Analysis of a destructive wind storm on 16 November 2008 in Brisbane, Australia

Richter, Harald and Peter, Justin and Collis, Scott (2014) Analysis of a destructive wind storm on 16 November 2008 in Brisbane, Australia. Monthly Weather Review, 142 (9). pp. 3038-3060. ISSN 0027-0644

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Abstract

During the late afternoon on 16 November 2008 the Brisbane (Queensland, Australia) suburb of “The Gap” experienced extensive wind damage caused by an intense local thunderstorm. The CP2 research radar nearby detected near-surface radial velocities exceeding 43 m s−1 above The Gap while hail size reports did not exceed golf ball size, and no tornadoes were reported. The storm environment was characterized by a layer of very moist near-surface air and strong storm-relative low-level flow, whereas the storm-relative winds aloft were weak. While the thermodynamic storm environment contained a range of downdraft-promoting ingredients such as a ~4-km-high melting level above a ~2-km-deep layer with nearly dry-adiabatic lapse rates mostly collocated with dry ambient air, a ~1-km-deep stable layer near the ground would generally lower expectations of destructive surface winds based on the downburst mechanism. Once observed reflectivities exceed 70 dBZ, downdraft cooling due to hail melting and downdraft acceleration based on hail loading are found to likely become nonnegligible forcing mechanisms. The event featured the close proximity of a hydrostatically and dynamically driven mesohigh at the base of the downdraft to a dynamically driven mesolow associated with a low-level circulation. This proximity was instrumental in the anisotropic horizontal acceleration of the near-ground outflow and the ultimate strength of the Gap storm surface winds. Weak storm-relative midlevel winds are speculated to have allowed the downdraft to descend close to the low-level circulation, which set up this strong horizontal perturbation pressure gradient.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Access to published version in accordance with the copyright policy of the publisher.
Faculty / Department / School: Current - Institute for Agriculture and the Environment
Date Deposited: 11 Apr 2017 01:10
Last Modified: 28 Apr 2017 02:58
Uncontrolled Keywords: buoyancy; cold pools; downbursts; hail; mesocyclones; radars/radar observations
Fields of Research : 04 Earth Sciences > 0401 Atmospheric Sciences > 040199 Atmospheric Sciences not elsewhere classified
04 Earth Sciences > 0401 Atmospheric Sciences > 040102 Atmospheric Dynamics
04 Earth Sciences > 0401 Atmospheric Sciences > 040107 Meteorology
04 Earth Sciences > 0401 Atmospheric Sciences > 040106 Cloud Physics
Socio-Economic Objective: D Environment > 96 Environment > 9602 Atmosphere and Weather > 960202 Atmospheric Processes and Dynamics
E Expanding Knowledge > 97 Expanding Knowledge > 970104 Expanding Knowledge in the Earth Sciences
D Environment > 96 Environment > 9602 Atmosphere and Weather > 960203 Weather
Identification Number or DOI: 10.1175/MWR-D-13-00405.1
URI: http://eprints.usq.edu.au/id/eprint/30997

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