May 8, 1993 - Lake Arrowhead/Scotland, Texas Tornado

Al Moller and I teamed up on this day. We had chased another tornadic storm northeast of Wichita Falls, Texas before chasing the "Lake Arrowhead" storm.

Chasers often name storms for locations where they inflict damage. This storm damaged a number of homes near Lake Arrowhead. (Note: I had misidentified the location of the tornado damage in an earlier revision of this report. Lake Kickapoo, which is about 30 miles west of Lake Arrowhead, was erroneously listed previously as the site of the tornado damage. Conversations with Al Moller and re-review of my original chase log confirmed the need for this correction. Correction made 1/22/2000.)

The storm we had been pursuing previously had moved northeast across the Red River. We had to give up the chase because the road we were on dead ended at the Red River. Gene Rhoden had taken a different route and intercepted the storm in Oklahoma where he observed and photographed a tornado a few miles north of the Red River.

We drove south on highway 148 through Henrietta, then west on highway 174 to a spot just east of Windthorst, to intercept the next storm in a broken line of storms, all of which were located ahead of a dry line. The storm we chose was moving to the northeast toward us. The National Weather Service issued a severe thunderstorm warning for the storm as we intercepted it.

I've expanded the number of photographs included with this event because of the interesting storm evolution that is shown. Note that the wall cloud/mesocyclone appears to have formed on a gust front.

	We approached the storm from the east. This image shows the rain free base with the south end of the anvil overhead. The storm was still getting organized as evidenced by the scalloped anvil edge. Storms that produce straight edged anvils are thought to possess a more constant updraft associated with a supercell updraft. (While supercell updrafts vary with time, they typically produce a fairly thick straight edged anvil as compared to the uneven and often thin anvil edge produced by a multicell complex. Supercells also typically produce a more diffluent anvil than weaker storms, due to the higher updraft rates produced.)
	Looking west northwest at the developing wall cloud.

	Looking WNW at a wall cloud as the storm changes from classic to an HP configuration. Note the heavy precipitation and the tail cloud extending to the left (southwest) of the wall cloud.
	The wall cloud lowered as the storm passed near Scotland, north of Windthorst, Texas (south of Wichita Falls).



	Looking north - the tornado touched down as precipitation wrapped around the mesocyclone, eventually obscuring the tornado.
	I reported the tornado to the National Weather Service Office in Wichita Falls via the Wichita Falls SKYWARN net. However, we had difficulty reaching the repeater due the distance involved and because the repeater required a sub-audible tone for access. The sub-audible tone had been only recently installed and we didn't know the tone frequency required. Eventually, we found the correct tone, but still couldn't hold the repeater. A local ham relayed our report by listening on the repeater input frequency.
	Looking northwest as the storm approached the small community of Blue Grove, Texas. The updraft area and the tornado were shielded from view by heavy precipitation. We drove north to get a look at the mesocyclone, which was located north-northeast of the precipitation core. The tornado funnel had dissipated, but frothy condensation was forming on the ground and being sucked up into a wall cloud that was only a few hundred feet off of the ground. Unfortunately, neither Al nor I got a photograph. The storm had accelerated and the green precipitation core was fast approaching our location. To escape a certain pummeling by large hail, we turned east and raced down a narrow one lane dirt "road" for 10 to 12 miles to highway 287, barely escaping the jaws of this intense HP supercell.
	Looking north-northwest from highway 287 east of Blue Grove. We stopped briefly to look back at the HP monster that had been chasing us across the North Texas prairie. This is what we saw. A dark foreboding precipitation core with a distinct greenish tint. Note the inflow band feeding into the primary updraft northeast of the precip core.
	The mesocyclone that had produced the earlier tornado was located on the northeast or north side of the precipitation core when this image was made. It reportedly produced another tornado northeast of Bowie, Texas in Montague County after this photograph was taken. A new lowering (pictured here) and mesocyclone started taking shape southeast of the rain core along the southern flank. Occasionally, new mesocyclones form southeast of the precipitation core, then migrate around the eastern side to mature on the northeast side, in the HP configuration. This type of storm evolution is not common, but it is not extremely rare either.
	Funnel shaped lowerings formed as the new mesocyclone strengthened. This image was digitally processed to significantly lighten it. At the time this image was made, light levels were low and it was difficult to discern any details of the lowering. The image has not been otherwise altered.
	Tornado? Wall cloud extending to the ground? It was too dark to detect exactly what was going on under this lowering. What follows is an interesting sequence showing the development of the new wall cloud.






	In this highly processed image, Al Moller (lower right corner of image) photographed the storm as the core again charged toward our filming location. The precipitation core had an eerie glow that was due to evening light being "conducted" down the intense rain shaft.