Typhoon Conson began as a weak tropical depression
almost 12 days ago in the West Pacific south of the western Caroline
Islands. The system moved steadily west-northwest without gaining any
strength as it passed through the central Philippines. On the 2nd of June
2004, Conson emerged into the South China Sea west of the Philippines.
Between the 4th and 7th, Conson traversed a slow loop over the South China Sea
west of the main northern island of Luzon and strengthened into a tropical
storm. On the 7th, Conson began moving towards the north-northeast and
gathered enough strength to become a typhoon. The system continued its movement
towards the north-northeast on the 8th bringing it closer to southern Taiwan.
The system also continued to strengthen. On the 9th, Typhoon Conson passed
through the Bashi Channel just south of Taiwan before passing east of the
The Tropical Rainfall Measuring Mission (TRMM) satellite captured these
images of Conson showing the storm's evolution from a tropical storm into a
typhoon. The first image was taken at 17:32 UTC on 5 June 2004. It shows
the horizontal distribution of rain intensity. Rain rates in the center
swath are from the TRMM Precipitation Radar (PR), while 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). At the time of the first image, Conson still just a tropical
storm with winds estimated at 45 knots (52 mph) by the Joint Typhoon
Warning Center. TRMM shows that the storm has a well-defined circulation
but lacks a complete eyewall with only moderate (green) rain intensities
immediately west of the center. Isolated heavier rain (red areas) occurs
in the outer rainbands. The next image taken at 16:24 UTC on the 8th
shows a much stronger storm. The rainbands are tightly wrapped around
the center which now contains intense (dark red areas) rain areas in the
northern and eastern part of the eyewall. These intense rainrates show
where heat is being released that fuels the storm. The typhoon is now
over the Luzon Straight between the northern Philippines and southern
Taiwan and has winds of 90 knots (104 mph). The next image was taken at
the same time and shows a vertical slice through the center of the storm
looking east. It shows the convection on the east side of the storm is
much taller (blue areas above the yellow areas) and more intense (dark
red area) than on the west side.
The last set of images were taken at 16:14 UTC on the 10th as Conson was
approaching the southern islands of Japan. At this time, Conson is
starting to become extratropical as it accelerates to the northeast. The
top down image reveals that the center has become ragged and disorganized.
Some intense rainfall (dark reds) still exists north of the center and in
a trailing rainband. The vertical slice taken through the convection north
of the center looking east shows an area of intense rain (dark red area)
and evidence of a bright band (horizontal red/yellow layer). Bright bands
are brought about by melting of larger ice particles. This final image
also shows that the convective towers are not as deep as they were earlier
(blue areas above the yellow areas).
TRMM is a joint mission between NASA and the Japanese space agency JAXA.