000 AGXX40 KNHC 290642 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 242 AM EDT MON SEP 29 2014 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 PREVIOUS/OFFICIAL BLENDED WITH THE GFS. MWW3 AND TAFB-NWPS USED TO ADJUST WAVE PARAMETERS. MEDIUM CONFIDENCE. A MID-LEVEL LOW IS CURRENTLY FORMING OVER SE LOUISIANA. THE MODELS INDICATE A WEAK SURFACE REFLECTION SHOULD DEVELOP WITHIN IN THE NEXT 12 HOURS AND QUICKLY MOVE E-NE INTO THE ATLC. THE 00Z GFS HAS TRENDED TOWARD A LESS WRAPPED UP SOLUTION IN THE ATLC WHICH KEEPS THE FRONT FROM PROGRESSING AS FAR S THROUGH THE EASTERN GULF AND FLORIDA ON MON AND TUE THAN THE 18Z RUN. THIS TREND IS IN LINE WITH THE MODEL CONSENSUS AND THE ENS MEAN. THE 00Z GFS LOOKS REASONABLE HERE. HIGH PRES BUILDS OVER THE AREA WED AND THU AND A NEW COLD FRONT MOVES INTO THE NW GULF FRI WITH LITTLE FANFARE. WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW THE ADVISORY CRITERIA OF 20-25 KT AND 8 FT THROUGH FRI NIGHT. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS/OFFICIAL FORECAST. TAFB-NWPS AND MWW3 USED TO ADJUST WAVE PARAMETERS. HIGH CONFIDENCE. THE SUBTROPICAL HIGH HAS BEEN COMPROMISED BY A DEEP-LAYERED TROUGH STRETCHED FROM THE CENTRAL ATLC THROUGH THE N CENTRAL CARIBBEAN INTO THE SW CARIBBEAN. THIS TROUGH IS WEAKENING AS THE LEADING EDGE OF THE UPPER TROUGH PROGRESSES EASTWARD WHILE THE LOW OVER BERMUDA STAYS PUT...ALLOWING HEIGHTS TO RISE BETWEEN THE TWO FEATURES. THE SURFACE RIDGE IS BEGINNING TO BUILD JUST N OF THE CARIBBEAN INVOF 22N. THIS IS INCREASING THE PRES GRADIENT. WINDS TO 25 KT WERE OBSERVED BY THE 0210Z ASCAT-A PASS NEAR 12N66W. THE AREA OF 20-25 KT WINDS IS EXPECTED TO EXPAND AND GRADUALLY SHIFT W THROUGH THU MORNING. AFTERWARD...INCREASED TROUGHING OVER THE SW N ATLC WEAKENS THE RIDGE AND THE PRES GRADIENT ACROSS THE CARIBBEAN...SHIFTING THE STRONGEST WINDS BACK S AND E OVER THE S CENTRAL CARIBBEAN. THE GFS APPEARS REASONABLE WITH WINDS HERE AND WITH THE LARGER SCALE FEATURES DRIVING THEM. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: LATEST PREVIOUS/OFFICIAL BLENDED WITH THE GFS. MWW3 AND TAFB-NWPS USED TO ADJUST WAVE PARAMETERS. MEDIUM CONFIDENCE. THE MODELS AGREE ON ALLOWING THE LOW NEAR BERMUDA TO DEEPEN AS IT SLOWLY DRIFTS NORTHWARD TODAY THEN GRADUALLY DISSIPATE AS IT MOVES INTO THE LEADING EDGE OF THE BROAD TROUGH APPROACHING FROM THE E TONIGHT INTO TUE. THE BROAD TROUGH TO THE E SUPPORTS THE MID-LEVEL LOW NOTED IN THE GULF OF MEXICO SECTION CURRENTLY ORGANIZING OVER SE LOUISIANA. THIS SYSTEM IS EXPECTED TO MOVE E INTO THE ATLC...WITH SURFACE LOW PRES MOVING E-NW OFF THE SE GEORGIA COAST TONIGHT AND DRAGGING A COLD FRONT SOUTHWARD THROUGH NORTHERN AND CENTRAL FLORIDA MON NIGHT THROUGH TUE. THE 00Z GFS SHOWS BETTER AGREEMENT WITH THE 00Z GEFS AND 12Z/28 EC ENS MEANS WITH THE TRACK OF THE AREA OF LOW PRES THAN THE 12Z/28 ECMWF. THE GFS IS BETWEEN THE FASTER 00Z UKMET AND SLOWER 12Z/28 ECMWF. THE 00Z GEFS FIRST SHOWS A 10 PERCENT CHANCE OF WINDS REACHING ADVISORY CRITERIA OVER N CENTRAL WATERS EARLY WED MORNING...BUT BRIEFLY INCREASES THE ODDS TO 50-60 PERCENT IN NE WATERS BY WED AFTERNOON. RUN-TO-RUN CONSISTENCY IN THE TIMING OF WINDS AT OR NEAR ADVISORY CRITERIA IS NOT GREAT IN THE GFS...WITH SOME FEEDBACK LIKELY CAUSING SOME OF THE DISCREPANCIES. FOR NOW...THE BLEND OF THE 00Z GFS WITH THE PREVIOUS/OFFICIAL FORECAST HELPS TO DIMINISH WINDS IN PLACES WHERE THEY MAY BE OVER-INFLATED. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.