000 AGXX40 KNHC 171018 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 618 AM EDT SAT SEP 17 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. MID LEVEL TROUGH PERSISTS FROM NE MEXICO TO LOUISIANA COASTAL WATERS AND CONTINUES TO MAINTAIN UNSTABLE CONDITIONS ACROSS MUCH OF NW AND N CENTRAL PORTIONS WITH PULSING CONVECTION. ASSOCIATED LOW TO MID LEVEL TROUGH IN THAT SAME AREA WILL DRIFT GRADUALLY NW AND WEAKEN NEXT 48 HOURS. OTHERWISE...MILD MARINE CONDITIONS PREVAIL WITH SEAS 3 FT OR LESS. WEAK HIGH PRES EXPECTED TO DEVELOP NE PORTIONS BY TONIGHT AND SHIFT SLOWLY WWD NEXT FEW DAYS BEFORE COLLAPSING TUE-WED AND LEAVING LIGHT TO MODERATE FLOW ACROSS THE BASIN. A WEAK THERMAL TROUGH WILL DEVELOP OVER THE YUCATAN PENINSULA DURING THE LATE AFTERNOONS AND CONTINUE INTO THE EARLY EVENINGS. EXPECT GENTLE TO MODERATE NE-E WINDS TO DEVELOP EACH DAY ALONG THE N AND NW COASTS OF THE WESTERN YUCATAN PENINSULA BEGINNING IN THE LATE AFTERNOONS...AND ENDING BEFORE MIDNIGHT EACH NIGHT AS THE INVERTED TROUGH MOVES W-NW ACROSS THE SW GULF ACCOMPANIED BY 2-3 FT SEAS. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS. BROKEN ATLC RIDGE PRODUCING WEAK PRES GRADIENT ACROSS THE BASIN TODAY AND YIELDING LIGHT TO MODERATE TRADES. TRADES HAVE INCREASED TO STRONG ALONG THE NW COAST OF COLOMBIA TONIGHT AND WILL PERSIST THROUGH SUN NIGHT...WITH A MORE SIGNIFICANT WINDS EXPECTED TONIGHT WHEN ASSOCIATED SEAS SHOULD BUILD TO ABOUT 9 FT. A NNE TO SSW ORIENTATED TROUGH...ACCOMPANIED BY SCATTERED CONVECTION...EXTENDS ACROSS THE LEEWARDS AND IS FORECAST TO SHIFT W ACROSS THE NE CARIBBEAN THROUGH TONIGHT AND GRADUALLY LOOSE IDENTITY S OF PUERTO RICO ON SUN. A TROPICAL WAVE ALONG 55W WILL MOVE W THROUGH THE TROPICAL WATERS THROUGH THIS EVENING AND ACROSS E CARIBBEAN TONIGHT THROUGH MON. MOSTLY A MODERATE NE-E-SE WIND SHIFT EXPECTED WITH THE WAVE PASSAGE. NE TO E SWELL FROM TROPICAL CYCLONE KARL WILL REACH THE TROPICAL N ATLC WATERS LATE MON...WITH KARLS ASSOCIATED WINDS SWEEPING NW ACROSS THE WATERS N OF 17N E OF 57W TUE AND WED. TROPICAL STORM CONDITIONS ARE POSSIBLE ACROSS THESE TROPICAL N ATLC WATERS DURING THAT TIME. GFS AND ECMWF DO NOT DEPICT A TC DURING THIS TIME AND THUS IS HAS BEEN VERY DIFFICULT TO MANUALLY CREATE WIND AND WAVE GRIDS BEYOND TUE. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS. TS JULIA CONTINUES NEARLY STATIONARY ALONG 30N WITH SMALL ISOLATED AREAS OF DEEP CONVECTION FIRING ACROSS NE QUAD OVERNIGHT...AND REMAINS A STRONGLY SHEARED SYSTEM. BROAD WIND FIELD ACROSS THE N AND NW QUADRANTS HAS GENERATED A RESPECTABLE WAVE FIELD AIMED GENERALLY AT GA THROUGH CENTRAL FL COASTS. OVERNIGHT ALTIMETER PASS SHOWED MAX SEAS TO 11 FT WILL NW OF CENTER. WINDS TO 25 KT ACROSS THE NW AND SE QUADS ATTM WILL GRADUALLY LIFT OUT TO THE NE DURING THE NEXT 24 HOURS AND EXIT THE REGION SUN NIGHT. ELY SWELL FROM TS KARL WILL REACH THE SE WATERS LATE MON...WITH ASSOCIATED CONDITIONS PASSING THROUGH THE TROPICAL WATERS E OF 62W LATE MON NIGHT THROUGH TUE NIGHT...THEN KARL WILL MOVE NW THROUGH THE DISCUSSION WATERS BETWEEN 55W AND 65W ON TUE NIGHT THROUGH THU...AND PASSING THROUGH THE WATERS S OF BERMUDA ON FRI. AGAIN...GFS AND ECMWF NOT DEPICTING A TC DURING THIS TIME AND MY WAVE GRIDS ARE NOT A VERY ACCURATE DEPICTION OF THE EXPECTED SCENARIO...BUT ARE REASONABLE FOR DAY 4 AND 5. AS MODELS GET A BETTER FEEL FOR KARL...OR NHC FORECAST SHIFT TO WEAKER SYSTEM... WIND AND WAVE GRIDDED FORECASTS WILL IMPROVE NEXT FEW DAYS. .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... NONE. $$ *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANE WARNINGS.GOV/MARINE $$ .FORECASTER STRIPLING. NATIONAL HURRICANE CENTER.