E-Journal of Severe Storms Meteorology

E-Journal of Severe Storms Meteorology, Vol 8, No 3 (2013)

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A Study of Synoptic-Scale Tornado Regimes

Jonathan Garner

Abstract


The significant tornado parameter (STP) has been used by severe-thunderstorm forecasters since 2003 to identify environments favoring development of strong to violent tornadoes.  The STP and its individual components of mixed-layer (ML) CAPE, 0-6-km bulk wind difference (BWD), 0-1-km storm-relative helicity (SRH), and ML lifted condensation level (LCL) have been calculated here using archived surface objective analysis data, and then examined during the period 2003-2010 over the central and eastern United States.  These components then were compared and contrasted in order to distinguish between environmental characteristics analyzed for three different synoptic-cyclone regimes that produced significantly tornadic supercells: cold fronts, warm fronts, and drylines.  Results show that MLCAPE contributes strongly to the dryline significant-tornado environment, while it was less pronounced in cold-frontal significant-tornado regimes.  The 0-6-km BWD was found to contribute equally to all three significant tornado regimes, while 0-1-km SRH more strongly contributed to the cold-frontal significant-tornado environment than for the warm-frontal and dryline regimes.


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