Images and text
© copyright Gene Moore
On this day we intercepted an LP supercell that was following along the outflow boundary of a strong triple point storm. This occurred southeast of Dodge City, Kansas on a rather warm and mostly clear spring afternoon. Our storm was a small supercell with many of the classic visual supercell characteristics, such as a concentric appearance, updraft separated from the precipitation area and a long inflow band intersecting a turbulent wall cloud. A guaranteed tornado I thought, but what surprised me was it only produced one tornado; the storm it followed produced over a dozen, about half of which occurred in the daylight. In retrospect getting this fine tornado turned out to be a screwup, but the season is still young so there will be time for more tornadoes, or more screwups.
So far this season we have been plagued by a smoking transmission, a DeLorme mapping error that showed a through road, which actually ended up as a locked gate, a sick chase partner and finally on the Happy, Texas day, a dead fuel pump south of Lubbock, TX; which if you haven't guessed was cause for us to call a tow truck. So, here I am on May 7th putting up my first tornado shots and hoping for more opportunities during this active season.
The first shots depict the slowly dissipating wall cloud as the funnel becomes better defined. Note the rain streamer behind the funnel. This is a rather common sight and it's usually seen as the south end of the hook echo on radar. We are looking west-southwest at this time. This funnel was actually a tornado for its complete life, even in the early stages; although, not seen here the video shows a continuous debris cloud that lasted about 7-8 minutes.
These images show a well formed funnel with an increasing debris cloud under the funnel. Of special interest are the small dots strung out across the image just under the funnel. Look at the enlarged shot of the area just under the funnel. This is a flock of birds that got caught up in the circulation and are about to get the ride of their lives. The subsequent images after this time did not show the birds. For the bird lovers in the group, I doubt all were killed by this incident because the tornado was only picking up dirt at this time. So they were probably expelled out the top of the funnel.
Another wider shot of the funnel as it got ready to shoot a condensation needle to the ground.
A narrow needle of condensation took about 30 seconds to reach the ground and expand into a well defined condensation vortex. During this time the debris cloud under the funnel increased its rotational speed. The funnel remains tilted in this image but a surge (microburst) in the RFD (rear flank downdraft) corrected the funnel to a vertical orientation right after this shot.
After the RFD microburst the funnel gives us the more classic tornado appearance. Bright sunshine beaming through the thin rain curtain behind the funnel lights up the cloud. There is a good chance this tornado was over wet ground as the wall cloud was directly behind the rain core on radar. So, I'll bet most of the debris we are seeing is mud not dust.
During the last half of the tornado the lighting changed drastically
from a cool blue to a bright orange, playing havoc with the camera settings at
our location. As dry air descended from the RFD it eroded the wall cloud
completely and let in brighter light. There was a "waterfall" feature on the
back of the tornado; that's where the RFD is so strong that cloud material
pours down the back of the cloud and funnel as it dissipates. Remember, as air
descends it warms, thus evaporating the condensation.
Here is a shot of the Dodge City Radar a little after the tornado dissipated. Our storm is the second cell or the one on the left (west). During this time a second wall cloud formed with strong rotation located up against the east-west rain wall, but it didn't produce a tornado. Looking at the radar image my suspicions were verified. Note the arc (series of dots) coming out of the first cell and curving back to the hook of the second cell. Our storm, unfortunately moved east "behind" this arc or outflow boundary (OFB), thus in the cooler less unstable air. Had it moved along the southern edge of this OFB it would have remained in the explosively unstable environment that formed the first tornado and powered the eastern cell.
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