SPECTRUM OF MCS EVOLUTION

(Bowing Convective Windstorms)

 


Since 1994, the COMET Cooperative Project between WFO St. Louis and Saint Louis University
has allowed us to investigate the spectrum of storm evolutions associated with bow echoes and 
squall lines which produced damaging straight-line winds, and non-supercell tornadoes across the 
Mid-Mississippi Valley Region.  In many of our cases, wind damage stretched over 150 to 200
miles in length.  Over one third of our cases occurred during the late night or early morning hours 
while the remaining MCS events formed either during mid day or the late afternoon.  In many of our 
cases, the presence of an external  boundary caused by earlier convection or a quasi-stationary
frontal boundary was documented.  Such boundaries played a role in either intensifying a pre-
existing vortex or caused a vortex to rapidly form and intensify.  We will further expand upon this 
issue with the cases shown below.

The information presented is a sample of the MCS bowing events we studied over the past several
years.  Each case will begin with a brief overview of the storm's pre-convective environment.  This 
part will be followed by specific segments of the storm's evolution.  In many cases, we will present 
interesting aspects of the storm reflectivity and Doppler velocity structures, and vortex evolutions 
which may form along the leading edge or northern side of the bowing segment.  Rotational velocity 
(Vr) and Mid-Altitude Radial Convergence (MARC) time-height traces will be shown to view the 
evolution of tornado(non-tornadic) vortices and the MARC velocity signature.  Some of the cases 
presented here might be good candidates for instructional use.  If you have questions about the 
content in each case, please feel free to contact Gary Schmocker or Ron Przybylinski.

Thanks

 


Severe Case #1: 25 May 1996
      Preconvective Environment
      Radar Analysis


Severe Case #2: 14 June 1998
  
  Preconvective Environment
       Radar Analysis

Severe Case #3: 18 June 1998


More cases will be forth-coming.

 

Back to COMET - Damaging Wind Studies

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