Symposium on VORTEX: What We Have Learned-Where We Must Go

6.4

Some surface observations in hook echoes obtained by a mobile mesonet

Paul Markowski, University of Oklahoma, Norman, OK; and J. Straka and E. Rasmussen

Preliminary analyses are presented of surface data collected by a mobile mesonet within hook echoes and rear-flank downdrafts (RFDs). Cases included both tornadic and non-tornadic supercells. The mobile mesonet data revealed several interesting characteristics of hook echoes and RFDs not appearing in past numerical simulations nor resolved in thermodynamic retrievals. These features included a narrow ring of large pressure excess (>5 mb) in the RFD surrounding the tornado, relatively high buoyancy in some RFDs (often presumed to be strongly negatively buoyant), and lack of baroclinity in the hook echoes of several tornadic supercells. The association between RFDs and hook echoes and tornadoes is well-known; however, the dynamical relationship is poorly understood at best. Thus, these findings may have important implications for tornadogenesis theories.

Session 6, Observations of mesocyclones and tornadogenesis
Thursday, 13 January 2000, 8:00 AM-10:00 AM

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