Robert Hall and I left Denton, Texas
at 12:40 PM targeting Watonga, OK, northwest of Oklahoma City. Aware of the strong
cap on the OUN and FWD soundings, we hoped for a dryline surge and locally backed winds to
lend convergence despite model indications of persistent southerly flow parallel to the
boundary. Initial cloud deck was scattered in Southern Oklahoma and bases were
appealingly low. Vertical development of early congestus also looked promising as
midlevel instability was shaping up nicely. Steve Miller called with details of an
MCD from the Storm Prediction Center before we turned north at Chickasha and set up near
El Reno.
Around 5:00 PM a line of small cu developed out west but evaporated quickly, repeating
the cycle several times until it was clear the cap was too strong.
When the midlevel cloud shield passed overhead we saw a remarkable three-tiered
structure of rich reds and pinks facing the setting sun. These looked something like
striations to storm-starved chasers like us, and mammatus-like protrusions hung from the
underside of the deck. The entire visible section of the shield was circular, giving
the appearance, with all visual features combined, of some strange cross between an
anvil and an orphaned but still rotating updraft.
At 7:00 PM we drove back to Denton and arrived in time to film the frontal passage from
downtown. |
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