It was apparent early on Tuesday that we had a pretty good setup for some thunderstorms, should a few things fall into place. And they certainly did.
The morning was dry here with rain off to the west, but analyses from the Storm Prediction Center showed an axis of instability right through the middle of our area, and surface reports indicated very high, almost midsummer-like, dew points in the lower and mid-70s. Aloft, a disturbance was moving in to provide additional lift. You might say the atmosphere was "juiced". In the afternoon, things started to fall into place when the sun came out and temperatures warmed up into the mid-80s. All that provided plenty of fuel for the activity moving toward us from the west.
The result was an intensifying squall line that was not severe at first, but seemed to peak right about the time it reached Columbus and Harris County. A couple of severe thunderstorm warnings were eventually issued for the likelihood of winds exceeding the threshold of 58 miles per hour.
Image from WRBL First Alert radar as squall line advanced - note bow-like configuration of line moving toward Muscogee/Harris, most likely concentration of high winds. Line merged with other storms seen south of Columbus which may have enhanced intensity.
And apparently the severe winds did verify, even though the wind doesn't have to be that strong to knock down branches and even uproot trees. After the initial squall line, a large area of cool rain took the rest of the afternoon and early evening to move through. The result: 3.03" of much-needed rain in my regulation rain gauge (the CSG automated station reported only 1.94", which due to the extremely heavy rainfall rate I am a bit skeptical of its accuracy*) and at least in my yard only a few twigs and pine cones lying about.
Watching the wind from inside it was clear that the winds were unidirectional and showed no sign of rotation. Yet the NWS is expected to visit a few sites where there was a bit more extensive tree damage to see if there might have been a brief tornado touchdown.
I see it as unlikely that yesterday's storm system could have produced a tornado. We rarely see tornadoes here after mid-May or so, yet we do often see squall lines and wind damage like yesterday's well into June before a midsummer thunderstorm pattern normally takes over. The large-scale setup for the type of wind shear needed for tornadoes was not present, demonstrated by the fact that we were never under a watch and also that SPC had essentially a 0% tornado threat for this area. From what I saw, the tree damage has "downburst" written all over it, caused by sudden bursts of straight-line wind. One interesting thing is that I observed two rounds of high winds: the first one part of a gust front just out ahead of the rain, and the second one along with the rain, when a downburst is most likely to occur. I would estimate that wind gusts were close to 50 mph in both rounds, at least in my location.
Still, it's possible to have a quick spin-up tornado happen even without the normal prerequisite atmospheric conditions. These are usually termed "gustnadoes" and happen because of wind interactions on a scale too small to be detected by any radar. They can rip up trees, but are weak and won't do too much damage to your house unless a tree happens to fall on it. If the NWS does come to the conclusion there was any damage caused by a tornado, it would almost certainly fall into that category. (And I would still want to see some verification on how they came to that conclusion.)
So what about today? The air is not nearly as unstable in this area this morning, partly due to the cooling from yesterday's rain which may help put a lid on development. The upper air support doesn't look quite as strong, either. With enough warming this afternoon, though, I expect at least some showers and probably a few storms, just not the kind of squall line was saw on Tuesday.
Thunderstorms are a fact of life down here in the Gulf states, and we'll no doubt see plenty more of these as we move into the summer season, most of them ordinary but capable of knocking over a few trees now and then.
*It's been my experience that the automated gauges now used by the NWS produce totals in extremely heavy rainfall rate situations that are sometimes too low. Many stations use a regulation 4" diameter gauge as a backup, and I'd be interested to see if the totals from yesterday's storm match or not.