Funky Weather: Squalls, Virga, and Microbursts
Virga — Whenever any form of precipitation (rain, sleet, snow, hail) forms, but then evaporates before reaching the earth, it is called virga. Virga is a common characteristic of microbursts.
Microbursts — A microburst is the complete opposite of a tornado. A tornado consists of convergent upward funnelling winds, while a microburst consists of divergent downward-motion winds. While the wind direction and flow is the complete opposite of a tornado, from afar, the two look quite similar. Microbursts is a type of downburst, but more localized than large-coverage wind shear.
Squall — A squall is simply a drastic, abrupt increase in wind velocity in the midst of a storm; it’s a non-sustained surge in wind speed. They primarily occur away from strong mid-level height falls or mid-level tropospheric cooling because those regions frequently have strong upward wind motions, minimizing the potential for a squalls abrupt downward wind burst.
White Squall — Combine a microburst with squall phenomenon, while at sea, and you get a white squall. A white squall is a violent windstorm that emerges out of nowhere, providing no “black cloud” warning. The white-capped waves and broken water, are the key characteristics of a white squall. They’re mainly considered to be myth, but many sea tragedies have been attributed to these intense nautical microbursts.
2007/10/17 at 11:51 AM
