NASA eyes Tropical Cyclone Annabelle in Southern Indian Ocean

November 23, 2015

Tropical Storm Annabelle formed early on Nov. 21 in the Southern Indian Ocean, strengthened briefly and began a weakening trend on Nov. 23. NASA's Terra satellite and RapidScat instrument captured imagery of the storm after it developed.

Early on Nov. 21, Annabelle, the third tropical cyclone of the Southern Indian Ocean season, formed near 10.9 south latitude and 71.6 east longitude, about 234 nautical miles south-southwest of Diego Garcia.

At 05:35 UTC (12:35 a.m. EST), NASA's Terra satellite captured a visible image of Tropical Cyclone Annabelle. As the storm was intensifying, the MODIS instrument aboard Terra saw thick bands of thunderstorms wrapping into the low-level center of circulation from the north and northeast of the center.

On the same date, when the International Space Station passed over Annabelle, NASA's RapidScat instrument measured the maximum sustained winds around Annabelle's center. Strongest winds were near 30 meters per second (67 mph/108 kph).

On Nov. 22, the Atmospheric Infrared Sounder or AIRS instrument aboard NASA's Aqua satellite captured an image of Annabelle's cloud-top temperatures. Coldest cloud tops near -63F/-53C and strongest storms were around the center of circulation. Those cloud tops warmed on Nov. 23 as the storm weakened.

On November 23 at 1500 UTC (10 a.m. EST) Tropical Cyclone Annabelle's maximum sustained winds had decreased to near 55 knots (63.2 mph/101.9 kph). It was centered near 16.7 degrees south latitude, and 76.7 degrees east longitude, about 626 nautical miles south of Diego Garcia and moving further away. Annabelle was moving to the southeast at a speedy 23 knots (26.4 mph/42.6 kph).

Tropical Storm Annabelle is on a weakening trend. Forecasters at the Joint Typhoon Warning Center noted that the storm has "become significantly elongated as it interacts with an approaching mid-latitude trough (elongated area of low pressure) and the associated high northwesterly vertical wind shear. The convection (developing storms) has started to weaken with warming cloud tops evident in the enhanced infrared satellite loop." When cloud tops warm on infrared satellite imagery, it means they are not being pushed as high in the troposphere (lowest level of the atmosphere). That indicates the storm has become weaker.

The Joint Typhoon Warning Center expects Annabelle to weaken to a depression by Nov. 25 and dissipate shortly thereafter.

NASA/Goddard Space Flight Center

Related Tropical Cyclone Articles from Brightsurf:

NASA finds post-Tropical Cyclone Dolly exiting the tropical stage
NASA's Terra satellite provided a night-time look at what is now Post-Tropical Storm Dolly in the Northern Atlantic Ocean.

NASA find Herold a fading ex-tropical cyclone
Former Tropical Cyclone Herold is now a fading area of low-pressure in the Southern Indian Ocean and NASA's Aqua satellite provided forecasters with a visible image.

NASA sees Tropical Cyclone Herold's eye
NASA's Aqua satellite passed over the Southern Indian Ocean and captured an image of a well-developed Tropical Cyclone Herold at hurricane strength, east of Madagascar.

A new method to improve tropical cyclone intensity forecasts
There are many reasons for model errors in numerical weather forecasting of tropical cyclone intensity.

NASA catches the dissipation of Tropical Cyclone Claudia
Tropical Cyclone Claudia was dissipating in the Southern Indian Ocean when NASA's Terra satellite captured a visible image of storm as it flew overhead in its orbit around the Earth.

NASA finds tropical cyclone 02S consolidating
NASA's Aqua satellite captured an image of Tropical cyclone 02S and the visible image showed that the storm was getting better organized.

NASA finds Tropical Cyclone's Vayu getting stretched
When NASA's Aqua satellite passed over the Northern Indian Ocean, it captured an infrared image that revealed Tropical Cyclone Vayu was elongating.

NASA takes Tropical Cyclone's Vayu's temperature
NASA's Aqua satellite passed over the Northern Indian Ocean and took the temperature of Tropical Cyclone Vayu as it moved northward in the Arabian Sea.

NASA catches development of Tropical Cyclone 02A
Visible imagery from NASA's Terra satellite provided confirmation of the development of Tropical Cyclone 02A in the Arabian Sea, Northern Indian Ocean.

NASA goes infrared on powerful Tropical Cyclone Fani
NASA's Aqua satellite focused an infrared eye on a very powerful Tropical Cyclone Fani as it approached landfall in northeastern India.

Read More: Tropical Cyclone News and Tropical Cyclone Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to