000 AXNT20 KNHC 121126 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST SAT DEC 12 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...SPECIAL FEATURE... A 1000 MB SURFACE LOW IS LOCATED ACROSS THE CENTRAL ATLANTIC NEAR 33N50W. A COLD FRONT EXTENDS SW FROM THE LOW TO 27N54W TO 26N64W. THE FRONT THEN BECOMES STATIONARY TO 26N74W. STRONG TO GALE FORCE WINDS ARE NOTED IN SCATTEROMETER DATA SW OF THE LOW AND BEHIND THE COLD FRONT N OF 29N BETWEEN 47W-54W...WITH SEAS RANGING FROM 14-20 FT. EXPECT THESE CONDITIONS TO PREVAIL OVER THE NEXT 18 HOURS. FOR MORE DETAILS PLEASE REFER TO THE HIGH SEAS FORECAST PRODUCT UNDER THE AWIPS/WMO HEADERS MIAHSFAT2/FZNT02. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA NEAR 10N14W TO 08N17W. THE ITCZ BEGINS FROM 08N17W TO 02N31W TO 02N47W. SCATTERED MODERATE CONVECTION PREVAILS FROM 00N-08N AND E OF 35W. ...DISCUSSION... GULF OF MEXICO... AN UPPER-LEVEL RIDGE EXTENDS FROM THE E PACIFIC ACROSS MEXICO AND THE W GULF TO OVER THE SE CONUS SUPPORTING A SURFACE RIDGE THAT DOMINATES THE GULF. TO THE E...AN UPPER-LEVEL TROUGH OVER THE W ATLANTIC CLIPS THE STRAITS OF FLORIDA NEAR 23N78W THEN EXTENDS ACROSS CENTRAL CUBA INTO THE NW CARIBBEAN. WITH THESE FEATURES...A STRONG SUBSIDENCE AND A DRY AIRMASS COVERS THE GULF SUPPORTING FAIR WEATHER ACROSS THE AREA. SCATTEROMETER DATA DEPICTS A GENTLE TO MODERATE ANTICYCLONIC FLOW ACROSS THE BASIN. EXPECT OVER THE NEXT 24-48 HOURS FOR A PRESSURE GRADIENT TO TIGHTEN ACROSS THE BASIN AS A DEEPENING LOW PRESSURE WITH ITS ASSOCIATED COLD FRONT APPROACHES THE NW GULF. CARIBBEAN SEA... AN UPPER-LEVEL TROUGH EXTENDS FROM THE W ATLANTIC ACROSS THE STRAITS OF FLORIDA AND CENTRAL CUBA FROM 23N78W TO 16N80W. ISOLATED CONVECTION PREVAILS E OF THIS UPPER TROUGH ALONG A LINE FROM 15N84W TO 19N76W. TO THE E...A DIFFLUENT FLOW ALOFT CONTINUES TO ENHANCE CLOUDINESS AND CONVECTION ACROSS HISPANIOLA AND ADJACENT WATERS MAINLY N OF 18N BETWEEN 69W-73W. SHALLOW MOISTURE IS TRANSPORTED BY THE MODERATE TO FRESH TRADES ENHANCING ISOLATED CONVECTION ACROSS THE REMAINDER OF THE BASIN. EXPECT A SIMILAR WEATHER REGIME TO PREVAIL OVER THE NEXT 24 HOURS. ...HISPANIOLA... A SURFACE TROUGH WAS ANALYZED ACROSS NW HISPANIOLA AND THE SW ATLANTIC FROM 23N70W TO 20N73W. A DIFFLUENT FLOW ALOFT SUPPORTS THIS TROUGH AND ENHANCES CLOUDINESS AND CONVECTION ACROSS THE ISLAND MAINLY BETWEEN 69W-73W. THE UPPER-LEVEL TROUGH IS EXPECTED TO MOVE E AND DEVELOP A LOW N OF THE ISLAND IN 24 HOURS. THIS WILL KEEP MOISTURE HIGH THROUGH THE WEEKEND ACROSS THE ISLAND AND CONVECTION WILL BE POSSIBLE. ATLANTIC OCEAN... AN UPPER-LEVEL TROUGH EXTENDS ACROSS THE W ATLANTIC AND THE NW CARIBBEAN. AT THE SURFACE...A TROUGH WAS ANALYZED FROM 29N73W TO 25N76W. TO THE E OF THE SURFACE TROUGH...A DIFFLUENT FLOW ALOFT SUPPORTS SCATTERED LIGHT TO MODERATE CONVECTION BETWEEN 63W-73W. A FRONTAL SYSTEM EXTENDS ACROSS THE W-CENTRAL ATLANTIC. IT BEGINS AS A STATIONARY FRONT FROM 26N73W TO 26N64W. THE FRONT TRANSITIONS TO A COLD FRONT FROM 26N64W TO 27N56W TO 31N49W. ISOLATED MODERATE CONVECTION IS OBSERVED WITHIN 100 NM OF THE FRONT BETWEEN 48W-55W. A GALE WARNING IS IN EFFECT FOR THE AREA BEHIND THE FRONT. PLEASE REFER TO THE SPECIAL FEATURES SECTION ABOVE FOR DETAILS. A SURFACE RIDGE PREVAILS ACROSS THE CENTRAL AND E ATLANTIC ANCHORED BY A 1021 MB HIGH NEAR 25N43W AND ANOTHER 1021 MB HIGH NEAR 24N33W. N OF THIS RIDGE...A COLD FRONT ENTERS THE AREA FROM 27N37W TO 31N29W. EXPECT OVER THE NEXT 24 HOURS FOR THE COLD FRONT ACROSS THE W-CENTRAL ATLANTIC TO CONTINUE MOVING E WITH CONVECTION. THE COLD FRONT ACROSS THE E- CENTRAL ATLANTIC IS EXPECTED TO WEAKEN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ ERA