May 23, 2011

May 23: At least ten funnel clouds/possible tornado

Thom taking a picture of what might be a developing tornado near Kingfisher
Thom and I were eating lunch in Fairview OK (about 60 miles northwest of Oklahoma City) watching the first Fairview storm develop.   It was already rotating soon after it had an anvil, complete with an elevated horseshoe base.  Right away, it was odd....on the southeast side of the updraft tower was a very pronounced laminar funnel...not from the rain free base.  There were four other sinuous funnels, elevated bases...but with large extension from the forward flank tower.   We saw yet another funnel cloud with this storm after it backbuilt about an hour later, and a tornado warning appeared a short time after.

Nice looking wall cloud northwest of Kingfisher at around 8:15 PM CDT.
At this time the radar showed a hook echo.
 I'm not sure we were witnessing splits.   It seemed that the process was more like train echoing...  I think the weak700 mb winds were allowing precip to wrap into the updraft area....causing outflow surges back against the shear.  The net effect was that the updraft area appeared to stay near Fairview.

Two midlevel funnels near Fairview
Look closely---a sinuous midlevel funnel

Panorama of one wall cloud, looking east, during one cycle of the storms
I don't know how many times we circled around these storms back west, then east, then back west.  There were some very impressive ground scraping wall clouds that then became forward flank shelf clouds as the outflows crashed through and a new upraft score redeveloped northwest.   Anyway, after many such cycles, the last one we saw near sunset was the best....and it had a real nice hook...with TVS signaatures showing up pretty continually for an hour or so....but though we were sure we saw "near tornadoes" on the wall cloud...the thing always looked outflow dominated with a ragged base.  We were pretty sure we pushed through a spinup  or a large gustnado...though it may have been a weak tornado.

The pictures at right illustrate some of the funnels we saw.   The first picture at top shows the wall cloud associated with the hook echo shown on the radar plot (at bottom right).  We think it may have produced a very brief tornado to the north, and as pointed out above, as we drove south we passed through a weak circulation (resembling an early spinup of a tornado) coming across the ground.  It may also have been a gustnado.

All in all, a nice day of chasing. 

Another midlevel funnel near Kingfisher

Under the flanking line/shelf....very ominous.
Hook Echo/TVS from GRLevel3 for final storm of the day.
This was the first funnel of the day on the southside of the updraft base of the storm developing near Fairview