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Precipitation Radar Vertical Slice from The WEST (click to Enlarge)

The Tropical Rainfall Measuring Mission (TRMM) satellite captured these images of Tropical Storm Erika just as it was getting organized in the eastern Gulf of Mexico. The images were taken at 4:15 pm EDT (20:15 UTC) on the 14th of August, 2003. At the time Erika was not yet a named storm but was named less than an hour after these images were taken by the National Hurricane Center with maximum sustained winds of 40 mph. Erika formed from an easterly wave disturbance after moving from the Bahamas across the Florida penisula. Over the open warm waters of the Gulf, the system began to gain strength and became better organized in a relatively low wind-shear environment. The first image shows a top down view of the storm. Rainfall rates from the TRMM Precipitation Radar (PR) in the inner swath and the TRMM Microwave Imager (TMI) in the outter swath are overlayed on TRMM Visible Infrared System (VIRS) data (white areas) and show bands of convection feeding into the storm. The center is open and does not yet have a well-defined eye. The blue, green, yellow and red areas indicate increasing rainfall insenity. The second image shows a vertical slice taken by the PR through the northeast side of the storm indicating areas of heavy (darker reds) and light rain (blue and green areas). At the time, the storm was moving quickly the west at 21 mph under the influence of high pressure to the north.

TRMM is a joint mission between NASA and the Japanese space agency NASDA.

Images produced by Hal Pierce (SSAI/NASA GSFC) and caption by Steve Lang (SSAI/NASA GSFC).