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 island.
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.
Images produced by Hal Pierce (SSAI/NASA GSFC) and caption by Steve Lang (SSAI/NASA GSFC), NASA's Tropical Rainfall Measuring Mission.
