000 AXNT20 KNHC 250534 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED APR 25 2012 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE E TROPICAL ATLC NEAR 7N13W TO 4N19W WHERE THE ITCZ CONTINUES ALONG 1N29W TO 1N 40W THEN S OF THE EQUATOR NEAR 47W. SCATTERED MODERATE/ ISOLATED STRONG CONVECTION IS FROM 3N-4N BETWEEN 27W-30W. SMALL CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 45 NM OF LINE FROM 5N16W TO THE COAST OF LIBERIA NEAR 6N10W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER TROUGH REMAINS OVER THE GULF INTO THE W ATLC WITH ANY ASSOCIATED SURFACE FEATURES IN THE W ATLC. A SURFACE RIDGE DOMINATES THE GULF ANCHORED BY A 1019 MB HIGH NEAR 26N89W. STRONG SUBSIDENCE AND DRY STABLE AIR ALSO DOMINATE THE GULF WITH CLEAR SKIES AND COOLER TEMPERATURES ACROSS THE ENTIRE BASIN. THE HIGH WILL MOVE E TO THE W ATLC BY LATE WED WITH A RIDGE EXTENDING W TO THE TEXAS COAST THROUGH SAT. SOUTHERLY RETURN FLOW WILL DEVELOP OVER THE FAR W GULF BEGINNING TONIGHT SPREADING E ACROSS MUCH OF THE AREA BY FRI WITH LITTLE CHANGE INTO SAT. A WEAK COLD FRONT WILL SAG TOWARD N GULF COAST SUN. CARIBBEAN SEA... THE UPPER TROUGH OVER THE GULF OF MEXICO AND W ATLC DIPS S OVER THE FAR NW CARIBBEAN. A SURFACE TROUGH EXTENDING FROM A STATIONARY FRONT IN THE W/CENTRAL ATLC AS IT CROSSES HISPANIOLA NEAR 19N70W CONTINUING ALONG 14N73W TO INLAND OVER COLOMBIA NEAR 11N73W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ACROSS THE CENTRAL CARIBBEAN WITHIN 120 NM W AND 75 NM E OF THE TROUGH. BROAD UPPER RIDGE DOMINATES THE REMAINDER OF THE CARIBBEAN BASIN ANCHORED OVER CENTRAL VENEZUELA. THE CONVERGENCE OF UPPER AND LOWER LEVEL FLOW IS GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS S OF 12N TO INLAND OVER PANAMA AND COSTA RICA. SURFACE TROUGH WILL DRIFT W AND DISSIPATE WED. HIGH PRESSURE WILL MOVE FROM GULF OF MEXICO INTO THE W ATLC LATE WED ALLOWING WINDS TO INCREASE FROM E OF THE WINDWARD ISLANDS THROUGH THE CENTRAL CARIBBEAN THROUGH SUN. ATLANTIC OCEAN... THE BROAD UPPER TROUGH OVER THE GULF OF MEXICO EXTENDS INTO THE W ATLC SUPPORTING A STATIONARY FRONT THAT ENTERS THE W/CENTRAL ATLC NEAR 32N62W EXTENDING TO 26N65W TO OVER HISPANIOLA NEAR 19N70W WHERE IT BECOMES A SURFACE TROUGH INTO THE CARIBBEAN. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 150/200 NM E OF THE FRONT. A SURFACE TROUGH AS DENOTED BY A WIND SHIFT IS TO THE W OF THE FRONT EXTENDING FROM 29N71W 24N73W ACROSS THE BAHAMA ISLANDS TO THE COAST OF CUBA NEAR 21N77W. STRONG SUBSIDENCE AND DRY STABLE AIR ARE W OF THE FRONT THUS LIMITING ANY SHOWER ACTIVITY ASSOCIATED WITH THE SURFACE TROUGH. THE UPPER RIDGE OVER THE CARIBBEAN EXTENDS A RIDGE AXIS ACROSS THE VIRGIN ISLANDS TO BEYOND 32N58W FURTHER ENHANCING THE ACTIVITY ASSOCIATED WITH THE FRONT. AN UPPER LOW IS IN THE E/CENTRAL ATLC CENTERED NEAR 27N45W EXTENDING AN UPPER TROUGH S INTO THE TROPICS TO NEAR 11N37W SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 31N48W ALONG 26N46W TO 21N47W WITH SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS FROM 23N-28N E OF THE TROUGH AXIS TO 40W. A BROAD SURFACE RIDGE DOMINATES THE ATLC W OF 60W WITH A WEAKNESS IN THE IMMEDIATE VICINITY OF THE ABOVE SURFACE TROUGH AND ANCHORED NE OF THE CANADIAN MARITIMES GIVING THE REMAINDER OF THE ATLC FAIR WEATHER TONIGHT. STATIONARY FRONT WILL MOVE SLOWLY E AND DISSIPATE THROUGH EARLY FRI. SURFACE RIDGE OVER THE N GULF OF MEXICO WILL SHIFT E TO S OF BERMUDA THROUGH THE N CENTRAL ATLANTIC WITH A RIDGE EXTENDING ALONG 28N. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW