NASA Satellite Sees Strong Wind Shear Taking Final Toll On Tropical Storm 5A

November 30, 2011

For the last two days, strong wind shear in the Arabian Sea has pushed most of the clouds and showers associated with Tropical Storm 5A away from its center. Today, Nov. 30, NASA satellite imagery shows wind shear continues to push those clouds to the north and west of 5A’s center and is taking a big toll on the entire cyclone.

At 03:00 UTC on Nov. 30 (or 10 p.m. EST, Nov. 29), the Joint Typhoon Warning Center issued their final advisory on Tropical Storm 5A (5A). At that time, it was about 485 nautical miles (558 miles/898 km) south-southeast of Karachi, Pakistan near 17.5 North latitude and 63.8 East longitude. 5A’s maximum sustained winds were still holding at 35 knots (40 mph/65 kmh) but wind shear was battering and weakening the storm. 5A was moving westward at 11 knots (13 mph/20 kmh) and is expected to turn to the southwest on Dec. 1.

Infrared imagery from NASA’s Atmospheric Infrared Sounder (AIRS) instrument on the Aqua satellite showed a partially exposed low level center of circulation today, and the strongest convection and thunderstorms over the Tropical Storm 5A’s western quadrant. The convection (rapidly rising air that forms those thunderstorms that make up the storm) is waning because it continues to be battered by southerly vertical wind shear between 20 and 30 knots (23 and 35 mph/ 37 and 55 kmh). There were also no bands of thunderstorms visible in the AIRS infrared image, another indication that the storm was weakening.

The Joint Typhoon Warning Center (JTWC) has forecast Tropical Storm 5A to turn to the southwest tomorrow, December 1 as a result of a shortwave trough (elongated area of low pressure) that will push it in that direction. The trough will steer Tropical Storm 05A away from the Oman coast. JTWC also expects 5A to dissipate late in the day tomorrow.

Image Caption: NASA’s Terra satellite flew over the Arabian Sea on Nov. 30, 2011 at 06:40 UTC (1:40 a.m. EST) and captured a visible image of Tropical Storm 5A. The image showed a large extent of clouds (about 200 miles) from 5A’s northern quadrant. Credit: NASA Goddard MODIS Rapid Response Team

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Source: NASA/Goddard Space Flight Center

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