April 5, 2010
Tropical Storm Robyn Nested Away From Land
Tropical Storm "Robyn" didn't have to fly south for the northern hemisphere winter, like the birds (Robins), it formed in the southern hemisphere this past weekend in the Southern Indian Ocean. Infrared satellite imagery from NASA's Aqua satellite revealed that the storm's strong thunderstorms and heavy rainfall are safely "nested" over open waters.
Formerly tropical depression 23S, Robyn strengthened into a tropical storm this weekend. As of Monday, April 5, Robyn had maximum sustained winds near 60 knots (69 mph) gusting to 75 knots (86 mph). It was located about 370 nautical miles southwest of Cocos Islands, Australia, near 16.1 South and 92.0 East. Robyn was moving south-southeast at 7 mph (6 knots) and as it moves it is kicking up waves up to 18 feet high.
NASA's Aqua satellite has been flying over Tropical Storm Robyn since it developed on Friday, April 2. The Atmospheric Infrared Sounder (AIRS) instrument captured infrared imagery of the storm that showed high, cold, thunderstorm cloud tops as cold as -63 Fahrenheit (-52 Celsius). That data helped forecasters see that Robyn had powerful rain-making thunderstorms. AIRS provided valuable infrared data on Robyn's cloud top temperatures, which are important because they tell forecasters how high thunderstorms are and the rule is: the higher the thunderstorm, the more powerful the tropical cyclone. AIRS imagery revealed this morning that deep convection (rapidly rising air that condenses and forms thunderstorms that power a tropical cyclone) has decreased. Meanwhile, the low-level center of circulation continues to remain well-organized and the strongest winds are in the southwestern quadrant of the storm.
The Joint Typhoon Warning Center noted that Robyn's movement southeastward is taking the tropical storm further into an area of higher vertical wind shear (which can weaken and tear the storm apart). As a result, Robyn is expected to weaken over the next three days while remaining at sea.
Image 1: NASA's Aqua satellite flew over Tropical Storm Robyn on April 2, 1929 UTC and the Atmospheric Infrared Sounder instrument captured an infrared image of the storm's cloud temperatures. The images showed high, cold, thunderstorm cloud tops (purple) as cold as -63 F. Credit: NASA JPL, Ed Olsen
Image 2: The Atmospheric Infrared Sounder instrument on NASA's Aqua satellite captured a visible image of Tropical Storm Robyn on Monday, April 5, at 0729 UTC (3:29 a.m. EDT). The white areas on the sides of the image are outside of the "vision" of the AIRS instrument as the satellite passed over the storm from space. Credit: NASA JPL, Ed Olsen
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