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This loop of Twin Lakes Oklahoma WSR-88D base reflectivity shows the movement of supercell convection from 22:04 to 23:56 UTC on 03 May 1999. Note the well-defined hook echo that develops in southcentral OK after about 22:50 UTC.
5-minute surface reports from the Oklahoma Mesonet (cyan) are overlaid on the radar imagery, along with the standard hourly ASOS reports (green). Note the mesonet winds which backed to southeasterly across southern and central OK, helping to enhance favorable storm-relative flow.