After brushing the southern tip of the island of Madagascar, Cyclone Favio continued westward, striking Mozambique on the morning of 22 February 2007 as a strong Category 3 storm. So far, 4 fatalities have been reported in Vilanculos, a coastal tourist town where the storm made landfall.

Favio began as a tropical disturbance back on the 11th of February 2007 in the central Indian Ocean south of Deigo Garcia in the Chagos Archipelago. Slow to intensify, the system finally became a tropical storm three days later on the 14th as it was moving southwest through the central Indian Ocean. Favio remained a tropical storm for the next several days as it made its way through the west-central Indian Ocean east of Mauritius in the general direction of southern Madagascar. Favio finally began to intensify as it neared Madagascar and became a Category 1 cyclone on the 19th. As it rounded the southern tip of Madagascar, Favio continued to intensify and reached Category 3 intensity during the day on the 20th. The cyclone then took a more northwesterly path as it entered the Mozambique Channel.

The Tropical Rainfall Measuring Mission (TRMM) satellite was placed into its low-earth orbit in November of 1997. Its primary mission is to measure rainfall from space; however, it has also served as a valuable platform for monitoring tropical cyclones, especially over remote parts of the open ocean. These images of Favio were captured by TRMM just as the powerful storm was moving away from Madagascar. The images were taken at 14:29 UTC on 20 February 2007. The first image shows the horizontal distribution of rain intensity looking down on the storm. Rain rates in the center of the swath are from the TRMM Precipitation Radar (PR), while those in the outer portion are from the TRMM Microwave Imager (TMI). The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). TRMM shows that Favio is a well-organized storm with a central eye (dark blue area in the center) surrounded by an eyewall containing heavy rainfall (dark red areas). The storm is also very symmetric with good banding in the rain field as evidenced by the tightly-curved bands of moderate rain (green areas) spiraling in towards the center. These features are the hallmarks of a mature, intense tropical cyclone.

The next TRMM image was taken at the same time as the previous image and shows a 3D perspective of Favio using data collected from the TRMM PR. The higher tops are indicated in red. Deep convective towers that are part of the eyewall form a ring around the center. These can be a precursor to future strengthening. Tropical cyclones act like large heat engines. Their fuel comes from the transformation of water vapor in the atmosphere. As water vapor condenses into the tiny cloud droplets that eventually form the precipitation, heat is released. This heat, known as latent heat, is what drives the storm's circulation. In general, the more heating that occurs, the more intense the storm will become. This heating is most effective in driving the storm if it is occurs near its center. Indeed Favio would continue to strengthen after these images were taken. At the time of these images Favio was a Category 3 cyclone with maximum sustained winds estimated at 105 knots (121 mph) by the Joint Typhoon Warning Center. Although the center of Favio never made landfall in Madagascar, the storm brought heavy rains to the southern part of island.

As Favio crossed the Mozambique Channel it reached a peak intensity of 125 knots (144 mph) on the early morning of the 22nd, making it a Category 4 storm. The cyclone then weakened slightly before slamming into southern Mozambique with sustained winds estimated at 110 knots (127 mph). The final image was taken by TRMM at 20:44 UTC on the 22nd soon after Favio made landfall in Mozambique. TRMM shows that although the eye is not as well defined as in the earlier image, the circulation is still robust as seen by the well-defined curvature in the spiral rainbands (green arcs). Maximum sustained winds were still estimated to be 90 knots (114 mph) at the time of this image but quickly diminished thereafter. Unfortunately for Mozambique, the rains from Favio are not welcome as the country has been experiencing flooding over the past several weeks, which could be exacerbated by Favio.



See a 3-D flyby of the 15dBZ isosurface image



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).