000 AGXX40 KNHC 170557 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 157 AM EDT FRI APR 17 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 WHICH WAS A GFS/ECMWF BLEND. TAFB NWPS USED FOR WAVE PARAMETERS. MEDIUM-HIGH CONFIDENCE. LOW LEVEL SOUTHERLY RETURN FLOW AND DIFFLUENT UPPER FLOW AHEAD OF A SERIES OF UPPER TROUGHS MOVING E FROM THE SOUTHERN PLAINS THROUGH THE LOWER MISSISSIPPI VALLEY WILL MAINTAIN THE POTENTIAL FOR SCT SHOWERS/ISOLATED TS ACROSS THE NW AND N-CENTRAL GULF WATERS THROUGH THE UPCOMING WEEKEND. ADDITIONALLY OBSERVATIONS REPORT EMBEDDED AREAS OF 3-5 NM VSBY IN PATCHY FOG OVER THE NW WATERS...AND THIS WILL BE DENOTED IN THE WEATHER GRIDS FOR THIS MORNING. A SURFACE RIDGE EXTENDING SW FROM THE FL BIG BEND TO ACROSS THE SW GULF WATERS WILL SHIFT SLIGHTLY SE TODAY ALLOWING A WEAK COLD FRONT TO MOVE OFF THE TX COAST TONIGHT...BUT IMMEDIATELY STALL...AND MOVE BACK INLAND ON SAT AND THE RIDGE REBUILDS W. THE RIDGE WILL SHIFT SE AGAIN ON SUN NIGHT ALLOWING ANOTHER COLD FRONT TO MOVE E ACROSS THE N-CENTRAL AND NE WATERS ON MON AND MON NIGHT. NE-E POST FRONTAL FLOW WILL INCREASE TO 15- 20 KT ACROSS THE NW WATERS ON TUE. EXPECT THE LOCALIZED EVENING THERMAL ENHANCEMENT ALONG THE NW COAST OF THE YUCATAN PENINSULA TO BE IN THE 20-25 KT RANGE EACH EVENING THROUGH SAT EVENING...THEN ONLY A 15-20 KT EVENTS EACH EVENING THROUGH THE REMAINDER OF THE PERIOD. THESE E-SE PULSES WILL PROPAGATE W ACROSS THE E BAY OF CAMPECHE DURING THE MORNING DAYLIGHT HOURS WITH THE TROUGH LOSING IDENTITY OVER THE CENTRAL BAY OF CAMPECHE BY EARLY AFTERNOON. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL WHICH WAS A GFS/ECMWF BLEND. TAFB NWPS USED FOR WAVE PARAMETERS. MEDIUM-HIGH CONFIDENCE. ATLC RIDGING N OF THE AREA...COMBINED WITH LOW PRES OVER NW COLOMBIA...WILL SUPPORT 20-25 KT NE WINDS WITHIN 180 NM OF THE NW COAST OF COLOMBIA TONIGHT...SAT AND SUN NIGHTS...THEN THE AFFECTED AREA SHOULD SHRINK TO WITHIN 90 NM OF THE COAST EACH NIGHT THROUGH TUE NIGHT. E-SE TRADES WILL INCREASE TO 20-25 KT ACROSS THE GULF OF HONDURAS EACH NIGHT WITH SEAS BUILDING TO 8 FT...NOTING THAT THE AFFECTED AREA WILL EXPAND N TO ALONG 18.5N ON SUN AND MON NIGHTS. MODERATE TO FRESH TRADES EXPECTED ELSEWHERE. NE SWELL WILL PROPAGATING SW THROUGH THE TROPICAL ATLC WATERS E OF LEEWARDS INCREASING THE COMBINED SEAS TO 8 FT ON SAT NIGHT...WITH THESE CONDITIONS SPREADING S ACROSS THE TROPICAL WATERS E OF THE WINDWARDS ON SUN AND MON. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL WHICH WAS A GFS/ECMWF BLEND. TAFB NWPS USED FOR WAVE PARAMETERS WITH MANUAL ADJUSTMENTS ACROSS WATERS N OF 27N E OF 60W. MEDIUM- HIGH CONFIDENCE. A BROAD COLD FRONT EXTENDS FROM 29N55W TO 27.5N65W TO 29N71W THEN BECOMES QUASI-STATIONARY INTO A 1016 MB LOW PRES AT 32N78W...WITH A WEAK SECOND COLD FRONT EXTENDING S FROM THE LOW ACROSS CENTRAL FL. NE-E 20-25 KT FLOW CURRENTLY OBSERVED N AND NE OF THE FRONTS WILL DIMINISH TO 15-20 KT EARLY TODAY AS THE COLD FRONT PORTION CONTINUES SE ACROSS THE DISCUSSION WATERS E OF 65W. THE SEGMENT OF THE FRONT BETWEEN 65-75W WILL LIFT NE AS A WEAK WARM FRONT. THE SURFACE LOW WILL ALSO LIFT NE TODAY WHILE DRAGGING THE SECOND WEAK COLD E ACROSS THE WATERS N OF THE BAHAMAS TONIGHT...BUT ONLY ACCOMPANIED BY A SW-W-NW 10 KT WIND SHIFT. THE SECOND COLD FRONT WILL ACCELERATE E ON SAT REACHING FROM BERMUDA TO THE NW BAHAMAS ON SAT EVENING...THEN STALL E-W BETWEEN 25-27N ON SUN AND GRADUALLY WASH OUT THROUGH TUE. SOUTHERLY FLOW WILL INCREASE TO 15-20 KT OVER THE NW WATERS ON SUN NIGHT AND MON AHEAD OF A ANOTHER WEAK COLD FRONT MOVING E OFF THE SE GA/NE FL COASTS ON MON NIGHT. THIS THIRD COLD FRONT WILL REACH FROM 31N73W TO THE NW BAHAMAS ON TUE NIGHT. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.