000 AXNT20 KNHC 180529 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST SUN NOV 18 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 0445 UTC. ...ITCZ/MONSOON TROUGH... MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 10N14W TO 6N20W WHERE THE ITCZ AXIS CONTINUES ALONG 5N26W TO 7N35W THEN RESUMES NEAR 10N44W ALONG 8N51W TO SOUTH AMERICA NEAR 8N59W. A SURFACE TROUGH IS ALONG THE E SIDE OF AN UPPER TROUGH FROM 20N33W ALONG 17N38W TO 12N41W WITH SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS WITHIN 240 NM EITHER SIDE OF THE TROUGH AXIS. SCATTERED MODERATE/STRONG CONVECTION IS INLAND AND WITHIN 60 NM ALONG THE COAST OF LIBERIA AND SIERRA LEONE BETWEEN 9W-12W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 8N-10N BETWEEN 27W-31W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER TROUGH EXTENDS FROM THE GREAT LAKES OVER THE E CONUS INTO THE E GULF OF MEXICO E OF 93W CONTINUING S INTO THE NW CARIBBEAN. A BROAD UPPER RIDGE ANCHORED OVER THE E PACIFIC REGION COVERS THE REMAINDER OF THE W GULF. A SURFACE RIDGE DOMINATES THE GULF EXTENDING FROM THE NEW ENGLAND. A SURFACE TROUGH REMAINS ALONG THE COAST OF MEXICO FROM 23N97W ALONG 21N96W TO 19N94W AND IS GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 120 NM ALONG THE COAST S OF 25N W OF 93W. A SECOND SURFACE TROUGH IS IN THE SE GULF EXTENDING FROM THE STRAITS OF FLORIDA NEAR 24N81W TO 22N87W WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 60 NM EITHER SIDE OF THE TROUGH AXIS. THE REMAINDER OF THE GULF IS UNDER FAIR WEATHER AGAIN TONIGHT. SURFACE RIDGE WILL WEAKEN MON AND TUE. A TIGHT PRESSURE GRADIENT BETWEEN THE RIDGE AND BROAD TROUGHING OVER THE W ATLC WILL MAINTAIN FRESH NE WINDS OVER THE NE GULF THROUGH MUCH OF TODAY. THE PRESSURE GRADIENT WILL INCREASE IN THE E GULF AGAIN WED INTO THU AS A HIGH DEVELOPS OVER THE LOWER MISSISSIPPI VALLEY. CARIBBEAN SEA... A WEAK PRESSURE PATTERN REMAINS ACROSS THE CARIBBEAN TONIGHT. THE BROAD UPPER TROUGH OVER THE E GULF OF MEXICO EXTENDS OVER THE NW CARIBBEAN TO CENTRAL AMERICA W OF 77W WHILE AN UPPER RIDGE DOMINATES THE REMAINDER OF THE CARIBBEAN. THE UPPER RIDGE EXTENDS FROM AN UPPER HIGH OVER VENEZUELA WITH THE AXIS EXTENDING OVER THE LESSER ANTILLES CONTINUING OVER THE CENTRAL ATLC. THE MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 10N74W INTO THE SW CARIBBEAN ALONG 11N78W ACROSS COSTA RICA INTO THE E PACIFIC REGION. CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 14N BETWEEN 71W-78W AND S OF 12N W OF 80W. THE UPPER RIDGE IS PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ACROSS THE CENTRAL CARIBBEAN WITHIN 150 NM OF LINE FROM 14N75W ACROSS HISPANIOLA TO NEAR 20N71W. THIS IS LEAVING THE NW AND E CARIBBEAN WITH FAIR WEATHER AGAIN TONIGHT. A WEAK PRESSURE PATTERN WILL MAINTAIN GENERALLY MODERATE TRADE WINDS ACROSS THE AREA THROUGH TUE INCREASING IN THE NW CARIBBEAN WED AND THU. NE SWELLS IN THE TROPICAL N ATLC WATERS E OF THE LEEWARD ISLANDS WILL SUBSIDE THROUGH SUN NIGHT. LOWER PRESSURE IN THE FAR SW CARIBBEAN IN COMBINATION WITH AN UPPER TROUGH WILL MAINTAIN UNSETTLED WEATHER OVER MUCH OF THE SW AND CENTRAL CARIBBEAN THROUGH TUE. ATLANTIC OCEAN... THE BROAD UPPER TROUGH IN THE GULF OF MEXICO COVERS THE FAR W ATLC W OF 70W SUPPORTING A WEAK STATIONARY FRONT THAT EXTENDS THROUGH 32N73W ALONG 31N74W 32N77W THEN S TO 27N79W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF THE FRONT E OF 77W AND N OF 28N W OF 80W. THE BROAD UPPER RIDGE OVER THE CARIBBEAN EXTENDS OVER THE W/CENTRAL ATLC ACROSS THE LEEWARD ISLANDS NEAR 17N62W TO BEYOND 32N53W. A SURFACE TROUGH IS BENEATH THE UPPER RIDGE EXTENDING THROUGH 32N62W ALONG 29N65W TO 23N68W. THE SURFACE TROUGH COUPLED WITH THE UPPER RIDGE THAT IS PROVIDING DIFFLUENCE ALOFT ARE GENERATING CLUSTERS OF SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS WITHIN 150 NM OF LINE FROM HISPANIOLA NEAR 20N71W TO 25N68W AND WITHIN 225 NM EITHER SIDE OF THE REMAINDER OF THE SURFACE TROUGH. THE UPPER TROUGH IN THE E/CENTRAL ATLC HAS BECOME CUTOFF. THE UPPER LOW IS CENTERED NEAR 21N41W WITH THE UPPER TROUGH EXTENDING S INTO THE TROPICS TO NEAR 10N50W AND IS ALSO ENHANCING THE ACTIVITY ASSOCIATED WITH THE SURFACE TROUGH IN THE ITCZ/MONSOON TROUGH SECTION ABOVE. A LARGE SURFACE RIDGE DOMINATES THE ATLC BETWEEN 10W-60W AND IS ANCHORED BY A 1027 MB HIGH NEAR 33N39W. W ATLC STATIONARY FRONT WILL REMAIN THROUGH TUE WITH A GRADUALLY WEAKENING SURFACE RIDGE BEHIND IT OVER THE SE CONUS. A BROAD AREA OF LOW PRESSURE IS FORECAST TO DEVELOP SUN AND MON OVER W/CENTRAL ATLC N OF 25N AND LIFT N OF THE AREA LATE MON INTO TUE. A COLD FRONT WILL MOVE INTO NW WATERS WED AND REACH FROM 32N64W THROUGH THE CENTRAL BAHAMAS THU. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW