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Hurricane Season 2009: Tropical Depression 8 (Atlantic)
09.28.09
 
September 28, 2009

NASA's AIRS instrument captured an infrared image of TD#8s cold clouds on September 26, at 12:05 a.m. EDT. > View larger image
NASA's AIRS instrument captured an infrared image of TD#8s cold clouds on September 26, at 12:05 a.m. EDT, and the system was not well organized, and didn't show much strong convection.
Credit: NASA/JPL, Ed Olsen
Atlantic Tropical Depression 8 Comes and Goes in a Weekend

Tropical Depression Eight didn't have much of a lifetime in the far eastern Atlantic Ocean. In fact, it formed after working hours (Eastern Time) on Friday September 25 and faded away about 24 hours later.

Tropical depression eight (TD#8) formed on Friday, September 25 at 5 p.m. EDT near latitude 17.4 north and longitude 32.3 west or about 560 miles west of the Cape Verde Islands. TD#8 had maximum sustained winds near 35 mph, and was moving northwest near 14 mph.

The depression experienced 11-17 mph (10-15 knots) of southwesterly vertical wind shear late on Friday night, and those winds increased over the weekend, keeping the storm below tropical storm strength. Adding more challenge to the storm's development were cooler sea surface temperatures (cooler than the 80F needed to keep it going). Those two factors led to TD#8's short lifetime.

NASA's Aqua satellite flew over TD#8 shortly after midnight on September 26, and its Atmospheric Infrared Sounder (AIRS) instrument captured an image of the storm's cold clouds. The system was not well organized, and didn't show much strong convection.

By 5 p.m. EDT on Sunday, September 26, TD#8 became a remnant low pressure area near 18.9 north and 35.7 west. Its maximum sustained winds were down to 25 knots (28 mph), and its minimum central pressure was near 1008 millibars. The depression has since officially dissipated.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



September 25, 2009

The GOES-12 satellite captured a visible image of low pressure area that may develop into a tropical cyclone this weekend. The GOES-12 satellite captured a visible image of low pressure area (center of image) on September 25 at 2:15 p.m. EDT, that may develop into a tropical cyclone this weekend in the far eastern Atlantic Ocean. Western Africa is seen to the far right.
Credit: NASA/NOAA GOES Project
Another Tropical Depression in Far Eastern Atlantic?

Satellite imagery has provided clues that a new tropical cyclone is forming in the far eastern Atlantic Ocean.

At 2 p.m. EDT today, Friday, September 25, 2009 showers and thunderstorms have become better organized in a tropical wave. The area of showers and thunderstorms is located about 400 miles west of the Cape Verde Islands.

The National Hurricane Center noted "A tropical depression could form in this area during the next 24 hours before upper-level winds become less conducive. There is a high chance...greater than 50 percent...of this system becoming a tropical cyclone during the next 48 hours." If the storm strengthens to a tropical storm over the weekend, it would get the name "Grace."

GOES-12, the Geostationary Operational Environmental Satellite provided a visible image of the low pressure area's clouds at 2:15 p.m. EDT on September 25, 2009. GOES-12 is operated by the National Oceanic and Atmospheric Administration, and images are created by NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center