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

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.