Vol 7-5 2012

Environments of Significant Tornadoes Occurring within the Warm Sector versus Those Occurring along Surface Baroclinic Boundaries

Jonathan Garner

Abstract

Archived, hourly-analysis proximity soundings from the operational Rapid Update Cycle (RUC) model are used to examine the vertical wind profiles and thermodynamic parameter space associated with significant tornadoes (rated F2+/EF2+) occurring in the warm sector (33 events) of synoptic cyclones, as well as those occurring along surface baroclinic boundaries (52 events), during the period 1999-2010 over the central and eastern United States.  These tornadoes were associated with either the warm sector or a surface baroclinic boundary through the use of subjective surface analyses, supplemented by visible satellite and WSR-88D imagery.  A key finding is that measures of ground-relative wind speed, storm-relative helicity, and bulk wind difference are much stronger for warm-sector significant tornado events.  In contrast, thermodynamic parameters did not distinguish between the two regimes.  Among all of the parameters examined, the observed and predicted speed of the parent supercell showed the most substantial differences between warm-sector and boundary significant tornado environments.

Full Text: PDF

Citation:
Garner, J. M., 2012: Environments of significant tornadoes occurring within the warm sector versus those occurring along surface baroclinic boundaries. Electronic J. Severe Storms Meteor., 7 (5), 1-28.

Keywords:
storm environments, tornadoes, supercells, fronts, mesoscale processes, operational forecasting