The Tropical Rainfall Measuring Mission (TRMM) satellite captured this remarkable image of two tropical storms in the eastern Pacific--Nora and Olaf--in the same overpass. Taken on 6 October 2003 at 20:14 UTC, the image shows Tropical Storm Nora on the left and Tropical Storm Olaf on the right. Nora became a tropical storm on October 2 and strengthened into a Category 2 hurricane with estimated winds of just over 100 mph on the 4th before weakening again into a tropical storm on the 6th. Olaf became a tropical storm on the 3rd of October, a minimal Category 1 hurricane on the 5th, and also weakened back to a tropical storm on the 6th.
The image shows an instantaneous snapshot of the rainfall rates for both storms as seen by the TRMM Precipitation Radar (PR) in the inner swath and TRMM Microwave Imager (TMI) in the outer swath. The rainrates are overlayed on a visible image from the TRMM Visible Infrared Scanner (VIRS). Despite the impressive swirl of cloudiness, TRMM reveals that Nora is devoid of any significant rainfall. The core no longer contains any convection to support the storm and indicates that Nora will likely continue to weaken. Olaf however does contain areas of intense rainfall (darker reds) that are helping to maintain the storm. However, due to its poor organization and close proximity to the west coast of Mexico, Olaf has little chance to strengthen much.
TRMM is a joint mission between NASA and the Japanese space agency NASDA.
Image produced by Hal Pierce (SSAI/NASA GSFC) and caption by Steve Lang (SSAI/NASA GSFC).