Public Release: 

Satellite shows Tropical Depression 9 weakening

NASA/Goddard Space Flight Center

NOAA's GOES-East satellite captured an image of Tropical Depression 9 weakening in the Central Atlantic on September 18, 2015. Tropical Depression 9 is battling wind shear and dry air, both of which are taking the life out of it.

NOAA's GOES-East satellite provides continuous coverage of the Atlantic and eastern U.S. and on September 18 at 0845 UTC (4:45 a.m. EDT) saw the fading Tropical Depression 9. Forecaster Beven of the National Hurricane Center noted that the satellite imagery showed a burst of convection with cloud tops colder than -70C had developed near and northeast of the center of Tropical Depression Nine. However, strong vertical wind shear continues to affect the storm. The image was created by the NASA/NOAA GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

At 500 AM AST (0900 UTC), the center of Tropical Depression Nine was located near latitude 17.6 North, longitude 45.7 West. The depression is moving toward the north-northwest near 7 mph (11 kph). A motion toward the northwest is expected during the next 48 hours.

Maximum sustained winds are near 30 mph (45 kph) with higher gusts. The depression is moving through an area of strong upper-level winds, and it is forecast to weaken to a remnant low Friday or Friday night (September 18).The estimated minimum central pressure is 1007 millibars.

Beven said the depression continues to be in an environment of 25 to 30 knot of westerly vertical wind shear, and water vapor imagery shows mid- to upper-level dry air is moving into the depression. Both of those factors are weakening the depression. The dynamical computer forecast models suggest those conditions should persist for at least 48 hours, and based on this the depression is forecast to degenerate to a remnant low pressure area in 24 hours or less.


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