Skip Talbot
EF5
I wasn't paying much attention today's setup, and was surprised when I saw screen captures of a large cone tornado that David Drummond was streaming:
Very impressive considering that the report was just outside of SPC's 2% tornado line. More intrigued about what was going on down there, I started to look at some of the surface observations. Metars in the region were showing dews in the lower 40's and temps in the 80's. Now I'm baffled. That's a huge T/Td spread for a large, fully condensed cone tornado like that. I had to dig a little deeper to see what was really going on.
The afternoon HRRR did a really nice job with the setup a few hours before the event occurred. There's a pinpoint spot with a moisture convergence bullseye near Silverton, TX. The forecast dews there are in the mid 50's, not bad at all for that elevation. The HRRR also showed the east/west line of cells of firing along the boundary draped across the panhandle. A forecast sounding in the warm sector shows some really nasty temp/dewpoint spreads and sky high LCL's. In the wake of the initial storms, however, there is considerable cooling and moistening of these profiles, and that's exactly where the producing tracked: right on top of this convergence bullseye, and in the wake of the leading supercells where the pump had been primed. It seems there was just enough instability, huge curving hodographs, and perhaps some outflow boundaries at work, and a fat cone was the result. It pays to pay attention to the finer details when there is weather in your backyard!
![540761_4664249046430_2076423912_n.jpg](/proxy.php?image=https%3A%2F%2Fsphotos-b.xx.fbcdn.net%2Fhphotos-prn1%2F540761_4664249046430_2076423912_n.jpg&hash=e63dc923c0393ba0fa951e24da1602f3)
Very impressive considering that the report was just outside of SPC's 2% tornado line. More intrigued about what was going on down there, I started to look at some of the surface observations. Metars in the region were showing dews in the lower 40's and temps in the 80's. Now I'm baffled. That's a huge T/Td spread for a large, fully condensed cone tornado like that. I had to dig a little deeper to see what was really going on.
![549509_10100520498004841_1389305623_n.jpg](/proxy.php?image=https%3A%2F%2Fsphotos-a.xx.fbcdn.net%2Fhphotos-prn1%2F549509_10100520498004841_1389305623_n.jpg&hash=ee6480f16bbba99cc949517e00f54f48)
The afternoon HRRR did a really nice job with the setup a few hours before the event occurred. There's a pinpoint spot with a moisture convergence bullseye near Silverton, TX. The forecast dews there are in the mid 50's, not bad at all for that elevation. The HRRR also showed the east/west line of cells of firing along the boundary draped across the panhandle. A forecast sounding in the warm sector shows some really nasty temp/dewpoint spreads and sky high LCL's. In the wake of the initial storms, however, there is considerable cooling and moistening of these profiles, and that's exactly where the producing tracked: right on top of this convergence bullseye, and in the wake of the leading supercells where the pump had been primed. It seems there was just enough instability, huge curving hodographs, and perhaps some outflow boundaries at work, and a fat cone was the result. It pays to pay attention to the finer details when there is weather in your backyard!
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