000 AGXX40 KNHC 131920 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 220 PM EST THU NOV 13 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. 12Z UPDATE... IN THE GULF OF MEXICO...THE 1642 UTC ASCAT-B PASS SHOWS 40 KT NW TO N WINDS WITHIN 60 NM OFF THE COAST OF TAMAULPAS FROM 22.5N TO 23.5N WHERE THE 1200 UTC GFS HAS 30-35 KT FORECAST FOR 1500-1800 UTC. THE HIGHER RESOLUTION 1200 UTC NAM IS PERFORMING BETTER...SHOWING 40 KT IN THIS AREA. THE NAM IS ALSO STRONGER WITH WINDS IN THE SW GULF...S OF THE AREA SAMPLED BY ASCAT. THE 0416 UTC ASCAT-B PASS HAD SHOWN GALES IN THIS AREA JUST OF OF HEROICA VERACRUZ EARLIER THAN GFS RUNS HAD INDICATED. WITH THE CORE OF THIS SHALLOW COLD AIRMASS STILL MAKING ITS WAY S...THE STRONGER NAM WAS FAVORED HERE AS WELL. THE 1200 UTC NAM HAS BACKED OFF SLIGHTLY AT 10-M TO 40 KT...BUT THE 0-30 MB AGL SHOWS 50 KT. GIVEN THE STRONG VERTICAL MIXING IN PLACE BETWEEN THE WARM WATERS OF THE SW GULF AND THIS COLD AIRMASS...WILL LIKELY STICK WITH 45 KT MAX WINDS FOR THIS EVENING. THE 1200 UTC NAM CONTINUES TO SHOW GALES THROUGH 1800 UTC FRI...BUT THE SREF PROBABILITIES DROP OFF SIGNIFICANTLY AFTER 1200 UTC. THE GFS CONCURS WITH THE SREF. WILL MAINTAIN FORECAST CONTINUITY AND DROP THE GALE BY 1800 UTC FRI. THE GFS HAS BEEN ON THE FASTER EDGE OF THE GUIDANCE WITH THE NEXT COLD FRONT EXPECTED TO PASS THROUGH THE GULF LATE SUN THROUGH THE END OF THE FORECAST PERIOD ON TUE. THE 1200 UTC ECMWF CONTINUES TO FAVOR A SLOWER SOLUTION. THE UKMET AND EC MEAN SIDE WITH THE OPERATIONAL EC WHILE THE CMC AND GEFS SIDE WITH THE GFS. THEREFORE...A BLEND OF THE GFS AND ECMWF WAS USED WITH THIS FRONT. BOTH MODELS AGREE ON GALE FORCE WINDS OVER THE WESTERN GULF BEHIND THE FRONT MON AND MON NIGHT. ELSEWHERE...MARINE CONDITIONS ARE EXPECTED TO REMAIN BELOW THE ADVISORY CRITERIA OF 20-25 KT FOR WIND THROUGH UNTIL LATE MON WHEN THE COLD FRONT APPROACHES THE NE FLORIDA COAST. SW FLOW AHEAD OF THE FRONT AND NW WINDS BEHIND THE COLD FRONT WILL LIKELY INCREASE WINDS TO 20-25 KT. A BLEND OF THE SLOWER/WEAKER ECMWF AND FASTER/STRONGER GFS WAS USED FOR THE FORECAST MON AND TUE IN THE SW N ATLC. ----------------------------------------------------------------- PREVIOUS DISCUSSION... ...GULF OF MEXICO... MODEL PREFERENCE: 00Z GFS BLENDED WITH PREVIOUS OFFICIAL FORECAST. NWPS FOR WAVE HEIGHTS. HIGH CONFIDENCE. AN ASCAT PASS FROM 04 UTC VERIFIED 30 TO 35 KT WINDS OVER THE FAR WESTERN GULF ALONG THE COAST OF MEXICO FROM THE MOUTH OF THE RIO GRANDE TO VERACRUZ BEHIND A STRONG COLD FRONT EXTENDING FROM THE FLORIDA BIG BEND AREA TO THE BAY OF CAMPECHE. THE CURRENT FORECAST IS ON TRACK SHOWING THE GALE WARNINGS CONTINUING THROUGH LATE TODAY OFF THE COAST OF TAMAULIPAS AND THROUGH TOMORROW MORNING OFF THE COAST OF VERACRUZ. THE EARLIER NWPS RUN INDICATED SEAS TO 17 FT OFF VERACRUZ TONIGHT WHICH IS REASONABLE GIVEN THE FETCH...DURATION AND INTENSITY OF THE WINDS. ELSEWHERE GENERALLY MODERATE TO FRESH NORTHERLY FLOW WITH 4 TO 6 FT SEAS WILL DOMINATE. FROM FRI THROUGH SUN...THE WINDS AND SEAS WILL DIMINISH FROM N TO S ACROSS THE GULF...WITH WINDS IN THE SW GULF 20 KT OR LESS BY LATE FRI...AND SEAS BELOW 8 FT FRI NIGHT. SE RETURN FLOW WILL ALREADY BE STARTING TO INCREASE OVER THE NW GULF FRI NIGHT AND SAT AHEAD OF THE NEXT COLD FRONT. THE FRONT WILL STALL FROM SW FLORIDA TO THE NW YUCATAN PENINSULA BY FRI NIGHT...THEN LIFT N AS A DISSIPATING WARM FRONT THROUGH SAT. FOR SUNDAY INTO EARLY NEXT WEEK...AN UPPER LEVEL TROUGH WILL DIG SOUTHWARD ALONG THE FRONT RANGE OF THE ROCKIES INTO THE SOUTHERN PLAINS. THE GFS REMAINS MORE AMPLIFIED THAN THE ECMWF OR UKMET. THE MAIN EFFECT AT THE SURFACE WILL BE THE DEVELOPMENT OF LOW PRES OVER COASTAL TEXAS BY LATE SAT NIGHT...AND THE LOW MOVING ACROSS LOWER MISSISSIPPI VALLEY THROUGH SUN. THE GFS AND UKMET SHOW A STRONG TRAILING COLD FRONT MOVING OFF THE TEXAS COAST LATE SUN...WITH THE ECMWF SLIGHTLY LATER. THERE IS MORE OF CONSENSUS SHOWING ANOTHER ROUND OF GALE FORCE WINDS ACROSS THE FAR WESTERN GULF BEHIND THIS FRONT...WITH EVEN THE ECMWF INDICATED 35 KT OFF NORTHERN TAMAULIPAS BY MIDDAY MONDAY. THIS EVENT MAY BE STRONGER THAN THE CURRENT ONGOING GALE WARNINGS...WITH STRONG GALE WARNINGS TO NEAR STORM WARNING POSSIBLE OFF VERACRUZ BY MON NIGHT/TUE MORNING JUDGING BY THE GFS WHICH USUALLY HAS A BETTER HANDLE ON THE STRENGTH OF THE WINDS IN THIS AREA. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 00Z GFS BLENDED WITH PREVIOUS OFFICIAL FORECAST. NWPS FOR WAVE HEIGHTS. HIGH CONFIDENCE. AN ASCAT PASS FROM AROUND 02 UTC INDICATED MODERATE TO FRESH NORTHERLY WINDS FUNNELING INTO THE WINDWARD PASSAGE WHERE STATIONARY FRONT EXTENDS TOWARD WESTERN JAMAICA. THIS WILL DIMINISH THIS MORNING AS HIGH PRES N OF AREA WEAKENS AND SHIFTS EAST. ELSEWHERE THE WEAK PRESSURE PATTERN WILL RESULT IN GENERALLY MODERATE TRADES WITH SEAS RANGING FROM 3-6 FT INTO SUN. THE PRES GRADIENT WILL STRENGTHEN SLIGHTLY ACROSS THE NW CARIBBEAN SAT INTO SUN WITH MODERATE TO FRESH NE WINDS EXPECTED AND EVEN 20 TO 25 KT OVER THE N CENTRAL CARIBBEAN S OF HISPANIOLA AS HIGH PRES BUILDS N OF THE AREA. WINDS AND SEAS WILL DIMINISH SLIGHTLY EARLY NEXT WEEK AS THE HIGH PRES N OF THE AREA WEAKENS AND SHIFTS EAST. FOR THE TROPICAL N ATLC WATERS W OF 55W...MODERATE TO FRESH BREEZE TRADES WINDS PERSIST ACROSS THE REGION WITH SEAS OF 6 TO 7 FT IN E SWELL. NO MAJOR CHANGES ARE ANTICIPATED FOR THE NEXT SEVERAL DAYS. NO MAJOR DIFFERENCES IN MODEL OUTPUT. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: 00Z GFS BLENDED WITH PREVIOUS OFFICIAL FORECAST. NWPS FOR WAVE HEIGHTS. HIGH CONFIDENCE. A SHARP UPPER TROUGH IS NOTED ALONG 64W SUPPORTING A WEAKENING COLD FRONT 31N63W TO THE WINDWARD PASSAGE. THE FRONT WILL BECOME DIFFUSE THROUGH TODAY LEAVING A TROUGH OVER THE WATERS N OF 27N E OF 75W. WEAK RIDGING IS BUILDING OVER THE WATERS N OF THE NORTHERN BAHAMAS BEHIND THESE FEATURES BUT THIS WILL BE SHORT LIVED AS ANOTHER COLD FRONT EMERGES OFF THE COAST OF NE FLORIDA LATE TODAY. THE FRONT WILL REACH FROM 31N73W TO SE FLORIDA BY LATE FRI. MODERATE TO FRESH NORTHERLY WINDS WILL FOLLOW THE FRONT FRI AND SAT WITH SEAS TO AT LEAST 7 FT. THE WINDS AND SEAS DIMINISH SAT INTO SUN AS THE FRONT STALLS E TO W ALONG ROUGHLY 27N. SE RETURN FLOW WILL INCREASE N OF THE NORTHERN BAHAMAS LATE SUN INTO MON...WITH FRESH STRONG SOUTHERLY FLOW BY LATE MON N OF 28N W OF 70W. ANOTHER COLD FRONT WILL EMERGE OFF THE COAST BY MON NIGHT WITH STRONG NW FLOW FOLLOWING. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... .GMZ017...W CENTRAL GULF FROM 22N TO 26N W OF 94W... GALE WARNING TODAY INTO TONIGHT. GALE CONDITIONS POSSIBLE MON INTO MON NIGHT. .GMZ023...SW GULF S OF 22N W OF 94W... GALE WARNING TODAY INTO FRI. GALE CONDITIONS POSSIBLE MON INTO TUE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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/CHRISTENSEN. NATIONAL HURRICANE CENTER.