000 AXNT20 KNHC 122352 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURE... ...GALE WARNING IN W ATLC...A DEVELOPING STORM CENTER IS ALONG THE N PERIPHERY OF THE DISCUSSION AREA WITH A 1000 MB LOW NEAR 32N45W WITH A COLD FRONT EXTENDING INTO THE AREA FROM A TRIPLE POINT NEAR 32N42W ALONG 26N51W TO 25N59W WHERE IT BECOMES STATIONARY TO 22N70W. GALE FORCE WINDS WILL PRECEDE AND TRAIL THE FRONT N OF 29N BETWEEN 42W-48W THROUGH 13/0000 UTC. FOR MORE DETAILS PLEASE SEE THE HIGH SEAS FORECAST UNDER THE AWIPS/WMO HEADERS MIAHSFAT2/FZNT02. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE E TROPICAL ATLC NEAR 7N11W TO 5N16W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 4N21W 4N36W ACROSS THE EQUATOR AND INTO SOUTH AMERICA NEAR 50W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 45 NM OF LINE FROM 6N30W TO 7N33W. ...DISCUSSION... GULF OF MEXICO... SHARP UPPER RIDGE EXTENDS FROM THE E PACIFIC ACROSS MEXICO AND THE GULF TO OVER THE E CONUS NEAR THE MISSISSIPPI DELTA. A BROAD SURFACE RIDGE DOMINATES THE GULF EXTENDING FROM A PAIR OF 1024 MB HIGHS IN THE W ATLC. THE UPPER RIDGE IS ADVECTING UPPER LEVEL MOISTURE ACROSS THE W GULF AND COUPLED WITH THE S TO SE RETURN FLOW AROUND THE SURFACE RIDGE IS GENERATING SCATTERED SHOWERS W OF 93W AND SOME ISOLATED SHOWERS N OF 28N BETWEEN 85W-88W. STRONG SUBSIDENCE AND DRY STABLE AIR COVER THE GULF E OF 90W GIVING THE REMAINDER OF THE GULF FAIR WEATHER THIS EVENING. FRESH TO STRONG WINDS ARE EXPECTED W OF 90W TONIGHT AHEAD OF A COLD FRONT THAT IS EXPECTED TO ENTER THE NW GULF SUN MORNING. FRONT WILL EXTEND FROM S LOUISIANA TO VERACRUZ MEXICO SUN NIGHT AND BECOME STATIONARY FROM FLORIDA PANHANDLE TO BAY OF CAMPECHE MON. CARIBBEAN SEA... AN UPPER LOW IS OVER THE BAHAMA ISLANDS EXTENDING AN UPPER TROUGH ACROSS E CUBA OVER THE NW CARIBBEAN TO NEAR 13N84W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 17N BETWEEN 70W-76W INCLUDING HISPANIOLA AND E CUBA. STRONG SUBSIDENCE AND DRY STABLE AIR COVERS THE REMAINDER OF THE CARIBBEAN GIVING THE REMAINDER OF THE BASIN FAIR WEATHER THIS EVENING. LITTLE CHANGE IS EXPECTED THROUGH THE WEEKEND. ...HISPANIOLA... THE UPPER TROUGH OVER THE CARIBBEAN IS GIVING THE ISLAND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS. THE UPPER LOW/TROUGH WILL REMAIN E OF THE ISLAND THROUGH MON. THIS WILL KEEP MOISTURE HIGH THROUGH THE MON BRINGING SHOWERS AND POSSIBLE THUNDERSTORMS TO THE ISLAND. ATLANTIC OCEAN... THE SURFACE RIDGE IS ANCHORED OFF THE COAST OF THE CAROLINAS AND EXTENDS A RIDGE AXIS SW TO OVER THE GULF OF MEXICO. A NEWLY DEVELOPED UPPER LOW IS OVER THE CENTRAL BAHAMAS NEAR 23N75W EXTENDING AN UPPER TROUGH S-SW INTO THE CARIBBEAN AND IS SUPPORTING A SURFACE TROUGH THAT EXTENDS ALONG 73W FROM 21N-26N. THE UPPER TROUGH IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 24N TO OVER HISPANIOLA BETWEEN 68W-71W. A BROAD UPPER RIDGE TO THE E OF THE UPPER TROUGH IS PROVIDING DIFFLUNCE ALOFT TO GENERATE SCATTERED TO NUMEROUS SHOWERS WITHIN 200 NM OF LINE FROM 28N57W TO 23N73W WHICH ENCOMPASSES THE FRONT IN THE SPECIAL FEATURES AND THE SURFACE TROUGH ABOVE. THE REMAINDER OF THE CENTRAL ATLC AND E ATLC ARE DOMINATED BY A SURFACE RIDGE THAT EXTENDS ACROSS THE CANARY ISLANDS ALONG 25N25W TO A 1018 MB HIGH NEAR 23N38W. THE W ATLC SURFACE TROUGH WILL DRIFT W THROUGH SUN NIGHT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW