Monday, August 11, 2008

Accuweather - Two "Features" could become tropical systems this week

Atlantic Becoming More Active (August 11th 2008 at 9:30pm)

We are keeping a close eye on two features in the southern North Atlantic that might become organized tropical systems within the next few days. One feature is located about 700 miles east of the Lesser Antilles along 47 west with a broad area of low pressure centered near 13 north. This low pressure area and the clouds, showers and thunderstorms attempting to wrap around it have been moving west-northwest at about 10-15kts. Computer simulations suggest this feature will attempt to organize over the next few days and could become an organized tropical feature by the time it nears the Leeward islands on Thursday. Surface temperatures are near 80 degrees Fahrenheit and upper-level winds are favorable. The only limiting factor is drier air to the north and northwest. If this dry air gets drawn into the low pressure area this could prevent thunderstorms from wrapping around the system.

The second feature we are watching is located along 30 west with a surface low near 11 north. This is roughly 450 miles southwest of the Cape Verde islands. Visible satellite images during Monday afternoon were showing a swirling cloud mass including some banding clouds. Banding clouds suggests convective showers and thunderstorms are arcing around a common center, a sign the system is trying to organize in the lower and upper levels. If this banding process continues, the system could become a tropical depression within the next day or two. The system is moving west northwest at about 10-15kts over relatively warm water. It will pass over an area of cooler water over the next 24 hours then should be in favorable warm water. The system is riding on the northern fringes of stronger wind shear which could have some affect on its development. But the shear should relax as it moves farther east. If this system can outrun the shear and move into warmer water, then it could become a depression within the next day or two.

By AccuWeather Expert Senior Meteorologist Dan Kottlowski

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