000 AGXX40 KNHC 110817 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 317 AM EST FRI DEC 11 2015 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 WEAK 1018 MB HIGH HAS SHIFTED NE INTO THE NE GULF NEAR 29N85W WITH WEAK RIDGE SE TO SW PORTIONS. ANTICYCLONIC LIGHT TO MODERATE WINDS PREVAIL ACROSS ALL BUT W AND NW PORTIONS...WHERE OBS AND RECENT ASCAT PASSES SHOW FRESH SE TO S WINDS...AND BECOMING SSW ALONG UPPER TEXAS COAST. ASSOCIATED SEAS CURRENTLY GENERALLY LESS THAN 3 FT..EXCEPT 3-4 FT NW PORTIONS AND INTO TEXAS AND SW LA COASTAL WATERS. SOME MODEST SHIFTS IN RECENT GUIDANCE IN MED RANGE NOTED WITH 00Z RUNS. SFC HIGH IN NE GULF WILL SHIFT NE NEXT 24-48 HRS AND INTO W ATLC AS A DEVELOPING LOW AND FRONTAL SYSTEM MOVE INTO CENTRAL PLAINS...AND FLOW OPENS UP INTO THIS SYSTEM ACROSS W PORTIONS EARLY SAT AND THEN ACROSS ENTIRE BASIN SAT NIGHT. FRESH TO STRONG SE-S WINDS ACROSS W HALF OF BASIN TO DEVELOP LATE TONIGHT INTO SAT MORNING AND BUILD SEAS 5-8 FT...WITH POTENTIAL FOR ISOLATED AREAS 25-30 KT TEXAS COASTAL WATERS LATE MORNING THROUGH AFTERNOON...WITH SEAS REACHING TO 9 FT. GFS AND UKMET IN AGREEMENT ON MOVING FRONT OFF TEXAS COAST AFTER 12Z SUN AND REACHING MSY TO NEAR TUXPAN BY 00Z MON. ECMWF ABOUT 6 HRS SLOWER WHICH IS REFLECTED IN STRONGER PRES GRADIENT E OF FRONT AND LESS BEHIND. GFS SUGGESTING CHANCE FOR NARROW ZONES OF GALES ON BOTH SIDES OF FRONT SUN...WHILE ECMWF SHOWS BETTER CHANCE AHEAD OF FRONT SUN. BLEND OF GFS-ECMWF CURRENTLY YIELDING WINDS JUST BELOW GALE FORCE SUN AFTERNOON AND EVENING...AND CONFIDENCE INCREASING A BIT ON DEVELOPMENT OF BRIEF MINIMAL GALES AHEAD OF FRONT...BUT AS YET NOT BEING FORECAST. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS WEAK 1017 MB HIGH LOCATED N OF LINGERING FRONTAL BOUNDARY NEAR 30N74W AND HAVING MINIMAL INFLUENCE ON PRES GRADIENT AT PRESENT ACROSS THE CARIB AS LLVL FLOW HAS BECOME DIFFLUENT...WITH SE WINDS ACROSS E AND NE CARIB VEERING S ACROSS THE ATLC AND THEN SW AHEAD OF FRONTAL BOUNDARY...WHILE MODERATE TRADES PREVAIL CENTRAL PORTIONS. LLVL TROFFING HAS DEVELOPED ALONG ABOUT 80-81W IN RESPONSE TO PERSISTENT ACTIVE CNVTN ACROSS JAMAICA AND ERN CUBA REGION AND AHEAD OF UPPER TROFFING SHIFT SE INTO NW CARIB. AS THE UPPER TROUGH MOVES SLOWLY SE OVER THE WEEKEND...GLOBAL MODELS DEVELOP CUT OFF LOW ACROSS E CUBA/SE BAHAMAS...WITH ACTIVE WEATHER TO GRADUALLY SHIFT E AND NE AHEAD OF TROF AND INTO SE BAHAMAS AND ADJACENT ATLC BY LATE SAT. THIS TO INDUCE INVERTED TROFFING FROM HISPANIOLA NNW INTO ATLC. HOWEVER...MODELS SUGGEST THAT LINGERING FRONTAL BOUNDARY WILL PERSIST ALONG 24-25N THROUGH THE WEEKEND... AND RIDGE SHIFTING NE OUT OF GULF AND INTO W ATLC WILL SET UP ALONG 31-32N AND TIGHTEN PRES GRADIENT ACROSS THE CARIB FOR RETURN TO FRESH TRADES ACROSS MOST OF CENTRAL PORTIONS STARTING TONIGHT THROUGH THE WEEKEND BEFORE THE RIDGE SHIFTS SE LATE SUN INTO MON AND TRADES DIMINISH. MODELS IN DISAGREEMENT ON LOCATION AND AMPLITUDE OF INVERTED TROFFING EXPECTED TO DEVELOP...WITH GFS WITH HIGHEST AMPLITUDE AND FARTHER W...WHICH IN TURN PRODUCES FRESH NELY FLOW ACROSS THE NW CARIB AND LEE OF CUBA. HAVE GONE MORE TOWARDS THE ECMWF AND A MORE ENE FLOW. PEAK WINDS IN ASSOCIATION WITH THE FEATURE ACROSS THE BAHAMAS WILL BE LATE SAT AFTERNOON THROUGH SUN...AS WELL AS ACROSS THE NW CARIB...WHERE WINDS TO AROUND 20 KT AND SEAS 5-7 FT ARE EXPECTED. ACROSS THE TROPICAL N ATLANTIC...MODERATE TO LOCALLY FRESH TRADE WINDS AND SEAS TO 5-7 FT THIS MORNING ARE GENERALLY EXPECTED TO PREVAIL THROUGH MON...WITH EXPECTED TO SUBSIDE TO 5-6 FT SAT THROUGH SUN. MODERATE NLY SWELL GENERATE BEHIND CENTRAL ATLC COLD FRONT TO MOVE INTO WATERS SUN-MON...RAISING SEAS N HALF TO 6-7 FT. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS DEEP LAYERED LOW MOVING E OF BERMUDA DRAGS AN OLD COLD FRONT SW INTO CENTRAL BAHAMAS THIS MORNING WITH AREA OF 20-30 SW WINDS EXITING AREA AND POSSIBLE GALES JUST N OF HSF AREA. WEAK 1017 MB HIGH BEHIND FRONT NEAR 30N74W WILL SHIFT E AS LOW CONTINUES TO MOVE EWD THROUGH SAT THEN BECOME PART OF RIDGE AXIS EXTENDING NEARLY E-W ALONG ABOUT 32N LATE SAT THEN GRADUALLY REALIGNING NW TO SE SUN. THIS FRONTAL BOUNDARY DOES NOT APPEAR SIGNIFICANT IN MODEL GUIDANCE ATTM...HOWEVER UPPER TROUGH DYNAMICS MOVING EWD INTO BAHAMAS ATTM WILL MAINTAIN SOME BAROCLINICITY...AND MODELS RESPOND WITH STRONG PRES GRADIENT DEVELOPING N OF FRONT SAT AND SUN...WITH WINDS TO 30 KT EXPECTED IN ELONGATED BAND FROM ABOUT 68W ACROSS THE BAHAMAS AND INTO EXTREME SE FLORIDA...WHERE SEAS WILL BUILD 8-10 FT E OF BAHAMAS SAT AFTERNOON THROUGH NIGHT. FRONTAL BOUNDARY TO THEN LIFT NWD AND WEAKEN THROUGH SUN AS RIDGE TO N REALIGNS AND LLVL FLOW OPENS UP INTO FRONTAL SYSTEM ACROSS MS VALLEY. GFS SHOW HIGH AMPLITUDE TROFFING DEVELOPING OUT OF ACTIVE CNVTN THAT WILL PERSIST E OF UPPER TROF...INITIALLY ALONG ABOUT 70-71W FRI EVENING AND SHIFTING W THEN WNW THROUGH THE WEEKEND. HAVE USED A MODEL CONSENSUS TO CAPTURE THIS TROF POSITION AND ASSOCIATED GRADIENT WINDS N OF BOUNDARY...WITH MAX WINDS TO 30 KT SAT AFTERNOON AND NIGHT...WHILE GFS IS FORECASTING GALES DURING THAT TIME. MODELS NOW SHOWING NEXT GULF OF MEXICO COLD FRONT DRAGGING WEAKLY ACROSS NW PORTIONS LATE MON-TUE...WITH GFS FASTEST IN LATEST RUNS...AND LIKELY TOO FAST. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.