Session 6.1 Observations and quantification of low-level mesovortex evolution within the 4 July 2004 southwest Missouri high wind event

Tuesday, 7 November 2006: 1:30 PM
St. Louis AB (Adam's Mark Hotel)
Angela Lese, NOAA/NWSFO, Louisville, KY

Presentation PDF (747.6 kB)

A convectively-driven high wind event propagated from central Kansas to northern Alabama on 4 July 2004. A detailed observational analysis has been performed on the portion of this quasi-linear convective system (QLCS) which propagated through the county warning area of the National Weather Service (NWS) office in Springfield, MO (KSGF). Four mesovortices were observed, mainly at low levels, along the leading edge of the QLCS. Only two are examined here as the northern-most mesovortex was quickly amalgamated by the cyclonic line-end vortex, and the southern-most mesovortex was too distant to be properly sampled.

In this case study, damage surveys revealed that one mesovortex produced intense straight-line winds and a tornado, while the other produced minor wind damage. Using WSR-88D Doppler radar data from KSGF, the main objective is to quantify these two dominant mesovortices to identify characteristics that may be relatable to damaging surface winds or tornadoes. The mesovortices have been contrasted and the results will be revealed. Additionally, possible effects that an intersecting outflow boundary may have had on low-level evolution of the tornadic mesovortex will be discussed, as well as implications to operational NWS warning techniques.

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