000
AXNT20 KNHC 211744
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT JUN 21 2008

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 33W/34W S OF 16N MOVING W 15-20 KT. BROAD 
LOW-MID LEVEL CYCLONIC TURNING IS EVIDENT ON VISIBLE SATELLITE 
IMAGERY. LATEST ASCAT WIND DATA SUPPORTS THE WAVE POSITION. 
UPPER LEVEL FEATURES CONTINUE TO KEEP MOST OF THE CONVECTION SW 
OF THE AXIS. A SMALL CLUSTER OF MODERATE CONVECTION IS FROM 
1N-2N BETWEEN 34-35W. ADDITIONAL CLUSTERS OF SCATTERED MODERATE 
TO STRONG CONVECTION ARE WITHIN 200 NM AHEAD OF THE AXIS FROM 
4N-8N.   

TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 73W FROM HAITI 
TO COLOMBIA MOVING W NEAR 20 KT. SATELLITE IMAGERY SHOWS 
LOW-LEVEL TURNING NEAR 15N. SCATTERED SHOWERS AND THUNDERSTORMS 
ARE EAST OF THE AXIS FROM 15N-18N BETWEEN 69W-73W. THIS 
CONVECTIVE ACTIVITY IS BEING ENHANCED BY UPPER LEVEL DIVERGENCE. 

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N12W 7N24W 4N35W TO THE BORDER OF 
BRAZIL AND FRENCH GUIANA. SCATTERED MODERATE CONVECTION IS 
MOVING OFF THE COAST OF W AFRICA FROM 5N-11N E OF 22W. CLUSTERS 
OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 100 
NM N OF THE ITCZ BETWEEN 35W AND S AMERICA.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL FEATURES DOMINATE THE WEATHER PATTERN IN THE GULF 
THIS AFTERNOON. AN UPPER-LEVEL RIDGE OVER MEXICO EXTENDS INTO 
THE FAR W GULF. STRONG SUBSIDENCE AROUND THE RIDGE IS 
MAINTAINING MOSTLY CLEAR CONDITIONS IN THE SW GULF W OF 94W S OF 
25N. A SECOND UPPER RIDGE OVER THE YUCATAN PENINSULA EXTENDS 
OVER THE SE GULF. IN BETWEEN...A SHORTWAVE TROUGH COVERS THE 
NORTHERN GULF WITH ITS AXIS STRETCHING FROM THE LOWER 
MISSISSIPPI VALLEY TO THE BAY OF CAMPECHE. DIVERGENCE BETWEEN 
THIS TROUGH AND THE RIDGE TO THE SOUTH IS GENERATING A LARGE 
SWATH OF SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE CENTRAL 
AND EAST GULF EAST OF 94W. INSTABILITY AHEAD OF A SHORTWAVE 
TROUGH IS PRODUCING SIMILAR CONVECTIVE ACTIVITY WITHIN 100 NM OF 
THE COASTLINE FROM GALVESTON TEXAS TO FORT MEYERS FLORIDA. A 
WEAK PRESSURE PATTERN IS PROVIDING LIGHT WINDS ACROSS THE REGION.

CARIBBEAN...
UPPER LEVEL MOISTURE FROM THE PACIFIC IS STREAMING ACROSS THE 
YUCATAN PENINSULA AND THE NW CARIBBEAN IN SWLY FLOW AROUND AN 
UPPER RIDGE. MODERATE TO STRONG SUBSIDENCE ON THE EAST SIDE OF 
THE RIDGE IS KEEPING THE CENTRAL CARIBBEAN RELATIVELY CLOUD FREE 
WITH THE EXCEPTION OF CONVECTIVE ACTIVITY ASSOCIATED WITH THE 
TROPICAL WAVE. A SFC LOW OVER COLOMBIA IS GENERATING ISOLATED 
SHOWERS AND THUNDERSTORMS IN THE SW GULF ALONG THE COAST OF 
PANAMA. BUILDING HIGH PRESSURE IN THE W ATLC IS PRODUCING 
MODERATE TO STRONG EASTERLY WINDS ACROSS THE BASIN...WITH THE 
STRONGEST WINDS UP TO 30 KT ALONG THE COAST OF COLOMBIA.

ATLANTIC...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS HAVE MOVED INTO THE 
W ATLC AHEAD OF AN APPROACHING SHORTWAVE TROUGH CURRENTLY OVER 
THE EASTERN CONUS. A DEEP-LAYERED TROUGH OVER THE W ATLC EXTENDS 
A FRONTAL BOUNDARY TO JUST NORTH OF THE DISCUSSION 
AREA...HOWEVER...REMNANT ISOLATED SHOWERS AND THUNDERSTORMS 
REMAIN IN THE ATLC N OF 27N BETWEEN 66W-73W. A LARGE SFC RIDGE 
COVERS THE ENTIRE ATLC BASIN FROM AFRICA TO THE EASTERN GULF OF 
MEXICO. FAIR WEATHER STRATOCUMULUS CLOUDS CONTINUE TO FLOW 
AROUND THE RIDGE. AN E-W ELONGATED UPPER RIDGE OVER THE TROPICAL 
ATLANTIC CONTINUES TO ENHANCE CONVECTION ALONG THE ITCZ.

$$
WADDINGTON