Monday, February 22, 2010

1st Storm Chase of 2010

The first storm chase of the 2010 season ended up providing a little excitement even though our target area was off. Saturday 12Z model runs were pointing to two areas of possible severe thunderstorm development. One was over Louisiana where low clouds and fog would make storm visibility horrible, and the second area was over Central Texas as a dryline was progged to move from Dallas to Waco during peak afternoon heating. We decided to choose the second target based on visibility and an anticipated pooling of moisture out ahead of the dryline. So we decided to head to Corsicana giving us a good north south east and west option depending on where storms developed. Once there a quick look at the new SPC mesoanalysis page, which is amazing, showed instability building in the Fairfield are so we headed south to wait for storm initiation. Once there I found an abandoned house with some very spooky trees and I had to take a shot. You see that at the top of the page. We waited for about 30 minutes and noticed the dewpoint beginning to drop, dry line was mixing through the area. So I took a glance at the NWS in Fort Worth’s Convective Parameters page, which usually performs very well, and noticed the convective interest near Dallas was in the upper 80s, meaning storms were likely to initiate there within the hour. So we raced north.

As we were driving north we noticed storms firing in the Metroplex. The southern storm riding the boundary took on a mini supercellular form. Radar showed 67.5 dbz that never reached higher than 20,000’, as you can see from the volumetric scan.

The next image is the velocity data. The rotation on radar was fairly week but from our vantage point, you could see the updraft tower rotation fairly well.

The reflectivity image shows a small hook on the southwest side of the storm which persisted for about 30 minutes on radar. The view we had of the storm as we approached western Kaufman County was incredible. We were able to see a flanking line, a well defined wall cloud, a tilted updraft, and what appears to be a tornado. In the photo I have it labeled as a tornado look alike but after seeing fellow storm chaser Simon Brewer blog, you can easily see this was a funnel and it was not on the ground. He was much closer to the updraft than I was when my photo was taken.

The storms updraft was quickly undercut by cooler drier air as it moved closer to us. A new updraft began to form on the southeast side of the storm. The photo below is of that rotation updraft with a small funnel trying to develop. Smile Paul!

This updraft was undercut as well and lead to the demise of a very nice mini supercell and left a rainbow coming out of the back of the storm.

New storms were trying to form to our east near Canton but even these storms didn’t have much of a chance as the dry boundary raced east and undercut the storms' development. All in all, not a bad 1st chase day especially for as low of a severe risk we had in Central Texas.

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