NASA examines Tropical Cyclone Dumazile’s flooding rainfall
Tropical cyclone Dumazile formed east of Madagascar on March 3, 2018 and brought soaking rainfall to Madagascar. The GPM or Global Precipitation Measurement mission core satellite obtained a look at the soaking Dumazile gave the island nation.
The tropical cyclone has caused flooding as it moved parallel to Madagascar's eastern coast. The clockwise rotation of the tropical cyclone has been transporting bands of rain onto Madagascar. Over 210 mm (8.3 inches) of precipitation was reported along the northeastern coast of Madagascar.
The GPM core observatory satellite passed over eastern Madagascar on March 3, 2018 at 12:10 a.m. EST (1710 UTC). Tropical Cyclone Dumazile was located in the Indian Ocean east of northeastern Madagascar. When GPM passed overhead, the tropical cyclone was intensifying and was close to typhoon power but the eye didn't form until a day or two later.
The GPM satellite, managed by both NASA and the Japan Aerospace Exploration Agency, JAXA, collected data that showed Dumazile contained bands of extremely heavy rainfall. As the satellite flew overhead GPM's Microwave Imager (GMI) and Dual Frequency Precipitation Radar (DPR) collected data that showed an intense band of rain hitting Madagascar's eastern coast. GPM's radar (DPR Ku Band) data showed that a powerful storm in this rain band was dropping rain at a rate of over 160 mm (6.3 inches) per hour. Even heavier precipitation was spotted by the satellite in other storms approaching the coast. GPM's DPR data indicated that one of these storms was producing rain at a rate of over 216 mm (8.5 inches) per hour.
At NASA's Goddard Space Flight Center, in Greenbelt, Md. a 3-D view using GPM data showed the precipitation structure in Dumazile's rain bands were hitting eastern Madagascar. GPM's radar measurements of storms within those rain bands showed that Tropical Cyclone Dumazile was generating storms with heights above 13.7 km (8.5 miles).
On March 6 at 5:12 a.m. EST (10:12 UTC), the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA's Suomi NPP satellite provided a visible look at Tropical Cyclone Dumazile, located off Madagascar's southeastern coast. The VIIRS image showed that the eye had become cloud-filled and disappeared.
On March 6, 2018 at 10 a.m. EST (1500 UTC), Tropical Cyclone Dumazile's maximum sustained winds dropped to 95 knots (109.3 mph/180 kph). Dumazile continued to move away from Madagascar and was centered near 4.6 degrees south latitude and 54.0 degrees east longitude, about 241 nautical miles south-southwest of St. Denis, La Reunion. Dumazile was moving to the southeast at 13 knots (15 mph/24 kph) and is expected to continue tracking in that direction over the next couple of days.
The Joint Typhoon Warning Center or JTWC noted that animated multispectral satellite imagery, that can peer through clouds showed that Dumazile still maintained a 10-nautical mile wide eye that appeared cloud-filled in Suomi NPP's visible imagery. Feeder bands of thunderstorms remained tightly wrapped into the low-level center but had become more shallow and asymmetric.
The Joint Typhoon Warning Center predicts that the tropical cyclone will weaken while moving southeastward. Cooler sea surface temperatures and increasing vertical wind shear are then expected to cause Dumazile to rapidly weaken.