With all the heat and humidity around recently and given that thunderstorms feed on such reservoirs, one may wonder why the storms on Tuesday weren't very severe. Besides the lack of any defined surface front to help focus thunderstorm development, another limiting factor was weak winds aloft. The featured chart depicts July sounding level percentiles of wind speed for Omaha based on the morning sounding on Tuesday. Winds aloft were generally very light and even below the 5th percentile at 250 and 200 mb. Severe Thunderstorms generally need stronger winds aloft to help segregate an updraft and downdraft within the storm. With weak winds, storms tend to pulse with the downdraft disrupting the updraft.

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Tags:   sounding