Animation of Tropical Storm Fred via GPM on August 30, 2015 at 0236 UTC.
The Global Precipitation Measurement (GPM) mission core satellite passed over Tropical Storm Fred as it was developing in the Eastern Atlantic early August 30th and saw "hot towers" in the storm, which hinted that the storm was intensifying.
Fred became the first Cape Verde hurricane of the 2015 Atlantic season when it was upgraded from a tropical storm on August 31, 2015 at 0600 UTC (2 a.m. EDT). The GPM core observatory satellite flew over on August 30, 2015 at 0236 UTC when Fred was forming from a tropical wave that moved off the African coast. Rainfall was measured by GPM's Dual-Frequency Precipitation Radar (DPR) at the extreme rate of close to 128 mm (5.0 inches) per hour. Rainfall in towering convective storms at Fred's center of circulation were providing the energy necessary for intensification into a hurricane. Three dimensional reflectivity data from GPM's DPR showed that these "hot towers" had storm top heights reaching to 16.2 km (10.0 miles).
A "hot tower" is a tall cumulonimbus cloud that reaches at least to the top of the troposphere, the lowest layer of the atmosphere. It extends approximately 9 miles/14.5 km high in the tropics. These towers are called "hot" because they rise to such altitude due to the large amount of latent heat. Water vapor releases this latent heat as it condenses into liquid. Those towering thunderstorms have the potential for heavy rain. NASA research shows that a tropical cyclone with a hot tower in its eyewall was twice as likely to intensify within six or more hours, than a cyclone that lacked a hot tower.
Print resolution still of Tropical Storm Fred's precipitation amounts both on the ocean surface and in the 3D structure of the storm. Precipitation colors ranging from green to red are liquid precipitation amounts. Precipitation colors in shades of blue are frozen precipitation.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 188.8.131.52.0