000 AGXX40 KNHC 101951 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 245 PM EST THU JAN 10 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... THE LATEST SURFACE ANALYSIS OF 18 UTC DEPICTS THE COLD FRONT ALONG A POSN FROM SW LOUISIANA TO 25N95.5W WHERE IT BECOMES STATIONARY SW TO INLAND THE COAST OF MEXICO JUST N OF TAMPICO. A SQUALL LINE PRECEDED THE FRONT FROM NEW ORLEANS SSW TO 26N93W TO 23N94W. BOTH SATELLITE IMAGERY AND NWS DOPPLER RADAR ANIMATIONS VIVIDLY DISPLAY NUMEROUS STRONG CONVECTION ALONG THE FRONT...BETWEEN THE FRONT AND THE SQUALL LINE AS WELL AS WITHIN 120-150 NM E OF THE SQUALL LINE. FREQUENT LIGHTNING STRIKES ARE CLEARLY NOTED WITH THIS CONVECTION. THE MOST RECENT AND LATEST BUOY AND PLATFORM OBSERVATIONS REVEAL DEEP LAYER MOIST SE WIND FLOW AHEAD OF THE FRONT AND SQUALL FUELING THE CONVECTION. THIS FLOW IS CHARACTERIZED AS SE-S WINDS OF 20-25 KT N OF 25N BETWEEN THE SQUALL LINE AND 87W. SEAS THERE ARE IN THE 5-8 FT WITH THE HIGHEST OF THE RANGE IN AND NEAR THE DEEP TSTM ACTIVITY. THE ASCAT PASS FROM NEAR 1552 UTC THIS MORNING SHOWED A SWATH OF SE 20-25 KT WINDS ACROSS MUCH OF THE EASTERN PART OF THE GULF PRIMARILY S OF 27N. BUOYS THERE ARE REPORTING SIMILAR WIND CONDITIONS. THE 12 UTC GFS AND UKMET MODEL RUNS ARE SIMILAR WITH RESPECT TO TO VORTICITY SIGNAL ALIGNED WITH THE STRONG CONVECTION OUT AHEAD OF THE SQUALL LINE...WHILE THE ECMWF IS MORE SUBTLE. OF NOTE... THE BNDRY LAYER WINDS OF THE ECMWF AND GFS ARE VERY SIMILAR TO THE NOTED OBSERVATIONS. SATELLITE WATER VAPOR IMAGERY CLEARLY DEPICTS A DEEP LAYER TROUGH PRESENTLY MOVING INTO THE FAR WRN GULF PORTION. AN ASSOCIATED EMBEDDED INTENSE DEEP LAYER VORTEX IS LIFTING NNE OVER ERN OKLAHOMA. THESE FEATURES SUPPORT AN OCCLUDED FRONTAL SYSTEM OVER THE MID-WEST REGION OF THE COUNTRY WITH THE RELATED COLD FRONT BEING THE ONE MENTIONED ABOVE. SATELLITE WATER VAPOR ALSO SHOWS A LARGE AREA OF DEEP LAYER RIDGING ENCOMPASSING THE GULF TO THE E OF THE COLD FRONT. MODELS INDICATE THAT THIS FEATURE WILL ONLY SLOWLY MOVE E THROUGH SAT ALLOWING FOR THE FRONT TO MAKE VERY SLOW PROGRESS...WHILE AT THE SAME TIME THE DEEP LAYER TROUGH AND ASSOCIATED VORTICITY LIFTS NEWD. WITH THIS IN MIND...WILL FORECAST THE COLD FRONT TO SLOWLY REACH A POSN FROM NEAR SE LOUISIANA TO THE WESTERN BAY OF CAMPECHE THIS EVENING WHERE IT WILL STALL AND DISSIPATE BY FRI. MODELS THAN SUGGEST THAT ATLC HIGH PRES BUILDS WESTWARD ACROSS THE ERN AND MIDDLE GULF FRI THROUGH SUN. THEY ALSO SUGGEST THAT THE NEXT COLD FRONT ENTERS THE FAR WRN GULF EARLY ON SUN... AND JUST LIKE THE PRESENT ONE...SLOWLY PROGRESSES EWD TO A POSN FROM NEAR SE LOUISIANA TO SW GULF BY EARLY TUE. WITH AN AREA OF HIGH PRES EXPECTED TO BUILD SE BEHIND THIS NEXT FRONT AS OPPOSE TO THE CURRENT ONE...EXPECT NLY FLOW OF ABOUT 20-25 KT TO SURGE S ACROSS THE WRN GULF BEGINNING LATE SUN AND INTO TUE. WINDS E OF THIS FRONT SHOULD BE LIGHT TO MODERATE IN SE-S RETURN FLOW AROUND THE WRN PERIPHERY OF THE ATLC HIGH THAT BUILDS WWD. CARIBBEAN SEA AND TROPICAL N ATLC S OF 22N W OF 55W... THE 1414 UTC ASCAT PASS FROM THIS MORNING VIVIDLY SHOWED A LARGE SWATH OF NE-E 25-30 KT WINDS OVER MUCH OF THE CENTRAL CARIBBEAN PORTION S OF ABOUT 17N. A POCKET OF GALE FORCE WINDS OF 30-35 KT WAS EMBEDDED WITHIN THIS SWATH FROM JUST NW OF THE COLOMBIAN COAST TO NEAR 14N BETWEEN 72W AND 78W. A FEW SHIPS IN THE AREA ARE REPORTING SEAS IN THE RANGE OF 10-16 FT NEAR THE COAST OF COLOMBIA...AND SEAS OF 8-13 FT ELSEWHERE OVER THE CENTRAL PORTION OF THE CARIBBEAN. A GALE WARNING REMAINS IN EFFECT FOR THE SW PORTION OF THE SEA FROM 11N TO 14N BETWEEN 72W AND 78W BASED IN THIS DATA ...AND GOOD INITIALIZATION OF THE GFS/UKMET/ECMWF WITH RESPECT TO THESE WIND CONDITIONS. THE 12 UTC GFS MEAN ENSEMBLE...LIKE THE 00 UTC GFS MEAN ENSEMBLE SHOWS NO CHANCE OF A GALE FROM FRI AFTERNOON ONWARD. THIS SEEMS PLAUSIBLE AS THE STRONG WRN ATLC RIDGE IS FORECAST BY THE GLOBAL MODELS TO PRESS S AND WEAKEN THROUGH THE UPCOMING WEEKEND. ELSEWHERE...FRESH TO STRONG TRADES IN THE NW CARIBBEAN AND THE WINDWARD PASSAGE ARE EXPECTED TO DIMINISH FRI INTO THE WEEKEND AS THE RIDGE IN THE SW N ATLC WEAKENS. ERN CARIBBEAN SEAS ARE IN THE 7-10 FT IN NE SWELLS PER BUOY 42059 AT 15N67.5W. SIMILAR CONDITIONS ARE NOTED IN THE NRN AND CENTRAL PORTIONS OF THE TROPICAL N ATLC ZONES WATERS AS SEEN IN BUOYS THERE. ELSEWHERE OVER THE TROPICAL N ATLC...WINDS HAVE DIMINISHED TO S FRESH BREEZE COMPARED WITH THIS TIME LAST NIGHT AND SEAS WILL CONTINUE TO SUBSIDE THROUGH SAT AS A LOW PRES SYSTEM DIVES SOUTHEASTWARD INTO THE CENTRAL ATLC AND WEAKENS THE SUBTROPICAL RIDGE THERE. AS OBSERVED IN PREVIOUS FORECAST DISCUSSIONS...THE ECMWF WAVE GUIDANCE IS A BIT FASTER IN CARRYING THE SWELL FROM THE CENTRAL ATLC SYSTEM S INTO THE TROPICAL ATLC THAN THE GFS BASED GRIDDED WWIII GUIDANCE BUT VERY CLOSE TO THE NAH GRIDDED WAVEWATCH. FOR THIS FORECAST PACKAGE WILL BLEND THE 12 UTC GRIDDED WWIII AT 50/50 WITH THE PREVIOUS FORECAST WHERE IT HAD ALREADY INCORPORATED SOME OF THE ECMWF GUIDANCE...AND MAKE MINOR TWEAKS (UP THE SEAS 1-2 FT) IN THE SW CARIBBEAN SEA THROUGH FRI NIGHT IN THE AREA OF THE GALE WARNING..AND MINOR TWEAKS TO ELSEWHERE. SW N ATLC S OF 31N W OF 55W... THE 1412 UTC ASCAT PASS SHOWED FRESH TO STRONG TRADEWINDS S OF 24N N OF THE ANTILLES...WITH A SMALL POCKET OF NE-E 25-30 KT WINDS NEAR THE NRN PORTION OF THE WINDWARD PASSAGE. WITH A TIGHT PRES GRADIENT IN PLACE OVER THE MUCH OF THE WRN PORTION OF THE BASIN...EXPECT LITTLE CHANGE IN THESE WIND CONDITIONS THROUGH FRI NIGHT AT WHICH TIME THE STRONG HIGH CENTER LOCATED N OF THE AREA DROPS S AND WEAKENS. SEAS WILL REMAIN IN THE HIGH RANGE IN RESIDUAL N SWELLS THROUGH THE WEEKEND OVER THE SRN AND ERN PORTIONS OF THE BASIN. THE AFOREMENTIONED SYSTEM IN THE CENTRAL ATLC BECOMES A PLAYER PRIMARILY OVER WATERS E OF 70W FRI INTO THE WEEKEND. AS MENTIONED IN THE SECTION ABOVE...THE GRIDDED WAVEWATCH III IS SLOWER THAN THE ECMWF WAVE GUIDANCE TO SPREAD THE SWELL WESTWARD INTO THIS AREA. WILL KEEP CONTINUITY WITH PREVIOUS FORECAST THINKING WITH RESPECT TO WAVE HEIGHTS PRIMARILY IN THE ERN AND SE PORTIONS OF THIS BASIN THROUGH THE PERIOD. THE 12 UTC ECMWF AND GFS HAVE BACKED DOWN ON NLY WINDS IN THE FAR NE CORNER OF THE AREA TONIGHT THROUGH FRI WITH THE GUIDANCE NOW SHOWING 15-20 KT. GALE FORCE WINDS ARE EXPECTED IN THE HFSAT2 AREA WELL E OF 55W BEGINNING EARLY FRI AFTERNOON. WEAKENING HIGH PRES MOVES S OF 31N NEAR 73W ON SAT...THEN LINGERS INTO EARLY NEXT WEEK...SIMILAR TO A SPRING PATTERN SCENARIO... WITH NO COLD FRONTS EXPECTED TO INTRUDE INTO THE AREA. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE WARNINGS... GULF OF MEXICO... .NONE. CARIBBEAN SEA AND TROPICAL N ATLC... .GALE WARNING...AMZ031 THROUGH FRI MORNING. SW N ATLC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE