The state of Florida has suffered its second direct hit by a tropical cyclone in as many days. On Thursday August 12, 2004, Bonnie came ashore in the Florida panhandle near Apalachicola as a tropical storm. Charley, however, became far a more dangerous Category 4 storm before it slammed into the southwest coast of Florida. Just as it did with Bonnie, the Tropical Rainfall Measuring Mission (TRMM) satellite followed Charley's progress across the Caribbean and Cuba, which suffered a direct hit. The images and data collected by TRMM can provide valuable estimates of storm location and storm intensity to the NOAA Tropical Prediction Center (also known as the National Hurricane Center).
Similar to Bonnie, Charley began as a tropical depression near the Windward Islands. Tropical depression number three (TD #3) formed on August 9th, 2004 just to the southeast of Grenada. TD #3 then moved west-northwest into the lower eastern Caribbean and strengthened into a tropical storm on the morning (local time) of the 10th. The image shown above was taken at 05:43 UTC (1:43 am EDT) on 10 August 2004. The image displays the horizontal distribution of rain intensity obtained from the TRMM satellite. Rain rates in the center part of the swath are from the TRMM Precipitation Radar (PR), the first and only precipitation radar in 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). The image shows Charley just before it became a named tropical storm. The storm appears rather small with no apparent banding in the rain field. But, most of the rain (green moderate and blue light) is concentrated near the center and IR data (white background) indicates that there is good outflow with the storm.
Charley continued moving west-northwest into the central Caribbean and slowly strengthened into a minimal Category 1 hurricane on the afternoon (local time) of the 11th with maximum sustained winds reported at 65 knots (75 mph) based on measurements by an Air Force Reserve Hurricane Hunter Aircraft. At this point, Charley was just south of Jamaica. The storm now began to curve towards the right taking a more northwestward track as it passed around the western side of a subtropical ridge to its north. Charley continued to slowly intensify. Early on the afternoon of the 12th (local time), Charley became a Category 2 hurricane with sustained winds of 85 knots (98 mph). Charley then turned even more to the north ahead of an upper-level trough and headed straight for western Cuba. On the evening of the 12th of August, Charley passed just to the east of the Isle of Youth and slammed into western Cuba where it crossed the island just west of Havana before emerging into the southeastern Gulf of Mexico. The image taken at 04:32 UTC (12:32 am EDT) on Friday August 13 shows Charley directly over Cuba. The PR missed the center of the storm but a perfectly symmetrical ring of moderate rain (green circle) marks the center of Charley by the TMI. The rain field appears tightly concentrated near the center which is surrounded by an area devoid of rain known as a dry slot showing where drier air has been entrained into the storm's circulation. At the time of this image, Charley's sustained winds were 90 knots (104 mph). After coming off of Cuba, Charley intensified into a powerful Category 4 storm, with sustained winds measured at 145 mph, before slamming into the southwest coast of Florida near Captiva Island.
TRMM is a joint mission between NASA and the Japanese space agency JAXA.
Images produced by Hal Pierce (SSAI/NASA GSFC) and caption by Steve Lang (SSAI/NASA GSFC), NASA's Tropical Rainfall Measuring Mission.