There's a massive thunderstorm in the area [....]  The weather service even said there was a squall line and "rotation" over San Antonio, which is close by. They put out a tornado warning.
Source... radar indicated rotation.
It looked like you got the front of 1 of the eventually transcontinental winter storms that first made news in California. The "rotation"
in that weather alert is on the small scale
of an individual tornado
, and does not affect the movement of the overall winter storm
. Even so, depending on the altitude of the base of the clouds relative to local ground, the radar-detected funnel cloud might not touch down at all
1 thing that seemed odd about the storm, was the rotation counter-clockwise
of the whole storm
, like an ordinary summer tropical storm
, except that it was following an inland more-or-less southeastward path like a winter storm
. When the storm front made news in-&-near San Antonio, it seemed to have no "rear" quadrants
- .  But as it neared the Mississippi River, most observant viewers accustomed to watching the approach of tropical storms on animated radar should've been able to eyeball the current hour's-worth of animation of the regional radar mosaic
- ,  and behind the front, see a "poorly organized" very broad center, conspicuously clear (i.e. nonreflecting) to radar, about which the storm was rotating near the Texas/Louisiana border. Even then the storm was mostly a convex dual-quadrant
- front and not much reflecting where a circular storm would have its rear quadrants
apparently took most of the fight out of the storm; by the time it got to Central Florida
, there was none of the forecast "possible thunderstorms" nor high winds, even though we're still in our bonus winter "tornado season". But the rotation was even more obvious in the half-dozen frames of an hour's-worth of radar animation[**],  which near midnight EST overnight showed a storm extending from the Florida/Georgia border south to the north coast of Cuba, organized into a shape more like a circle, rotating counter-clockwise around the center of the peninsula. It's moved a surprisingly short distance eastward this morning, and it's decayed quite a lot. Readers who act quickly should be able to see a more-or-less circular remnant
, rotating around an inferred center a little north of Lake Okeechobee (the largish light-blue spot 1/3 way from the bottom of the peninsula).
So my assumption that transcontinental winter storms
behaved like simple
of wind & cold coming out of the Eastern North Pacific (thus making landfall along the U.S. Northwest coast) has now been ruined. What meteorological model for winter storms deserves to replace it?
Note +: E.g., the absence of funnel-cloud touch-downs is how Central Florida avoided potential tornado disasters 1 night a month ago (i.e., Jan. 22, 2017).
Note *: (U.S.) NWS "Southern Mississippi Valley Sector": #60;https://radar.weather.gov/ridge/Conus/southmissvly_lite_loop.php
>. I suppose these are short-interval animated GIF
Note **: "Southeast Sector": <https://radar.weather.gov/ridge/Conus/southeast_lite_loop.php
Note #: Tropical-storm quadrant
diagram (storm movement depicted is almost the reverse of this topic's subject storm, so if helpful for visualization, rotate it 180°--225° in the direction shown by the green arrows: <http://www.hurricanescience.org/images/hss/RightSideStorm_labeled.jpg