Posted: Aug 12, 2014 5:45 AM by Meteorologist Josh Eachus
Updated: Aug 12, 2014 12:07 PM
On Monday, a line of showers and thunderstorms passed through the Baton Rouge area with a photogenic phenomenon leading the way.
While the parent trigger for the shower and thunderstorm activity was a cold front, what set up on the leading edge of evening precipitation is known as a gust front.
The National Weather Service defines a gust front as "the leading edge of gusty surface winds from thunderstorm downdrafts." Cold air from high up in storm clouds is much denser than relatively warmer surface air and thus it comes crashing to the surface. Once it hits the ground, the air spreads outward, much in the same fashion as pancake batter when poured onto a griddle. Often the winds blow in the same direction the storm is travelling.
Indeed on Monday Evening many experienced gusty winds well before any rain or thunder and the ominous looking low, stacked, dark cloud that precluded the winds is called a shelf cloud. The National Weather Service defines a shelf cloud as "a low, horizontal wedge-shaped cloud, associated with a thunderstorm gust front. A rising cloud motion often can be seen in the leading part of the shelf cloud, while the underside often appears turbulent, boiling, and wind-torn." Because shelf clouds are so low and thick, blocking the sun's light, they often appear very dark.
The gust front can also be detected on radar. Notice in the attached image the white arrows pointing towards a narrow strip of precipitation just out ahead of the main batch of rain. This is the thick, turbulent cloud associated with the gust front that contains just a little bit of rain within.
Many around the area snapped photos of these weather features on Monday Evening. Remember anytime you see weather happening to send us those shots via firstname.lastname@example.org or on Twitter @Josh_Eachus, @RG3WBRZ and @Pat_Shingleton.
You can get forecasts from Meteorologist Josh Eachus weekdays on 2une-In from 5-7am and News 2 at Noon from 12-1pm. Additionally, you can get the fastest and latest forecasts and weather news by checking in with wbrz.com/weather, connecting with Josh on Google+ and following him on Twitter.
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