July 13, 2011 - Tropical Storm Three off the western coast of Mexico

Tropical Storm Three off the western coast of Mexico

This true-color image was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Aqua satellite on July 8, 2011 at 20:35 UTC (4:35 p.m. EDT) when Hurricane Calvin was still a tropical storm off the western coast of Mexico. Within the next half-hour, at approximately 5 p.m. EDT the storm had gathered enough strength to become a Category 1 hurricane, with maximum sustained winds near 65 knots (75 mph/120 kmh). At that time, it was located about 240 miles south-southwest of Cabo Corrientes, Mexico.

Hurricane Calvin formed on July 5 as a broad low pressure area associated with thunderstorms and showers south of the Gulf of Tehuantepec. By July 7, it had organized enough that the National Hurricane Center (NHC) named the system Tropical Depression Three-E.

After a brief time at Category 1 Hurricane status, Calvin weakened quickly. By July 9, the storm was once again below hurricane strength, with maximum sustained winds of 50 knots (57 mph/93 kmh). By July 10, Calvin’s winds were reduced to 30 knots (34 mph/55 kmh), putting it in a tropical depression status. The National Hurricane Center ceased posting advisories for the storm on that same day.

By July 11, all signs of deep and strong convection, which is rapidly rising air that forms the thunderstorms that would power strengthening, were no longer visible on satellite imagery. The center of the post-tropical low was just west of Isla Clarion, with maximum sustained winds between 20 and 25 knots. The storm was reduced to wispy clouds and dissipated on July 12.

Image Facts
Satellite: Aqua
Date Acquired: 7/8/2011
Resolutions: 1km ( B), 500m ( B), 250m ( B)
Bands Used: 1,4,3
Image Credit: Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC