000 AXNT20 KNHC 051805 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SAT DEC 05 2015 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1745 UTC. ...SPECIAL FEATURES... A STATIONARY FRONTAL BOUNDARY EXTENDS ACROSS THE SW NORTH ATLC FROM 30N67W W-SW TO THE STRAITS OF FLORIDA NEAR 24N80W TO NW HONDURAS NEAR 15N87W. NORTH OF THE AREA...STRONG HIGH PRESSURE ANCHORED OVER PENNSYLVANIA EXTENDING A RIDGE AXIS TO THE SE CONUS TIGHTENS THE GRADIENT THUS SUPPORTING NE TO E GALE-FORCE WINDS OVER FORECAST WATERS N OF FRONT BETWEEN 65W AND 78W. ASSOCIATED SEAS RANGE FROM 10 TO 13 FT. WINDS AND SEAS ARE FORECAST TO DIMINISH BY EARLY SUNDAY. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. FRESH TO STRONG TRADES ARE FROM 10.5N TO 16N BETWEEN 71W AND 80W ...EXCEPT NEAR GALE-FORCE WINDS WITHIN 90 NM OF THE COAST OF COLOMBIA WITH SEAS FROM 8 TO 11 FT. THE PRESSURE GRADIENT IN THE SW CARIBBEAN IS FORECAST TO INCREASE AS THE BROAD RIDGE OVER THE NE CONUS MOVES E TO ATLC WATERS. GALE-FORCE WINDS ARE FORECAST TO DEVELOP EARLY SUNDAY MORNING AND CONTINUE THROUGH THE AFTERNOON HOURS. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 04N05E AND CONTINUES TO 02N01E WHERE THE ITCZ BEGINS AND THEN EXTENDS ALONG 05N20W TO A 1013 MB LOW NEAR 04N24W TO 04N44W. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE FROM THE EQUATOR TO 07N BETWEEN THE PRIME MERIDIAN AND 27W. ...DISCUSSION... GULF OF MEXICO... BROAD MIDDLE LEVEL TROUGHING OVER THE SE CONUS WITH BASE EXTENDING SW TO CENTRAL GULF OF MEXICO IS SUPPORTING A STATIONARY FRONT EXTENDING FROM THE SW NORTH ATLC FROM 30N67W WSW TO THE STRAITS OF FLORIDA NEAR 24N80W TO NW HONDURAS NEAR 15N87W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING ACROSS THE FLORIDA STRAITS AND THE YUCATAN CHANNEL. OTHERWISE...THE REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1042 MB HIGH CENTERED OVER PENNSYLVANIA EXTENDING AN AXIS S-SW TO COASTAL TEXAS THEN SOUTHWARD TO A 1029 MB HIGH CENTERED NEAR TAMPICO MEXICO. DRY AIR SUBSIDENCE CONTINUE TO SUPPORT STABLE CONDITIONS. FRESH TO STRONG NE WINDS PREVAIL E OF 90W WHILE MODERATE TO GENTLE NE WINDS ARE W OF 90W. THIS OVERALL WIND REGIME IS EXPECTED TO PERSIST THROUGH EARLY SUNDAY. HOWEVER...ANOTHER RIDGE DEVELOPING OVER CENTRAL-SOUTHERN USA WILL TIGHTEN THE PRESSURE GRADIENT SUNDAY NIGHT...THUS SUPPORTING NNE FRESH TO STRONG WINDS. CARIBBEAN SEA... UPPER LEVEL RIDGING IS NOTED ON WATER VAPOR IMAGERY OVER THE WESTERN CARIBBEAN W OF 80W. UPPER LEVEL DIFFLUENCE ASSOCIATED WITH RIDGING ALOFT ALONG WITH THE TAIL OF A STATIONARY FRONT SUPPORTED BY TROUGHING IN THE MIDDLE LEVELS SUPPORT SCATTERED SHOWERS AND TSTMS ACROSS THE NW CARIBBEAN W OF 82W. A DIFFLUENT PATTERN ALOFT EXTENDS TO THE SW BASIN WHERE A SURFACE TROUGH IS ANALYZED FROM COASTAL NICARAGUA TO COASTAL CENTRAL PANAMA. SCATTERED SHOWERS AND TSTMS ARE W OF 80W. A MOIST AIRMASS IS MOVING ACROSS THE CENTRAL BASIN WHERE A MIDDLE LEVEL INVERTED TROUGH SUPPORT ISOLATED SHOWERS AND TSTMS...INCLUDING SOUTHERN DOMINICAN REPUBLIC AND ITS COASTAL WATERS. FRESH TO STRONG TRADES ARE FROM 10.5N TO 16N BETWEEN 71W AND 80W ...EXCEPT NEAR GALE-FORCE WINDS WITHIN 90 NM OF THE COAST OF COLOMBIA WITH SEAS FROM 8 TO 11 FT. THE PRESSURE GRADIENT IN THE SW CARIBBEAN IS FORECAST TO INCREASE AS A BROAD RIDGE OVER PENNSYLVANIA MOVES E TO ATLC WATERS. GALE-FORCE WINDS ARE FORECAST TO DEVELOP EARLY SUNDAY MORNING AND CONTINUE THROUGH THE AFTERNOON HOURS. SEE SPECIAL FEATURES FOR MORE INFORMATION. ...HISPANIOLA... A MOIST AIRMASS IS MOVING ACROSS THE CENTRAL CARIBBEAN WHERE A MIDDLE LEVEL INVERTED TROUGH SUPPORT ISOLATED SHOWERS AND TSTMS...INCLUDING SOUTHERN DOMINICAN REPUBLIC AND ITS COASTAL WATERS. SIMILAR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH LATE SUNDAY EXTENDING TO WESTERN HISPANIOLA AS THE MIDDLE LEVEL TROUGH AMPLIFIES...STRENGHTEN AND REMAIN NEARLY-STATIONARY. ATLANTIC OCEAN... BROAD MIDDLE LEVEL TROUGHING OVER THE SE CONUS WITH BASE EXTENDING SW TO CENTRAL GULF OF MEXICO IS SUPPORTING A WEAK STATIONARY FRONT EXTENDING FROM THE SW NORTH ATLC FROM 30N67W WSW TO THE STRAITS OF FLORIDA NEAR 24N80W TO NW HONDURAS NEAR 15N87W. NORTH OF THE AREA...STRONG HIGH PRESSURE ANCHORED OVER PENNSYLVANIA EXTENDING A RIDGE AXIS TO THE SE CONUS TIGHTENS THE GRADIENT THUS SUPPORTING NE TO E GALE-FORCE WINDS OVER FORECAST WATERS N OF FRONT BETWEEN 65W AND 78W. ASSOCIATED SEAS RANGE FROM 10 TO 13 FT. SEE SPECIAL FEATURES FOR MORE INFORMATION. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING GENERALLY WITHIN 60 NM EITHER SIDE OF THE FRONT. SURFACE RIDGING PREVAILS ACROSS THE CENTRAL ATLC. ACROSS THE EASTERN ATLC...A MIDDLE TO UPPER LEVEL LOW IS CENTERED NEAR 24N32W AND SUPPORTS A SURFACE TROUGH ALONG 27N29W TO 18N35W. HEAVY SHOWERS AND TSTMS ARE FROM 20N TO 24N BETWEEN 29W AND 33W. EXTENSIVE CLOUDINESS COVERS THE EASTERN ATLC FROM 17N-31N E OF 26W DUE TO DIFFLUENT SOUTHWESTERLY FLOW ALOFT. ISOLATED SHOWERS AND TSTMS ARE POSSIBLE ACROSS THIS AREA THROUGH LATE SATURDAY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ RAMOS