these storms were not supercells (and thus did not have a mesocyclone, which would otherwise have enhanced the updraft significantly) played the biggest role in their apparent lack of strength. We did drive through some small hail, though nothing was too impressive. I mean, no nice structure, no real severe weather... Ugh.
I suppose I have to expect to bust every now and then, but it was quite frustrating to bring a friend out (Erin, who had always wanted to go on a chase) on a chase which was a bustola. Oh well, can't expect much from modified continental air courtesy of the pattern that's been present for the past 3-4 weeks. Bring on some real Gulf moisture; bring on May.
No pictures worth posting here since there wasn't much to take pictures of...
