Cold Front at Sea

April 24, 2012

Santos anchorage 08 Sep 2009_ (2)

Photographer: Andreas M. van der Wurff 
Summary Authors: Andreas M. van der Wurff; Jim Foster

April 2012 Earth Science Picture of the Day Viewer's Choice The storm cloud shown above was associated with the passage of a strong cumulonimbus gust front. It was observed near sundown while at anchorage off the coast of Brazil, awaiting berth in the Port of Santos. The wind before the front arrived was just a gentle breeze (Bf 3 on the Beaufort Scale), however, as the frontal boundary crossed the bow of our ship, about 6 minutes after the photo was snapped, wind gusts over 60 mph (96 km/h) were recorded (Bf 10/11 on the Beaufort Scale). The air temperature dropped noticeably during the passage of the gust front and rain, then rose again an hour or so later. To get an idea of the size of the cloud, note the container vessel on the left side of the picture. Photo taken on September 8, 2009. [Revised November 2017]

Photo Details: Canon EOS 400D camera; EF 24-105mm; f/4.0.