912 Meteorological and Hydrological Factors Leading to Widespread Flooding in Northern Louisiana During March 2016

Tuesday, 24 January 2017
Washington State Convention Center
Matt Hemingway, NWS, Shreveport, LA; and F. Bowser

Excessive rainfall during the second week of March led to widespread flash flooding and subsequent hydrologic flooding across parts of the Ark-La-Tex region, prompting flash flood emergencies in what eventually became a long duration historic flood event. A strong cutoff low over northern Mexico carved out a deep trough that prevailed for the better part of a week. The resulting deep southwest flow aloft led to a surge in rich, tropical moisture from the eastern Pacific across much of eastern Texas and all of northern Louisiana. Surface conditions only further enhanced what was already a favorable synoptic setup for excessive rainfall as a stalled out frontal boundary lingered over the region for several days, allowing low-level southerly winds to supply additional moisture from the Gulf of Mexico. Several rounds of very heavy rainfall produced total event rainfall amounts of at least a foot in many locations with extreme totals of over 20 inches in portions of northeast Louisiana. The end result was extreme flooding which closed sections of interstate highways for days, led to area-wide school closures, and broke all-time record levels on many area waterways.
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