Grant’s Storm chase last Thursday

By Grant Dade - bio | email

Well, it has taken me awhile but I am finally writing my chase account from last Thursday, May 20th. The severe weather set up from Thursday event included an outflow boundary interacting with a stationary front across Central Texas just south of Dallas.  Early in the afternoon, strong to severe storms developed along and north of a southward moving outflow boundary from Wednesday's convection farther north.  These storms became severe and produced wind damage in the Dikes community of Hopkins County, just east of Sulphur Springs.

It was along the intersection of the southwestward moving outflow boundary and stationary front where supercells would continue to develop throughout the afternoon and move off to the south and east. There were two official tornado reports and numerous reports of large hail, up to baseball size.

The first storm we encountered was in Henderson County near the Cedar Creek Reservoir.  This storm was showing signs of weak rotation but no true wall cloud feature was seen while we were on the shores of Cedar Creek Reservoir.  As we drove south from Tool along 247, we noticed an elephant trunk shaped funnel extending towards the ground.  From our vantage point we could not tell if this funnel reached the ground or not.  By the time I could snap a shot of the funnel, it was much farther off the surface and more horizontal.  This storm continued to produce these funnels that would not quite reach the ground.  It looked as though as these funnels lowered, the cooler air from behind the outflow boundary was undercutting the updraft causing them to rope out before even reaching the ground.  This storm produced at least three funnels before moving away from our vantage point.

From this storm we raced west to catch the latest storm that had developed along the intersecting boundaries.  This storm was showing signs of strong rotation both on radar and from our ground view.  Although this storm would not go on to produce a tornado, large hail did occur.  We were hit with quarter size hail wrapping along the back side of this storm.

Our third storm became the storm of the day for us developing near Waxahachie and moved southeast through Navarro and Freestone Counties.  This storm would go on to produce wind damage and hail up to the size of Baseballs near Corsicana.  From our vantage point it also appears that a brief but rather wide tornado could have touched down over Richland Chambers Lake.

As we approached this storm radar showed a very well developed deep convective supercell, a constant midlevel rotation was show on this storm for well over an hour.  As this storm moved over, we raced south to stay out of the hail core.  For a time we were under a large rotating wall cloud.  It was during this time that I witnessed an event I have never seen before.  We noticed mini vortices about 5 feet in diameter rotating around the wall cloud.  Three or four of these little vortices moved in front of our vehicle.  The did not appear to be in contact with the storms updraft but it was interesting that these dust devil size vortices were moving in the direction of the parent circulation.  Were these mini vortices a precursor to a developing tornado?   I am not sure but it was an event I had never witnessed before.

We finally moved out ahead of the wall cloud and drove down I-45 to Streetman.  It was here we noticed a circulation that appeared to be in contact with the cloud base, a brown swirl rotating around a large bell funnel.  I quickly grabbed my camera and took a photo.  The contrast on the storm was very poor so it was hard to exactly see what we were seeing.  By taking the photo and zooming in a bit and adjusting the contrast, you can see a funnel with what appears to be debris rotating around.  Here the debris, which at first was brown is now white.  It is at this time when the funnel moved over Richland Chambers Lake and the white debris appears to be water.   The next image is a radar grab from the storm two minutes before a snapped the shot of the funnel.  There was strong rotation but not a tight as what you would like to see for a strong tornado.  This could be why there was very little damage on land before this feature moved over the lake.  We drove looking for a damage path but could only find sporadic snapped trees along with one weak structure with its roof blown off.  Was this a large EF-0 tornado?  We will probably never know.  Officially this will go down as a severe thunderstorm with baseball size hail and sporadic wind damage.  But form our vantage point; it looks as though a tornado could have occurred as well.  Next time I will roll video instead of taking a snap shot.  Then everyone could see the rotating funnel and debris wrapping around that we saw.

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