The National Hurricane Center (NHC) issued it's first advisory for tropical storm Irene on 20 August 2011 at 2300 UTC (7 PM EDT). The TRMM satellite passed over the intensifying storm a little later on 22 August 2011 at 0024 UTC (8:24 PM EDT). Data collected with this orbit showed that Irene contained numerous powerful thunderstorms with TRMM's Precipitation Radar (PR) revealing that some thunderstorm towers near the center of the storm were reaching to heights above 15 km (~9.3 miles). The NHC has forecasted that Irene will become a hurricane within 36 hours while moving in a west

The TRMM satellite had an excellant daylight view of tropical storm Harvey on 20 August 2011 at 1744 UTC ( 1:44 PM EDT) as the storm was coming ashore in Belize. An Air Force Reserve aircraft reported to the National Hurricane Center that Harvey's winds had increased to 63 kts (~72.5 mph) just before landfall. TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) data show that heavy thunderstorms were occurring over land northwest of the storm's center.

An area of potential tropical cyclone formation in the Atlantic Ocean about 800 miles east of the Lesser Antilles was seen by the TRMM satellite on 19 August 2011 at 1531 UTC (11:31 AM EDT). TRMM's Precipitation Radar (PR) revealed that powerful thunderstorm towers within this tropical wave reached to heights above 15 km (~9.3 miles).

Ocean water warmer than 26C is a necessary condition for tropical cyclones to support convection. A TMI based Sea Surface Temperature (SST) analysis for three days ending on 18 August 2011 is shown above. Tropical Storm Fernanda's path (overlaid in white) recently took it over ocean waters colder than 26 Celcius so it has weakened considerably. The TRMM satellite passed over Fernanda on 19 August 2011 at 0648 UTC. The TMI and PR rainfall analysis from this pass shows that there is now very little rainfall with the weakening storm. See earlier news about Tropical Storm Fernanda

The TRMM satellite had a good daytime view of the tropical wave that was upgraded to the Atlantic Ocean basin's eighth tropical depression on 19 August 2011 at 0300 UTC (18 August 11 PM EDT). An image from TRMM's pass on 18 August 2011 at 1757 UTC (1:37 PM EDT) is displayed above and reveals that the precipitation pattern was getting a little better organized but heavy rainfall didn't cover a large portion of 08L at that time. Tropical depression 08L is predicted by the National Hurricane Center (NHC) to weaken to a remnant low in the next three days while producing rain over Honduras