NWS Lubbock

2012 (18th-19th): Two separate rounds of severe thunderstorms struck parts of the South Plains and Rolling Plains this
afternoon and evening ahead of a vigorous upper trough. By mid-afternoon, a dryline ignited widely scattered supercell
storms from near Childress south to near Aspermont. Marginally severe hail was common with these supercells, but one
photogenic supercell south of Guthrie produced a funnel cloud that was observed by multiple storm chasers. As the dryline
retreated early in the evening, a left-moving supercell organized in northwest Garza County and raced north-northeast up
to speeds of 60 mph for the next 2.5 hours accompanied by large hail up to golfball size and severe winds. A second and
more extensive round of storms erupted after sunset over the southwest South Plains as a Pacific cold front collided with
the retreating dryline. The result was an extensive squall line that at one point extended from the Oklahoma Panhandle
south to the western Permian Basin. Strong low-level shear in the vicinity of this squall line resulted in the formation
of at least three persistent, non-tornadic circulations as observed by the Lubbock WSR-88D. One of these circulations was
sampled in high detail by research meteorologists from Texas Tech University near Reese Center using mobile Doppler radars
and high resolution surface stations (sticknets). The mobile data indicated these vorticies were likely gustnadoes
producing very localized wind gusts up to 78 mph. Shortly after midnight, the squall line intensified in the southeast
Texas Panhandle where downburst winds of at least 74 mph caused numerous instances of mostly minor structural damage in
Memphis. The most visible damage was caused after a tin roof was lifted and thrown into a nearby health clinic collapsing
a small exterior wall. Also, portions of the high school football stadium press box were removed. The majority of the
damage reports involved downed tree limbs, power lines and road signs. Some fences were also blown over and roofs were
reported to have sustained generally minor damage. Fortunately, no injuries occurred.