27 Environmental Evolution and Storm-Scale Observations of the 31 March 2016 Northern Alabama Tornado Event during VORTEX-SE

Monday, 7 November 2016
Broadway Rooms (Hilton Portland )
Anthony W. Lyza, Univ. of Alabama, Huntsville, AL; and T. A. Murphy, D. M. Conrad, and K. R. Knupp

An EF2 tornado impacted areas around Hartselle and Priceville, Alabama, during the late evening hours of 31 March 2016, during the 3rd intensive operations period (IOP) of year 1 of the Verification of the Origins of Rotation in Tornadoes Experiment - Southeast (VORTEX-SE) field campaign.  The supercell responsible for the Hartselle-Priceville tornado was one of numerous supercells to impact the VORTEX-SE domain during IOP 3, but the only one to produce a confirmed tornado.  Many of the other supercells observed during the event exhibited intense mesocyclones and well-defined hook echoes but were unable to produce tornadoes.  As part of the VORTEX-SE field campaign, numerous mobile sounding teams, two mobile scanning Doppler radars, the fixed-site Advanced Radar for Meteorological and Operational Research (ARMOR), multiple mobile profilers, and mobile disdrometers were deployed across north-central and northwestern Alabama to sample the evolution of the convective environment and storm-scale processes associated with the supercells during the event.  In this presentation, we overview the environmental and storm-scale characteristics observed during IOP 3 of VORTEX-SE.  These include early-evening low-level destabilization of the observed thermodynamic profiles across north-central Alabama, a marked increase in low-level vertical shear around and after sunset, and a change in storm mode from classic to high-precipitation (HP) supercell hybrids with rather “fat” hook echoes to classic or even low-precipitation (LP) to classic supercell hybrids with small hook echoes and reflectivity cores.  Storm-scale interactions with other mesoscale features, including a wave-like feature that passed through the Hartselle-Priceville tornadic supercell, are also examined.  Operational ramifications for the southeastern severe storm environment and considerations for future observing of severe storms in the southeastern United States are discussed.
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