14.6 Manifestation of Obstacle-like Effect of Severe Thunderstorms in Satellite Storm Images

Friday, 19 August 2016: 9:45 AM
Madison Ballroom CD (Monona Terrace Community and Convention Center)
Pao K. Wang, Univ. of Wisconsin, Madison, WI; and K. Y. Cheng

Deep convective storms develop strong updrafts which sometimes behave like obstacles to the ambient flow. The possibility of this phenomenon has been proposed previously but questions about it linger. Recently we have seen evidence of this obstacle-like effect in the satellite images of some severe thunderstorms and this paper reports on our findings. The manifestations of this effect in satellite storm images include above-anvil cirrus plumes, jumping cirrus, cold-V (enhanced-V) and associated signatures, and storm top ship waves. These features appear in both visible and infrared images. In this paper, we will show example images that illustrate the features that we believe are manifestations of the obstacle-like effect. Then we will use a physics-based cloud resolving model to simulate some typical severe thunderstorms to show that the model can reproduce the above-mentioned features. We will then use the model physics to explain the physical mechanisms responsible for the generation of such features. We will show that there are regions in the updraft core of the storm that behave as quasi-obstacles that block the ambient flow to produce the observed features. Understanding of the physics of these features is not only important for the fundamental science of storm but also useful for the nowcast of severe storms.
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