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All eyes are on Tropical Storm Katrina as it nears the south Florida coastline. The storm, which is in the process of strengthening as it passes over the warm waters of the Gulf Stream, is forecast to become a Category 1 hurricane by the time it makes landfall. But, as it is already close to the Florida coast, it will not have time to develop into a major hurricane. However, the storm is moving very slowly, which poses a risk for flooding. Katrina formed into a tropical depression (TD #12) from a broad area of low pressure in the central Bahamas on the afternoon of 23 August 2005 (LST). Over the next day, the system slowly moved northwest through the central Bahamas, becoming a minimal tropical storm on the morning (LST) of the 24th. Katrina then turned westward and started to intensify as it passed south of Grand Bahama Island on a heading for south Florida. The Tropical Rainfall Measuring Mission (TRMM) satellite was launched back in November of 1997 to measure rainfall over the global Tropics but has proven itself to be instrumental in observing tropical cyclones. This first image was taken at 04:34 UTC (12:34 am EDT) on 25 August 2005 as Katrina was passing south of Grand Bahama Island. The image above displays the horizontal distribution of rain intensity within Katrina as obtained from TRMM's sensors. Rain rates in the center part of the swath are from the TRMM Precipitation Radar (PR), the only radar capable of measuring precipitation from space. The PR can provide fine resolution rainfall data and details on the vertical structure. Rain rates in the outer swath are from the TRMM Microwave Imager (TMI). The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). At the time of the image, Katrina was a tropical storm with maximum sustained winds reported at 45 knots (52 mph) by the National Hurricane Center (NHC). In this image, an eye is visible along the western side of the central area of precipitation (blue ring). Most of the rainfall, however, is east of the center (green and blue area). Although, there is evidence of banding in the surrounding rain areas, the banding is not as distinct as with a more mature system. Also, rainfall in the eyewall is still fairly weak. These features indicate that Katrina is still in the process of organizing.