000 AXNT20 KNHC 192345 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SAT DEC 19 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...SPECIAL FEATURE... A PRESSURE GRADIENT BETWEEN THE HIGH PRESSURE CURRENTLY OVER THE ATLANTIC AND LOWER PRESSURES OVER SOUTH AMERICA WILL INTENSIFY THIS EVENING SUPPORTING GALE FORCE WINDS ACROSS THE S-CENTRAL CARIBBEAN FROM 11N-13N BETWEEN 72W-77W. THESE CONDITIONS ARE EXPECTED TO CONTINUE THROUGH SUNDAY AFTERNOON. FOR MORE INFORMATION PLEASE REFER TO THE HIGH SEAS FORECAST PRODUCT UNDER AWIPS/WMO HEADER MIAHSFAT2/FZNT02 KNHC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 04N08W TO 04N13W. THE ITCZ EXTENDS FROM 04N13W TO 04N30W TO 04N46W...THEN RESUMES E OF A SURFACE TROUGH FROM 03N49W TO THE NORTHERN COAST OF SOUTH AMERICA NEAR 03N52W. THE SURFACE TROUGH PREVIOUSLY MENTIONED EXTENDS FROM 06N47W TO 01N47W. SCATTERED LIGHT TO MODERATE CONVECTION PREVAILS IN THE VICINITY OF THE SURFACE TROUGH FROM 01N-05W BETWEEN 40W-51W. ...DISCUSSION... GULF OF MEXICO... A SURFACE RIDGE IS BUILDING ACROSS THE BASIN IN THE WAKE OF A FRONTAL SYSTEM CURRENTLY EXTENDING FROM THE YUCATAN PENINSULA TO W CUBA. THE RIDGE IS ANCHORED BY A 1028 MB HIGH LOCATED NEAR 22N98W AND A 1035 MB HIGH NEAR 32N88W. CLOUDINESS AND ISOLATED CONVECTION IS OBSERVED ACROSS THE SE GULF FROM THE YUCATAN CHANNEL TO THE FLORIDA STRAITS BEHIND THE FRONT. SCATTEROMETER DATA DEPICTS GENTLE TO MODERATE EASTERLY FLOW ACROSS THE W GULF MAINLY W OF 92W WHILE MODERATE TO FRESH NORTHERLY FLOW PREVAILS E OF 92W. OVER THE NEXT 24 HOURS...EXPECT FOR CONVECTION TO CONTINUE ACROSS THE SE PORTION OF THE BASIN. CARIBBEAN SEA... A FRONTAL SYSTEM EXTENDS ACROSS THE W CARIBBEAN. IT BEGINS AS A STATIONARY FRONT OVER THE YUCATAN PENINSULA...THEN BECOMES A COLD FRONT FROM 21N87W TO 22N82W. SCATTERED MODERATE CONVECTION IS OBSERVED E OF THE STATIONARY FRONT FROM 16N-20N AND W OF 84W. ANOTHER AREA OF SCATTERED MODERATE CONVECTION IS LOCATED S OF 11N BETWEEN 80W-83W. AN UPPER-LEVEL LOW CONTINUES OVER HISPANIOLA SUPPORTING CLOUDINESS AND ISOLATED CONVECTION ACROSS THE ISLAND AND ADJACENT WATERS. A GALE WARNING IS IN EFFECT FOR THE SOUTHERN CARIBBEAN. PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR DETAILS. SCATTEROMETER DATA DEPICTS MODERATE TO FRESH TRADES ACROSS THE BASIN EXCEPT FRESH TO STRONG WINDS BETWEEN 71W-79W. EXPECT OVER THE NEXT 24 HOURS FOR THE FRONTAL SYSTEM TO WEAKEN ACROSS THE W CARIBBEAN. CONVECTION IS STILL POSSIBLE ACROSS THIS AREA. THE UPPER-LEVEL LOW OVER HISPANIOLA WILL MOVE E SUPPORTING CONVECTION ACROSS PUERTO RICO. ...HISPANIOLA... ISOLATED CONVECTION CONTINUES ACROSS THE ISLAND SUPPORTED BY AN UPPER-LEVEL LOW CENTERED NEAR 20N71W. THIS LOW IS EXPECTED TO MOVE E AWAY FROM THE ISLAND OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... THE COLD FRONT THAT EXTENDS ACROSS THE W CARIBBEAN IS ALSO OVER THE W ATLANTIC FROM 23N80W TO 31N66W. ISOLATED CONVECTION IS OBSERVED WITHIN 100 NM OF THE FRONT AFFECTING PORTIONS OF THE FLORIDA STRAITS AND BAHAMAS. TO THE E...A BROAD 1031 MB SURFACE HIGH IS CENTERED NEAR 32N40W. S OF THIS HIGH...A COLD FRONT EXTENDS FROM 23N53W TO 23N33W TO 31N16W. ISOLATED CONVECTION IS OBSERVED ALONG THIS BOUNDARY. A SURFACE TROUGH WAS ANALYZED OVERT THE FAR E ATLANTIC EXTENDING FROM 25N18W TO 29N17W. OVER THE NEXT 24 HOURS...THE COLD FRONTS WILL CONTINUE MOVING E WITH CONVECTION. HIGH PRESSURE WILL PREVAIL ACROSS THE CENTRAL ATLANTIC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ ERA