000 AXNT20 KNHC 182350 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST WED NOV 18 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. ...TROPICAL WAVES... A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL ATLANTIC WITH AXIS EXTENDING FROM 14N54W TO 07N54W...MOVING W AT ABOUT 15 TO 20 KT WITHIN THE LAST 24 HOURS. SSMI TPW IMAGERY DEPICTS MODERATE TO HIGH MOISTURE IN THE ENVIRONMENT OF THE WAVE MAINLY S OF 11N. ISOLATED MODERATE CONVECTION IS OBSERVED ALONG THE WAVE AXIS...WITH A HIGHER CONCENTRATION AT ABOUT 180 NM E FROM THE AXIS. A TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN WITH AXIS EXTENDING FROM 18N69W TO 12N69W...MOVING W AT 15 TO 20 KT WITHIN THE LAST 24 HOURS. THE WAVE IS EMBEDDED IN A MODERATE MOIST ENVIRONMENT. A SHORTWAVE TROUGH IS CURRENTLY TO THE W OF THE WAVE ENHANCING CONVECTION NOT ONLY IN THE WAVE ENVIRONMENT BUT ACROSS THE CENTRAL CARIBBEAN FROM 65W-75W. THE WAVE IS FORECAST TO WEAKEN INTO A SURFACE TROUGH AND DISSIPATE WITHIN THE NEXT 24 HOURS. ...ITCZ/MONSOON TROUGH... THE ITCZ EXTENDS FROM 09N13W AND CONTINUES TO 04N31W TO 06N57W. ISOLATED SHOWERS ARE WITHIN 30 NM EITHER SIDE OF THE AXIS BETWEEN 25W AND 30W. ...DISCUSSION... ...THE GULF OF MEXICO... A MID TO UPPER-LEVEL TROUGH OVER THE CENTRAL UNITED STATES EXTENDS INTO THE WESTERN GULF OF MEXICO SUPPORTING A FRONTAL SYSTEM ANALYZED AS A COLD FRONT FROM SW ALABAMA NEAR 30N87W TO 26N91W TO A 1009 MB LOW OVER THE BAY OF CAMPECHE NEAR 20N96W. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE ALONG THIS FRONT AFFECTING THE GULF WATERS N OF 26N. THIS CONVECTION IS ALSO SUPPORTED BY A DIFFLUENT FLOW ALOFT GENERATED BY THE INTERACTION OF THE UPPER-LEVEL TROUGH PREVIOUSLY MENTIONED AND AN UPPER-LEVEL ANTICYCLONE ANCHORED OVER THE GULF OF TEHUANTEPEC THAT EXTENDS NE ACROSS THE BASIN. SCATTEROMETER DATA DEPICTS MODERATE NORTHERLY FLOW ACROSS THE NORTHERN GULF N OF THE FRONT WHILE MODERATE TO FRESH SOUTHERLY FLOW PREVAILS S OF THE FRONT. EXPECT FOR THE FRONT TO CONTINUE MOVING SE ACROSS THE BASIN WITH CONVECTION. WINDS ARE EXPECTED TO INCREASE BEHIND THE FRONT TO NEAR GALE FORCE WITHIN THE NEXT 48 HOURS. ...CARIBBEAN SEA... A TROPICAL WAVE IS IN THE EASTERN CARIBBEAN WITH AXIS ALONG 69W. PLEASE REFER TO THE SECTION ABOVE FOR DETAILS. THE UPPER-LEVEL ANTICYCLONE CENTERED OVER THE GULF OF TEHUANTEPEC ALSO EXTENDS ACROSS THE W CARIBBEAN MAINLY W OF 80W. A SHORTWAVE TROUGH EXTENDS FROM THE ATLANTIC ACROSS THE CENTRAL CARIBBEAN BETWEEN 73W-80W. AT THE SURFACE...A LOW IS CENTERED NEAR 11N82W. ALL THESE FEATURES COMBINE TO SUPPORT SCATTERED MODERATE CONVECTION ACROSS THE CENTRAL CARIBBEAN BETWEEN 66W-81W. SCATTEROMETER DATA DEPICTS MODERATE TO FRESH TRADES ACROSS THE BASIN. THE LOW IS FORECAST TO STAY NEARLY STATIONARY DURING THE NEXT 24 HOURS...ASSOCIATED CONVECTION WILL PERSIST THROUGH THIS PERIOD. A STRONG PRESSURE GRADIENT BETWEEN A RIDGE OVER THE W ATLANTIC EXTENDING ACROSS THE NORTHERN CARIBBEAN AND THE LOW IN THE SW BASIN WILL SUPPORT FRESH TO STRONG WINDS FROM 13N TO 16N BETWEEN 72W AND 77W WITH SEAS UP TO 9 FT. WINDS AND SEAS ARE FORECAST TO DIMINISH BY EARLY FRIDAY. ...HISPANIOLA... SCATTERED MODERATE CONVECTION ARE OVER THE CENTRAL CARIBBEAN INCLUDING HISPANIOLA SUPPORTED BY AN UPPER-LEVEL TROUGH EXTENDING FROM THE ATLANTIC TO A BASE NE OF COSTA RICA. THIS ACTIVITY IS EXPECTED TO DIMINISH WITHIN THE NEXT 24 HOURS AS THE TROUGH ALOFT MOVES E. ...ATLANTIC OCEAN... A WARM FRONT EXTENDS ACROSS THE W ATLANTIC FROM 31N80W TO 26N74W. TO THE E...AN UPPER-LEVEL TROUGH EXTENDS ACROSS THE CENTRAL ATLANTIC SUPPORTING A FRONTAL SYSTEM ANALYZED AS A COLD FRONT FROM 30N71W TO 31N46W. S OF THIS FRONT...A WEAKENING COLD FRONT IS FROM 24N70W TO 31N46W. SCATTERED MODERATE CONVECTION IS ALONG BOTH BOUNDARIES BETWEEN 41N70W. SCATTEROMETER DATA DEPICTS FRESH TO STRONG NORTHERLY WINDS N OF THE FRONTAL BOUNDARIES WHILE GENTLE TO MODERATE WINDS PREVAIL ELSEWHERE. A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL TROPICAL ATLANTIC. PLEASE REFER TO THE SECTION ABOVE FOR DETAILS. OVER THE NEXT 24 HOURS...THE WARM FRONT WILL CONTINUE MOVING N AWAY OF OUR AREA. THE COLD FRONTS OVER THE CENTRAL ATLANTIC WILL MERGE. CONVECTION IS EXPECTED ACROSS THE AREA. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ ERA