On 18 August 2011 at 0307 UTC (11:07 PM EDT) the TRMM satellite traveled above an area of organized shower activity in the Caribbean Sea that the National Hurricane Center (NHC) forecasts will soon become a tropical cyclone. TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) data show that this tropical wave south of Jamaica contained several areas of convective thunderstorms that were dropping rainfall at the rate of over 40 mm/hr (~1.6 inches). TRMM's PR data show that some thunderstorm towers in this stormy area were higher than 13 km (~8 miles).

A tropical depression (7E) off the southern coast of Mexico was upgraded by the National Hurricane Center (NHC) to tropical storm Greg shortly after the TRMM satellite saw it on 17 August 2011 at 0534 UTC. TRMM's Microwave Imager (TMI) showed that intense convective thunderstorms within the developing storm were dropping rainfall at rates greater than 30mm/hr (1.2 inches) in an area near the center of the storm. Greg is expected to enhance rainfall over the southwest coastline of mexico for the next day or so. Greg is forecast by the NHC to intensify to hurricane strength within 24 hours while

The High Gain Antenna System (HGAS) onboard the GPM Core Observatory finished acoustics and post-environmental deployment testing at NASA Goddard Space Flight Center. The HGAS will then undergo Thermal Vacuum testing before it is completed and delivered in mid-September. The below video shows a test of the High Gain Antenna System as it will deploy once in orbit aboard the GPM Core Observatory. Learn more about the HGAS and the GPM Core Observatory