The National Hurricane Center (NHC) upgraded an area of disturbed weather in the Caribbean to tropical depression eighteen and then to tropical storm Rina on 23 October 2011. The TRMM satellite flew over the forming tropical cyclone on 23 October 2011 at 1728 UTC (1:28 PM EDT). Data from TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) showed that the future storm already was well organized and had a large area of heavy rainfall extending toward the northeast from eastern Honduras.