000 AGXX40 KNHC 201710 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 110 PM EDT TUE OCT 20 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: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL. LATEST NWPS FOR WAVES WITH MANUAL ADJUSTMENTS FOR OBSERVATIONS. MEDIUM CONFIDENCE. BROAD DISSIPATING FRONTAL TROUGH OVER SE GULF IS ACCOMPANIED BY SCT RW WITH EMBEDDED ISOL TS WITH LITTLE CHANGE EXPECTED THROUGH WED...THEN MOISTURE GUIDANCE SHIFTS HIGHEST PRECIP CHANCE WILL SHIFT TO THE WESTERN GULF WATERS IN RETURN FLOW FROM THU-SUN. TIGHT GRADIENT BETWEEN HIGH PRES ACROSS SE CONUS AND BROAD LOW PRES OVER YUCATAN WILL MAINTAIN 20-25 KT E WINDS ACROSS THE E- CENTRAL GULF WATERS THROUGH TONIGHT...WITH CONDITIONS THEN QUICKLY DIMINISHING TO E-SE 15-20 KT THROUGHOUT WED...EXCEPT PULSING TO 20-25 KT OVER NW WATERS JUST OFFSHORE SE TX ON WED AND THU NIGHTS. FRESH NW WINDS ALONG MEXICAN COAST NEAR 19N96W WILL DIMINISH TO 15-20 KT LATE THIS AFTERNOON. LOW PRES OVER THE YUCATAN WILL MOVE W ACROSS THE BAY OF CAMPECHE ON WED...THEN WEAKEN TO A NW TO SE ORIENTATED TROUGH FROM 22N97W TO 19N94W ON THU. E-SE 15-20 KT CONDTIONS FORECAST ACROSS MOST AREAS ON FRI AND SAT. A WEAK LOW IS EXPECTED NEAR 27N97W WITH A TROUGH EXTENDING S TO 20N96W ON SUN. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL. LATEST NWPS FOR WAVES WITH MANUAL ADJUSTMENTS FOR OBSERVATIONS. MED CONFIDENCE. A BROAD N TO S ORIENTATED LOW LEVEL TROUGH LIES UNDER AN UPPER CYCLONE OVER THE W CARIBBEAN ALONG 86W...AND IS ACCOMPANIED BY CONSIDERABLE CLOUDS/CONVECTION ATTM. THE TROUGH AND ASSOCIATED CONDITIONS SHOULD GRADUALLY SHIFT W OVER THE YUCATAN THROUGH WED. UPPER DIFFLUENCE E OF AN UPPER TROUGH WILL SUPPORT SCT RW/ISOL TS ELSEWHERE ACROSS NW AND N-CENTRAL CARIBBEAN THROUGH THE END OF THE WEEK. A WEAK COLD FRONT WILL MOVE INTO THE N- CENTRAL CARIBBEAN ON THU-FRI. A TROUGH...OR WEAK TROPICAL WAVE...ANALYZED FROM 10-16N ALONG 54W WILL MOVE W ACROSS THE TROPICAL WATERS S OF 15N ON WED AND INTO THE SE CARIBBEAN ON WED NIGHT AND THU...WITH GUIDANCE DISSIPATING THE TROUGH BY FRI. EXPECT ONLY A SLIGHT ENHANCEMENT OF CONVECTION MAINLY E OF THE TROUGH AXIS. EXPECT NOCTURNAL ENHANCEMENT OF 20-25 KT ALONG THE NW COAST OF VENEZUELA AND NE COAST OF COLOMBIA TONIGHT AND WED NIGHT. OTHERWISE GENTLE-MODERATE TRADES FORECAST THROUGH PERIOD. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL. LATEST NWPS FOR WAVES WITH MANUAL ADJUSTMENTS FOR OBSERVATIONS.. MEDIUM CONFIDENCE. A BROAD FRONTAL BOUNDARY EXTENDS SW FROM 31N52W ACROSS THE NORTHERN BAHAMAS TO THE FL STRAITS AND IS PRECEDED BY A TROUGH FROM 28N55W TO 22N62W. AN ASSOCIATED BROAD BAND OF DENSE OVERCAST MULTILAYERED CLOUDS WITH EMBEDDED SCT RW/ISOL TS IS SHIFTING ACROSS THE AREA S OF A LINE FROM 31N55W TO SE FL WITH NE-E 20-30 KT LOW LEVEL WINDS OBSERVED IN THE SAME AREA BUT EXPECTED TO DIMINISH TO 20-25 KT THIS AFTERNOON. COMBINED SEAS OF 8-12 FT EXIST E OF THE BAHAMAS...AND 6-9 FT SEAS ARE OBSERVED THROUGHOUT THE FL STRAITS AND EXPOSED BAHAMIAN WATERS. BUILDING HIGH PRES TO N WILL PUSH THE FRONT E LATER TODAY...THEN STALLING FROM 31N59W TO THE WINDWARD PASSAGE ON WED AND THU WITH THE NE FLOW W OF THE FRONT DIMINISHING TO 15-20 KT ON FRI. A BLEND OF GUIDANCE SUGGESTS A COUPLE OF SURFACE LOWS WILL DEVELOP ALONG THE FRONT ON THU NIGHT. THE SOUTHERN WEAK LOW WILL DEVELOP NEAR 23N69W AND QUICKLY RACE NE ALONG THE FRONT. A STRONGER LOW WILL DEVELOP NEAR 31N62W AND QUICKLY LIFT N OF THE AREA DRAGGING THE FRONT E AGAIN ON FRI. THE FRONT WILL STALL FROM 31N59W TO HISPANIOLA ON SAT...THEN DRIFT W ON SUN. NE-E 15 KT WINDS EXPECTED W OF THE FRONT ON SAT AND 10-15 KT ON SUN. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 NELSON. NATIONAL HURRICANE CENTER.