000 AGXX40 KNHC 130642 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 242 AM EDT SUN SEP 13 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. NWPS BLENDED WITH PREVIOUS OFFICIAL FOR WAVES. HIGH CONFIDENCE. A THERMAL TROUGH WILL DEVELOP EACH AFTERNOON OVER THE YUCATAN PENINSULA. THE TROUGH WILL MOVE W-NW INTO THE SW GULF WATERS DURING THE EVENING THROUGH LATE NIGHT HOURS...THEN DISSIPATE BY LATE MORNING. THE STRONGER GFS SEEMS REASONABLE HERE. IT BRIEFLY CARRIES 20-25 KT WINDS ALONG THE NW COAST OF THE YUCATAN PENINSULA MON NIGHT WHEN RIDGING TO THE N WILL FORCE A SLIGHTLY STRONGER PRESSURE GRADIENT. MULTIPLE LOW-LEVEL BOUNDARIES OVER THE GULF OF MEXICO WILL MERGE TODAY...WITH THE REMAINING BOUNDARY EXPECTED TO STRETCH FROM NEAR SARASOTA FLORIDA TO TAMPICO MEXICO BY TONIGHT. THERE IS STILL SOME HINT IN THE MODELS AT A LOW PRES CENTER DEVELOPING ON THE TAIL END OF THE FRONT LATER TODAY AND MEANDERING AROUND TAMPICO MEXICO THROUGH MON NIGHT BEFORE DISSIPATING. THE MODELS THEN AGREE ON PUSHING THE WEAKENING BOUNDARY NORTHWARD...WITH THE DISSIPATING BOUNDARY EXPECTED TO EXTEND FROM NEAR CEDAR KEY FLORIDA TO BROWNSVILLE TEXAS MON NIGHT...AS THE SUPPORTING UPPER LEVEL TROUGH PULLS NORTHEASTWARD. THE UPPER PATTERN OVER THE GULF WILL BECOME MORE AMPLIFIED BY TUE AS A SHARP TROUGH PUSHES W INTO THE CENTRAL GULF. AT THE SURFACE...A N TO S TROUGH IS EXPECTED OVER THE EASTERN GULF BY TUE NIGHT AND SHOULD MIGRATE W TO AROUND 88W BY THU NIGHT. AT NO TIME DURING THE FORECAST PERIOD ARE WINDS AND SEAS EXPECTED TO EXCEED THE ADVISORY CRITERIA OF 20-25 KT AND 8 FT...RESPECTIVELY. THERE APPEARS TO BE NO SIGNIFICANT REASON TO STRAY FROM THE GFS FORECAST. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 00Z GFS BLENDED WITH PREVIOUS OFFICIAL. NWPS BLENDED WITH PREVIOUS OFFICIAL FOR WAVES. MEDIUM CONFIDENCE. THE 0244Z ASCAT-B PASS SHOWED A SOLID AREA OF 20-25 KT WINDS ALONG THE NE COAST OF COLOMBIA AHEAD OF A TROPICAL WAVE. NONE OF THE MODELS WERE STRONG ENOUGH WITH THESE WINDS...SO MANUAL ADJUSTMENTS WERE MADE TO THE GRIDS. THE MODELS ARE IN RELATIVELY GOOD AGREEMENT ON THE RIDGING N OF THE AREA DRIVING THE TRADE WINDS THROUGH TUE. AFTER THIS TIME...THE FORECAST BECOMES MORE UNSURE. THE 12Z ECMWF BECOMES MORE AMPLIFIED AT THE SURFACE THAN THE OTHER MODELS...WITH STRONGER RIDGING OVER THE BAHAMAS AND SHARPER TROUGHING DEVELOPING OVER THE CENTRAL ATLC TO THE NE OF THE NE CARIBBEAN. THE 00Z UKMET TRENDED AWAY FROM THIS SOLUTION AND TOWARD THE 00Z GFS WHICH DEVELOPS A TROPICAL LOW FARTHER E OF THE FORECAST AREA AND CARRIED WEAKER RIDGING IN THE BAHAMAS. THE 00Z GFS DIMINISHES THE FRESH TO STRONG N-NE WINDS ALONG THE COAST OF COLOMBIA AFTER WED. THIS SEEMS REASONABLE GIVEN THE EXPECTED PATTERN. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL. NWPS BLENDED WITH PREVIOUS OFFICIAL FOR WAVES. HIGH CONFIDENCE. THE 00Z GFS AND 12Z ECMWF CARRY FRESH TO STRONG E WINDS ALONG THE N COAST OF HISPANIOLA AS THE TROPICAL WAVE PASSES THROUGH THE REGION THIS MORNING. THE MOST RECENT ASCAT PASSES CONFIRM THE FRESH TO STRONG WINDS THERE. THE GFS GENERALLY PERFORMS BETTER HERE UNDER EASTERLY FLOW AND...AS EXPLAINED IN THE SECTION ABOVE...IT IS THE PREFERRED SOLUTION WITH THE RIDGING OVER THE BAHAMAS FROM TUE ONWARD. ITS SOLUTION WAS USED HERE. THE FORECAST ONLY CALLS FOR A FRESH TO STRONG BREEZE TO CONTINUE...PRIMARILY IN THE EVENINGS...THROUGH MON AS THE TROPICAL WAVE EXITS THE REGION. THE 0248 UTC ASCAT PASS SHOWED 20-25 KT SW WINDS OVER NW WATERS AHEAD OF THE DEEP-LAYERED TROUGH PUSHING INTO THE AREA. THE MULTIPLE LOW-LEVEL BOUNDARIES CURRENTLY OVER THE SE U.S. AND GULF OF MEXICO SHOULD MERGE TODAY. THE STRENGTHENED MERGED BOUNDARY SHOULD CONTINUE TO SUPPORT A FRESH TO STRONG BREEZE THROUGH THE AFTERNOON BEFORE THE UPPER LEVEL IMPETUS RAPIDLY PULLS NE AWAY FROM THE AREA...WEAKENING THE SURFACE FRONT. THE 12Z ECMWF WAS BETTER INITIALIZED...BUT BEEFING UP THE GFS A FEW KNOTS PRODUCED THE DESIRED RESULTS. THE FRONT WILL PUSH SE...STRETCHING FROM 31N75W TO VERO BEACH FLORIDA TONGIHT BEFORE RETREATING N AS A WARM FRONT AND WEAKENING...DISSIPATING ALONG 29N-30N W OF 75W MON NIGHT AS THE REMAINDER OF THE FRONT MOVES E-SE. HIGH PRES CENTERED N OF THE AREA SHOULD DOMINATE THE REGION THE REMAINDER OF THE PERIOD. AGAIN...THE GFS IS PREFERRED. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 SCHAUER. NATIONAL HURRICANE CENTER.