19 July 2006 Derecho: A Meteorological Perspective and Lessons Learned from this Event. Ron W. Przybylinski, James E. Sieveking, Benjamin D. Sipprell NOAA / National Weather Service St. Louis Jared L. Guyer NOAA/NWS/NCEP Storm Prediction Center. 2009 Spring Media Workshop.
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Ron W. Przybylinski, James E. Sieveking, Benjamin D. Sipprell NOAA / National Weather Service St. LouisJared L. GuyerNOAA/NWS/NCEP Storm Prediction Center
2009 Spring Media Workshop
250 mb analysis
500 mb analysis
850 mb analysis
RUC 700-500 mb lapse rate (°C km-1)
Composite base reflectivity 1210 UTC
SPC radar animation
Composite base reflectivity 1610 UTC
SPC radar animation
Winchester, IL (WNC) Profiler 1700 - 2200 UTC
SPC Mesoscale analysis for MLCAPE and 0-6 km bulk shear at 2300 UTC
MLCAPE ranged from 2000 – 6000 J kg-1 acrosseastern Missouri throughwest-central Illinois
Deep layer shear weak
with magnitudes of
10 – 22 m s-1
The 19 July 2006 Damaging Wind Convective system followed theParallel Stratiform (PS) archetype
WSR-88D Radar Imageryfrom Lincoln Illinois (KILX)at 2138 UTC
Parallel Stratiform Parker and Johnson 2000
2332 UTC Radar imagery from St. Louis (KLSX). The strongest winds were associated with convective segment #3 (larger echo mass).Several witnessesover southern Macoupin County experience hail up to nickel size with the stronger downbursts behind the leading gust front.
7:01 PM CDT Reflectivity (left), Base velocity (right). The strongest winds were detected with the higher reflectivity cores over northwest Madison County Illinois.
Loop of the evolution of a single severe cell over the western part of the storm complex.
Bunker Hill western part
ASOS / AWOS Surface Observation sites around the GreaterSt. Louis metro area.
When was the last time we documented a case similar western part to the July 19, 2006 Derecho?
Aug 10, 1992. The convective complex formed just southwest of KLSXand moved south-southward through west-central Arkansas. Widespread wind damage occurred with this derecho.
The July 19 2006 damage map reveals that much of the downbursts was oriented from north-northeast to south-southwest – an unusual direction.This direction of damaging winds future intensified the degree of damage over the greater St. Louis metro area.
Tower Grove Park downbursts