000
AXNT20 KNHC 120004
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE AUG 11 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...SPECIAL FEATURES...
THE CENTER OF TROPICAL DEPRESSION TWO IS NEAR 14.6N 30.4W OR 
ABOUT 400 MILES/645 KM TO THE WEST OF THE SOUTHERNMOST CAPE 
VERDE ISLANDS. THE DEPRESSION IS MOVING WESTWARD 10 KT. THE 
MAXIMUM SUSTAINED WIND SPEEDS ARE 25 KT WITH GUSTS TO 35 KT.
PLEASE READ THE LATEST NHC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT2/WTNT22 KNHC AND THE PUBLIC BULLETIN UNDER MIATCPAT2/
WTNT32 KNHC FOR MORE DETAILS. SOME SLOW STRENGTHENING IS 
FORECAST DURING THE NEXT 24 HOURS...AND IT IS POSSIBLE THAT THE 
DEPRESSION MAY BECOME A TROPICAL STORM DURING THE NEXT DAY OR SO.
STRONG SHOWERS AND THUNDERSTORMS FROM 14N TO 15N BETWEEN 31W AND 
33W.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 19N51W 12N53W 4N54W IN 
FRENCH GUIANA MOVING WEST ABOUT 15 KT. DISSIPATING SHOWERS IN
FRENCH GUIANA TO THE SOUTH OF 5N. ISOLATED MODERATE SHOWERS...
SOME DISSIPATING WITH TIME...FROM 9N TO 17N BETWEEN 52W AND 54W.

AN EASTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 20N62W 14N63W
6N64W IN VENEZUELA MOVING WEST 10 KT. ISOLATED MODERATE SHOWERS
ARE WITHIN 60 NM TO 120 NM ON EITHER SIDE OF 20N60W 17N61W 
12N63W 9N64W. ISOLATED MODERATE SHOWERS ALSO ARE IN VENEZUELA
TO THE SOUTH OF 7N.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 77W/78W TO THE SOUTH OF
16N MOVING WEST ABOUT 15 KT. DRY AIR IN SUBSIDENCE IS AROUND
THIS WAVE. WARMING CLOUD TOP TEMPERATURES AND DISSIPATING 
PRECIPITATION ARE FROM JAMAICA TO SOUTHEASTERN CUBA BETWEEN 
SOUTHWESTERN HAITI AND 78W.

...THE ITCZ...

FROM THE COAST OF AFRICA NEAR 10N14W TO 14N27W 12N37W 13N50W TO
12N60W. ISOLATED MODERATE SHOWERS ARE WITHIN 30 NM TO 60 NM ON
EITHER SIDE OF 8N17W 9N24W 10N27W 10N30W 12N38W 13N44W 10N50W
9N52W. 

...DISCUSSION...

THE GULF OF MEXICO...
AN UPPER LEVEL TROUGH EXTENDS FROM THE FLORIDA BIG BEND TO
26N86W TO 24N89W TO 22N94W INTO THE WESTERN ISTHMUS OF 
TEHUANTEPEC OF MEXICO. ISOLATED MODERATE SHOWERS ARE FROM 23N
TO 28N. ISOLATED MODERATE SHOWERS ARE FROM GUATEMALA NORTHWARD 
INTO THE YUCATAN PENINSULA OF MEXICO...ON THE SOUTHEASTERN SIDE
OF THE TROUGH...AND TO THE WEST OF A WESTERN CARIBBEAN SEA UPPER 
LEVEL RIDGE. PRECIPITATION IS SOUTHEASTERN LOUISIANA WITH 
BROAD SURFACE LOW PRESSURE AND UPPER LEVEL DIFFLUENT WIND FLOW.

THE CARIBBEAN SEA...
UPPER LEVEL ANTICYCLONIC FLOW COVERS THE WESTERN HALF OF THE 
AREA. A WEAK UPPER LEVEL TROUGH IS MOVING NEARLY IN UNISON WITH 
THE WESTERN CARIBBEAN SEA TROPICAL WAVE...IN DRY AIR/SUBSIDENCE.
ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS COVER THE 
AREA FROM 9N TO 20N BETWEEN 82W AND 90W...IN AFTERNOON HEATING 
AND A MIDDLE LEVEL INVERTED TROUGH.

THE ATLANTIC OCEAN...
A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 31N46W TO 
25N49W...ALONG A SHEAR AXIS TO A CYCLONIC CIRCULATION CENTER 
NEAR 24N60W TO 21N67W TO 19N72W ALONG THE BORDER OF HAITI AND 
THE DOMINICAN REPUBLIC. A WEAK UPPER LEVEL TROUGH THAT IS 
SURROUNDED BY DRY AIR IN SUBSIDENCE PASSES THROUGH 30N34W
TO 13N37W.

$$
MT