000 AXNT20 KNHC 251031 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE E TROPICAL ATLC NEAR 12N16W TO 7N18W WHERE THE ITCZ CONTINUES ALONG 3N24W ALONG 1N36W TO 1N47W THEN S OF THE EQUATOR AND INTO SOUTH AMERICA NEAR 50W. SMALL CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 4N TO THE EQUATOR BETWEEN 26W-35W. SCATTERED THUNDERSTORMS ARE IN THE TROPICAL WATERS FROM 2N-7N BETWEEN 4W-15W. ...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 27N87W. STRONG SUBSIDENCE AND DRY STABLE AIR ALSO DOMINATE THE GULF WITH CLEAR SKIES ACROSS THE ENTIRE BASIN. THE HIGH WILL MOVE ENE TO THE W ATLC THIS AFTERNOON 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 EXTENDS S FROM THE COAST OF HISPANIOLA NEAR 18N72W CONTINUING ALONG 15N74W TO OFF THE COAST OF COLOMBIA NEAR 12N75W GENERATING SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS ACROSS THE CENTRAL CARIBBEAN WITHIN 150 NM E OF THE TROUGH WITH ISOLATED SHOWERS WITHIN 120 NM W OF THE TROUGH. BROAD UPPER RIDGE DOMINATES THE REMAINDER OF THE CARIBBEAN BASIN ANCHORED OVER VENEZUELA. THE CONVERGENCE OF UPPER AND LOWER LEVEL FLOW IS GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS INLAND AND WITHIN 90 NM ALONG THE COAST FROM 80W IN PANAMA TO 12N IN NICARAGUA. THE SURFACE TROUGH WILL MOVE W AND EXTEND FROM THE WINDWARD PASSAGE TO THE SW CARIBBEAN BY LATE TONIGHT THEN FROM E CUBA TO THE SW CARIBBEAN BY THU NIGHT AND THEN BEGIN TO WEAKEN AS IT REACHES FROM CENTRAL CUBA TO OFF THE COAST OF COSTA RICA FRI. 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. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 150/200 NM E OF THE FRONT WITHIN ISOLATED SHOWERS WITHIN 120 NM W OF THE FRONT S OF 27W. A SURFACE TROUGH IS TO THE W OF THE FRONT EXTENDING FROM 31N68W ALONG 27N70W TO 24N73W. STRONG SUBSIDENCE AND DRY STABLE AIR ARE W OF THE FRONT THUS LIMITING ANY SHOWER ACTIVITY TO ISOLATED SHOWERS IMMEDIATELY ALONG THE TROUGH AXIS. THE UPPER RIDGE OVER THE CARIBBEAN EXTENDS A RIDGE AXIS ACROSS THE VIRGIN/LEEWARD ISLANDS TO BEYOND 32N56W FURTHER ENHANCING THE ACTIVITY ASSOCIATED WITH THE FRONT. AN UPPER LOW IS IN THE E/CENTRAL ATLC CENTERED NEAR 26N42W EXTENDING AN UPPER TROUGH S INTO THE TROPICS TO NEAR 14N31W AND SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 31N49W ALONG 26N46W TO 20N45W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 22N-28N E OF THE TROUGH AXIS TO 37W. 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 THIS MORNING. THE STATIONARY FRONT WILL GRADUALLY DISSIPATE THROUGH EARLY FRI. THE S PORTION WILL WEAKEN TO A TROUGH THAT MOVES BACK W FROM THE SE BAHAMAS TO E CUBA THU FROM CENTRAL BAHAMAS TO CENTRAL CUBA FRI AND FROM THE W BAHAMAS TO W CUBA SAT AND SUN. HIGH PRESSURE OVER THE E GULF OF MEXICO WILL SHIFT E TO THE FAR W ATLC TODAY AND TO THE FAR NE PORTION BY LATE TONIGHT. BY THU A RIDGE WILL EXTEND FROM NEAR BERMUDA TO CENTRAL FLORIDA. THE RIDGE WILL THEN SHIFT N TO 29N SAT AND TO 30N SUN. A TIGHTENING PRESSURE GRADIENT BETWEEN THE RIDGE AND TROUGH WILL ALLOW FOR INCREASING WINDS OVER THE SOUTHERN PORTION THROUGH THE PERIOD. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW