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.