000 AGXX40 KNHC 041957 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 256 PM EST FRI JAN 04 2013 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC...AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... FRONTAL BOUNDARY HAS STALLED ACROSS THE WRN GULF W OF 88W WHILE DRIFTING SWD AND BECOMING DIFFUSE AND MORE DIFFICULT TO IDENTIFY E OF 88W PER RECENT OBS AND VIS IMAGERY. STLT IMAGERY WOULD SUGGEST THAT WEAKENED BOUNDARY NEARING EYW BUT DEEPER INVESTIGATION LEADS US TO MAINTAIN BOUNDARY ACROSS SW FLORIDA COASTAL WATERS TO NEAR 22N94W TO NEAR 19N93W. S FLORIDA DEWPOINTS HAVE NOT CHANGED MUCH IN PAST SEVERAL HOURS AND WIND IS LIKELY BRIDGING OVER FRONT W OF THE PENINSULA WHILE SEA BREEZE DOMINATES ACROSS S FL. GALE WARNING WAS DROPPED WITH 12Z PACKAGE THIS MORNING...IN ACCORDANCE WITH GUIDANCE ON NO DATA SUGGESTING GALE CONTINUING. PEMEX PLATFORM BMO REPORTED WINDS JUST BELOW 30KT AND SEAS 4.4M (14FT) AROUND 12Z...AND EXPANDED AREA OF 8-10 FT SEAS ABOVE WW3 FOR AFTERNOON FORECAST BASED ON THIS AND ECWAVE. A 1618Z ASCAT METOP-A PASS SHOWED NW WINDS 25-30 KT ACROSS THE BMO PLATFORM AREA...WHILE A 1532Z ASCAT METOP-B PASS SHOWED SIMILAR WINDS. GIVEN ASCAT LOW BIAS AT THESE WIND VELOCITIES...MINIMAL GALES WERE LIKELY CONTINUING N OF 18.5N W OF THE FRONT AT 15-16Z...AND WILL ACCEPT A MISS ON THIS ONE. WINDS AND SEAS SHOULD GRADUALLY DIMINISH THROUGHOUT THE AFTERNOON AS THE FRONT MEANDERS...WITH WAVE ALONG FRONT PERSISTING ALONG 94W...AS FRONT LIFTS NORTHWARD IN RESPONSE TO MID AND UPPER LEVEL RIDGING BUILDING AHEAD OF A TROUGH MOVING E THROUGH THE SW UNITED STATES. THIS TROUGH WILL PROVIDE A SECONDARY SURGE OF NORTHERLY FLOW TO THE WESTERN GULF BY SUN...BUT IT IS NOT EXPECTED TO TRANSPORT PARTICULARLY COLD AIR. NEITHER THE 12 UTC GFS NOR THE 00 UTC ECMWF SHOW GALE FORCE WINDS NOR DOES THE 12 UTC GEFS SHOWS ANY CHANCES OF A GALE. HOWEVER...THE 1500 UTC SREF IS SHOWING LOW CHANCES BEGINNING 21Z SUN. IT GENERALLY DOES NOT TAKE STRONG CAA ADVECTION TO PRODUCE GALES IN THIS AREA...BUT WOULD ALSO LIKE TO SEE MORE DECISIVE MODEL AGREEMENT BEFORE PULLING THE TRIGGER ON A GALE WARNING HERE. HAVE THUS HELD ON TO 25-30 KT WINDS ACROSS THIS AREA. LATER IN THE PERIOD...CONFIDENCE DROPS FURTHER AS THE GFS AND ECMWF DIVERGE WITH THEIR HANDLING OF THE NEXT TROUGH TO IMPACT THE REGION. CARIBBEAN SEA AND TROPICAL N ATLC S OF 22N W OF 55W...AN E-W RIDGE OVER THE SW N ATLC ALONG 24-25N DOMINATES THE WIND REGIME IN THE CARIBBEAN AND TROPICAL N ATLC. THE 1400 UTC ASCAT PASSES MISSED THE OFFSHORE COLOMBIA WATERS...WHERE HIGHEST WINDS ARE EXPECTED...BUT SHOW SOLID AREAS OF 20 KT WIND EXTENDING FROM THE NE CARIB S OF PR W-SW TO THE SW CARIB OFFSHORE OF NICARAGUA. HAVE USED THE GFS PER PREVIOUS SHIFT REASONING ACROSS THE CARIB...AS IT SHOWS THE STRONGEST WINDS OVER THE CENTRAL CARIBBEAN. THE 12 UTC GFS SHOWS WINDS TO GALE FORCE ALONG THE COAST OF COLOMBIA 06-12 UTC OVER THE WEEKEND...WHILE THE 12 UTC GEFS SHOWS 30 PERCENT PROBS FOR EARLY SUN ONLY. HAVE MAINTAINED THIS PULSING GALE FORECAST IN GRIDS BUT WILL NOT YO-YO WARNINGS AND KEEP UP GALE FOR THE ENTIRE PULSING PERIOD. ATTM...WILL ONLY GO WITH GALES THROUGH SUN MORNING. VERY BROAD ZONE OF STRONG TRADES ACROSS MUCH OF CARIB TO INCREASE CURRENT SEAS FURTHER...WITH LARGE AREA OF 10-15 FT SEAS BY SUN MORNING BETWEEN 70-80W. SW N ATLC S OF 31N W OF 55W... THE NORTHERN PORTION OF THE COLD FRONT REMAINS NEARLY STATIONARY THIS AFTERNOON W OF 75W...WHILE MOVING SSE E OF 75W...EXTENDING FROM 30N65W TO NEAR FORT PIERCE FLORIDA. E PORTIONS WILL RACE EASTWARD THROUGH THE WEEKEND WHILE THE PORTION OVER FLORIDA AND JUST N OF THE BAHAMAS REMAINS RELATIVELY STATIONARY. THE NEXT DEEP-LAYER TROUGH WILL MOVE OFF THE MID-ATLC U.S. COAST ON SUNDAY AND FINALLY SEND THE WEAK FRONT E OF FLORIDA. FRESH WINDS ARE CURRENTLY CONFINED TO NEAR THE LEADING EDGE OF THE FRONT N OF 30N. AS THE FRONT MOVES E...SO WILL THE FRESH BREEZE OVER N WATERS. A SECOND FRONT WILL SLOWLY MOVE OFFSHORE SUN AND WINDS WILL INCREASE BOTH AHEAD AND BEHIND THE FRONT BY MON...WITH A FRESH TO STRONG BREEZE EXPECTED OVER MUCH OF THE AREA BY TUE. AS MENTIONED IN THE GULF OF MEXICO SECTION...THE GFS IS ALIGNED WITH THE MODEL CONSENSUS AND ENSEMBLES IN THE LATER PORTION OF THE FORECAST PERIOD. WW3 HAS BEEN TO FAST IN LOWERING SEAS ACROSS THE TROPICAL N ATLC AND CENTRAL TROPICAL ATLC AND HAVE LEANED VERY STRONGLY ON WW3/FNMOC ENSEMBLE AND ECWAVE FOR THIS AREA...RUNNING 2-3 FT HIGHER THAN WW3. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .NONE. CARIBBEAN SEA AND TROPICAL N ATLC... .GALE WARNING...AMZ031. SW N ATLC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER STRIPLING