000
AXNT20 KNHC 062347
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
805 PM EDT WED APR 06 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION 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 
2300 UTC.

...ITCZ...

ITCZ AXIS EXTENDS FROM THE BORDER BETWEEN LIBERIA AND SIERRA 
LEONE NEAR 8N11W ALONG 3N20W 1N30W CROSSING THE EQUATOR NEAR 39W 
INTO NE BRAZIL NEAR 2S45W. ISOLATED MODERATE/STRONG CONVECTION 
IS FROM 4N-5N BETWEEN 17W-19W...FROM 1N-2N BETWEEN 33W-36W...AND 
FROM EQ-3N BETWEEN 39W-50W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY CONTINUES TO SHOW A SHORTWAVE MIDDLE-UPPER 
LEVEL TROUGH OVER THE S CENTRAL GULF WHICH SUPPORTS A WEAK 1016 
MB SURFACE LOW N OF THE YUCATAN PENINSULA NEAR 23N90W. AS OF 
2100 UTC...A WARM FRONT EXTENDS EWD FROM THE LOW TO 
24N85W...AND A DISSIPATING STATIONARY FRONT EXTENDS SW ALONG 
22N91W 19N92W. LOW-MID LEVEL CLOUDS ARE N OF THE WARM FRONT 
ALONG WITH ISOLATED SHOWERS EVIDENT IN TRMM SATELLITE RAINFALL 
DATA. LOW-LEVEL CLOUDS AND POSSIBLE ISOLATED SHOWERS ARE ALSO W 
OF THE DISSIPATING STATIONARY BOUNDARY. THE REMAINDER OF THE 
BASIN IS EXPERIENCING MOSTLY FAIR CONDITIONS UNDER THE INFLUENCE 
OF DRY AIR ALOFT...AND SURFACE RIDGING TO THE NE CENTERED OFF 
THE COAST OF SOUTH CAROLINA. THE LOW IS EXPECTED TO DISSIPATE 
OVER THE NEXT 24 HOURS AS THE FRONT CONTINUES TO WEAKEN ALLOWING 
SURFACE RIDGING TO BUILD IN ACROSS THE BASIN. S-SE RETURN FLOW 
IS EXPECTED TO INCREASE IN THE FAR W GULF ALONG THE COAST OF 
TEXAS. 

CARIBBEAN SEA...
THE CARIBBEAN REMAINS UNDER MOSTLY SWLY FLOW ALOFT AROUND AN 
UPPER LEVEL RIDGE CENTERED N OF VENEZUELA. MOISTURE FROM THE E 
PACIFIC IS STREAMING ACROSS THE WRN HALF OF THE BASIN IN THIS 
SWLY FLOW SUPPORTING A FEW HIGH CLOUDS. THE ERN HALF OF THE 
BASIN IS UNDER DRY AND SUBSIDENT AIR SUPPORTING CLEARER SKIES. 
PATCHES OF SHOWERS/ISOLATED THUNDERSTORMS ARE NOTED ACROSS THE 
NRN CARIBBEAN ISLANDS INCLUDING CUBA...HISPANIOLA...PUERTO 
RICO...AND JAMAICA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE 
ALSO NOTED OVER AND N OF COSTA RICA AND PANAMA. TOTAL 
PRECIPITABLE WATER IMAGERY ALSO INDICATES AN AREA OF ENHANCED 
MOISTURE OVER THE FAR SW CARIBBEAN WHICH MAY BE ENHANCING SOME 
OF THESE SHOWERS. FRESH TO STRONG SURFACE WINDS ARE NOTED ACROSS 
MUCH OF THE BASIN AND ARE FORECAST TO PERSIST AS HIGH PRESSURE 
BUILDS TO THE N ACROSS THE W ATLC. 

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH CONTINUES TO PUSH EWD ACROSS THE W ATLC 
TOWARDS THE CENTRAL ATLC SUPPORTING A COLD FRONT THAT ENTERS THE 
DISCUSSION AREA NEAR 32N61W TO THE CENTRAL BAHAMAS NEAR 
24N75W...AS OF 2100 UTC...CONTINUING AS A DISSIPATING STATIONARY 
FRONT INTO THE FLORIDA STRAITS. SCATTERED SHOWERS/THUNDERSTORMS 
ARE WITHIN 75 NM AHEAD OF THE FRONT...GRADUALLY DISSIPATING 
CLOSER TO THE BAHAMAS. CLEAR SKIES AND FAIR WEATHER ARE IN THE 
WAKE OF THE FRONT AS A 1025 MB HIGH BUILDS OFF THE COAST OF 
SOUTH CAROLINA. FARTHER E...A SURFACE RIDGE DOMINATES THE 
CENTRAL ATLC ANCHORED BY A 1027 MB HIGH NEAR 39N42W SUPPORTED BY 
AN UPPER LEVEL RIDGE EXTENDING FROM THE ERN CARIBBEAN TO NEAR 
31N51W THEN CONTINUING UP 45W. A NARROW UPPER LEVEL TROUGH ALONG 
28N COVERS THE FAR E ATLC SUPPORTING A 1008 MB LOW SE OF THE 
AZORES ISLANDS. A COLD FRONT EXTENDS FROM THE LOW CENTER INTO 
THE DISCUSSION AREA NEAR 32N23W ALONG 27N25W 22N34W CONTINUING 
AS A SHEAR AXIS INTO THE SURFACE RIDGE TO NEAR 18N51W. SCATTERED 
SHOWERS/POSSIBLE THUNDERSTORMS ARE WITHIN 60 NM EITHER SIDE OF 
THE COLD FRONT. ISOLATED SHOWER ARE WITHIN 30 NM EITHER SIDE OF 
THE SHEAR AXIS. 

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
WALTON