000 AGXX40 KNHC 201832 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 232 PM EDT TUE SEP 20 2016 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W...AND THE SW N ATLANTIC INCLUDING THE BAHAMAS. ...GULF OF MEXICO... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS. A WEAK SURFACE TROUGH EXTENDS FROM THE NE GULF NEAR 29N83W TO 1013 MB LOW PRES NEAR 27N88W TO 23N93W. SCATTERED SHOWERS AND ISOLATED TSTMS CONTINUE TO FIRE NEAR THESE FEATURES WITH THE ASSISTANCE OF MID-UPPER LEVEL TROUGHING. THE SURFACE FEATURES ARE FORECAST TO DRIFT WESTWARD ACROSS THE BASIN THROUGH WED NIGHT...APPROACHING THE NW GULF COAST LATE WED NIGHT. WEAK HIGH PRES WILL DEVELOP IN THE N CENTRAL GULF NEAR SE LOUISIANA THU THROUGH THE UPCOMING WEEKEND. FAIRLY BENIGN MARINE CONDITIONS ARE EXPECTED TO CONTINUE WITH GENTLE WINDS AND SEAS 2 FT OR LESS. WINDS WILL INCREASE IN THE WESTERN GULF FRI THROUGH SUN AS THE PRES GRADIENT TIGHTENS. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS. ATLC RIDGE REMAINS N OF 35N AND BLOCKED FROM BUILDING INTO THE REGION WITH DEEP LAYERED TROUGHING FROM JUST SE OF BERMUDA SW TO CENTRAL BAHAMAS. LIGHT TO MODERATE TRADES PERSIST ACROSS THE BASIN W OF 60W WITH SEAS GENERALLY 5 FT OR LESS...EXCEPT FOR STRONG NE TO E WINDS TO AROUND 20 KT ACROSS S CENTRAL PORTIONS AND ALONG THE NW COAST OF COLOMBIA...WHERE SEAS REMAIN LESS THAN 8 FT. A WEAK TROPICAL WAVE ALONG 73W CONTINUES TO INTERACT WITH UPPER LOW SHIFTING SLOWLY WESTWARD ACROSS EASTERN CUBA WHICH WILL CONTINUE TO PRODUCE ACTIVE WEATHER ACROSS N CENTRAL PORTIONS THROUGH TONIGHT. THE TROPICAL WAVE WILL REACH THE WESTERN CARIBBEAN LATE TONIGHT INTO EARLY WED...MOVING ACROSS CENTRAL AMERICA THU THROUGH FRI. CONDITIONS ASSOCIATED WITH TROPICAL CYCLONE KARL WILL MOVE ACROSS THE FAR NE PORTION OF TROPICAL N ATLC WATERS...GENERALLY N OF 17N/18N THROUGH TONIGHT...BEFORE VEERING MORE NW AND LIFTING OUT OF THE AREA. ASSOCIATED E-NE SWELL HAS ALREADY BEGUN TO MOVE INTO THE AREA DURING PAST 24 HOURS AND BEGINNING TO BLEED THROUGH THE CARIBBEAN PASSAGES OF THE LESSER ANTILLES. ONCE KARL BEGINS THE NW MOTION...LITTLE SWELL ENERGY IS EXPECTED TO PROPAGATE SW ACROSS THE NE CARIBBEAN. OTHERWISE...LITTLE CHANGE IN MARINE CONDITIONS IS ANTICIPATED THROUGH THE UPCOMING WEEKEND. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS. A DEEP LAYERED LOW TO MIDDLE LEVEL TROUGH EXTENDS FROM JUST SE OF BERMUDA TO THE CENTRAL BAHAMAS AND BLOCKS THE ATLC RIDGE...WITH AN ATTENDANT SURFACE TROUGH ACROSS THE WATERS W OF 77W. THIS TROUGHING WILL DRIFT NW OVER THE NEXT 24-48 HRS AND BECOME DIFFUSE WHILE CONTINUING TO ACT AS A CONVERGENCE ZONE FOR AREAS OF CONVECTION. MEANWHILE...TROPICAL STORM KARL CONTINUES TO STRUGGLE AND HAS BEEN PULSING WITH CONVECTION PAST 12-24 HOURS. RECENT VISIBLE SATELLITE IMAGERY INDICATES AN EXPOSED CENTER...AND THUS LITTLE STRONG WIND STILL NOT LIKELY ACROSS THE SW SIDE OF KARL. KARL WILL MOVE ACROSS ZONE AMZ127 THROUGH TODAY AND TONIGHT...THEN GRADUALLY VEER MORE NW WED AND THU AND IS EXPECTED TO GRADUALLY INTENSIFY. THE CURRENT NHC FORECAST MOVES KARL NEAR 65W THU NIGHT THROUGH FRI BEFORE CURVING TO THE NE THIS WEEKEND. A WEAK PRES PATTERN TO THE W AND SW OF KARL WILL PRODUCE LIGHT TO MODERATE WINDS AND SMOOTH SEAS...DOMINATED BY SWELL FROM KARL. .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS II COLLABORATION CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... .AMZ127...ATLANTIC FROM 19N TO 22N BETWEEN 55W AND 65W... TROPICAL STORM WARNING TODAY INTO WED. $$ *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANE WARNINGS.GOV/MARINE $$ .FORECASTER LEWITSKY. NATIONAL HURRICANE CENTER.