000 AGXX40 KNHC 010801 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 401 AM EDT WED MAY 1 2013 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: GFS/ECMWF MODELS WITH AVERAGE CONFIDENCE. SECTORIZED GFS IN WESTERN GULF TO CAPTURE HIGHER WINDS BEHIND FRONT. A SHARP NEGATIVELY TILTED MID/UPPER LEVEL SHORT WAVE TROUGH IS PUSHING THROUGH THE NW GULF THIS MORNING...SUPPORTING A LARGE AREA OF CONVECTION OVER THE WARM WATERS OF THE LOOP CURRENT IN THE CENTRAL PORTION OF THE GULF. A RECENT ASCAT PASS FROM 0330 UTC CAPTURED A COUPLE OF TRANSIENT MESOSCALE TROUGHS EMBEDDED IN THE DOMINANT SE FLOW ACROSS THE GULF. THE MAIN SYNOPTIC PATTERN AT THE SURFACE CONSISTS OF A SERIES OF SUCH TROUGHS THROUGHOUT THE GULF MIGRATING ON THE PERIPHERY OF HIGH PRES WELL NE OF THE AREA...WITH GENTLE TO MODERATE SE RETURN FLOW OVER THE WESTERN GULF. THE SHORTWAVE TROUGH WILL LIFT OUT TODAY AHEAD OF A MAJOR DISTURBANCE MOVING THROUGH THE ROCKIES INTO THE CENTRAL PLAINS AND MISSISSIPPI VALLEY OVER THE NEXT COUPLE OF DAYS. MODELS ARE IN GOOD AGREEMENT REGARDING THE TIMING OF AN ASSOCIATED COLD FRONT MOVING OFF THE TEXAS COAST BY THU AFTERNOON. THERE IS BETTER ACCORD CONCERNING THE LIKELIHOOD OF GALES BEHIND THE FRONT OFF THE COAST OF TAMAULIPAS IN GMZ017 EARLY FRI. THE GEFS IS CONSISTENTLY BULLISH WITH PROBABILITIES OVER 90%...IN LEAGUE WITH THE SREF. THE UKMET HAS JOINED THE GFS OPERATIONAL SHOWING GALES AT THIS TIME AS WELL...ALTHOUGH THE 00Z ECMWF IS STILL WEAKER WITH ONLY 30 KT. THE OTHER ISSUE IS THE CHANCE FOR GUSTS TO GALE FORCE OUTSIDE THE AREA OF SUSTAINED GALES. JUDGING BY SST'S AND MODEL STABILITY GUIDANCE...THE AREA FROM 24N TO 26N W OF 96W WILL LIKELY HAVE FREQUENT GUSTS TO GALE FORCE. WILL INCLUDE THIS AS PART OF THE GENERAL GALE WARNING AREA IN THE FORECAST AS A GENERAL GALE FOR CLARITY REASONS. THE VERACRUZ COAST FARTHER SOUTH IN GMZ023 REMAINS MORE TROUBLING. SREF GUIDANCE STILL CONTENDS A 50% CHANCE FOR GALES THERE BY AFTERNOON...S OF 22N W OF 95W. THIS IS A USUAL AREA FOR GALES BEHIND COLD FRONTS. HOWEVER...GIVEN THAT THIS IS MAY...AND THE SUN ANGLES ARE HIGH...THE COOL AIRMASS BEHIND THE FRONT SHOULD BE MODIFIED ENOUGH TO PREVENT SIGNIFICANT MIXING OF HIGHER MOMENTUM AIR FROM REACHING THE SURFACE. WILL HOLD OFF ON GALES FOR GMZ023. SEAS ARE BASED ON MWW3 OUTPUT WITH SOME ADJUSTMENTS UPWARD MADE IN THE NW GULF LATE THU TO ACCOUNT FOR FASTER WAVE GROWTH BEHIND THE FRONT. ELSEWHERE...THERE IS SOMEWHAT BETTER CONSENSUS AS WELL IN THE MODELS CONCERNING THE DEVELOPMENT OF A LOW IN THE GULF LATER IN THE WEEK...ALTHOUGH SOME DISCORD IN THE MODELS ON THE TRACK OF THE LOW INTO SAT. FORECAST FOLLOWS A GFS/ECMWF BLEND FOR NOW SHOWING THE LOW SHIFTING EASTWARD TOWARD THE W CENTRAL FLORIDA COAST BY SAT. THE FRONT BECOMES DIFFUSE THROUGH SAT AS IT DRIFTS EASTWARD. WINDS AND SEAS OVER THE WESTERN GULF DIMINISH SAT AS HIGH PRES BUILDS BEHIND THE FRONT. SAT INTO SUN REMAIN LESS CERTAIN AS MODELS DIVERGE FURTHER IN PLACEMENT AND INTENSITY OF THE LOW. BOTH GFS AND ECMWF SHOW A GENERAL WEAKNESS OVER THE FLORIDA PENINSULA...ALBEIT AT DIFFERENT ENDS OF THE STATE...WITH THE GEFS AVERAGING OUT A MORE GENERAL TROUGH OVER FLORIDA. THE EC ENSEMBLE IS AN OUTLIER...SHOWING ONLY A VERY BROAD TROUGHING ACROSS THE REGION. EXTENDED FORECAST FOLLOWS GFS/ECMWF BLEND. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GFS/ECMWF/PERSISTENCE BLEND WITH GOOD CONFIDENCE. HIGH PRES N OF REGION WILL MAINTAIN MODERATE TO FRESH BREEZES ACROSS TROPICAL N ATLC AND CENTRAL CARIBBEAN WITH GENTLE TO MODERATE E FLOW THROUGH MID WEEK...EXCEPT FRESH BREEZES EXPECTED ACROSS GULF OF HONDURAS TUE THROUGH THU AND ALONG COAST OF COLOMBIA. WINDS DIMINISH ACROSS BASIN LATER IN THE WEEK AS HIGH PRES N OF AREA SHIFTS E AND REPLACED BY WEAK LOW PRES TROUGH...WEAKENING PRES GRADIENT OVER REGION. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GFS/ECMWF BLEND WITH AVERAGE CONFIDENCE THROUGH WEAK AND LOW CONFIDENCE LATE IN PERIOD DUE TO LOW PRES TROUGH POSITION. SCATTEROMETER AND BUOY DATA FROM THE PAST SEVERAL HOURS SHOW A CLOSED LOW STARTING TO FORM NEAR 32N77W. MODELS ARE IN GOOD AGREEMENT SHOWING THIS FEATURE SHIFTING S TOWARD GRAND BAHAMA TODAY...THEN DAMPENING OUT AS HIGH PRES BUILDS N OF THE AREA. THE PATTERN STARTING THU AND PERSISTING THROUGH SUN FEATURES ENHANCED E WINDS N OF 28N W OF 70W IN AMZ11 AND AMZ113 DUE TO A TIGHTENING GRADIENT BETWEEN THE HIGH PRES N OF THE AREA CENTERED OVER THE NORTHEASTERN U.S. AND DEVELOPING LOW PRES IN THE E CENTRAL GULF OF MEXICO. DESPITE SOME MODEL DIFFERENCES WITH THE TRACK AND CHARACTER OF THE LOW PRES IN THE GULF...THE PATTERN CHANGES LITTLE FOR SW N ATLC ZONES. FORECAST REFLECTS GFS/ECMWF BLEND. .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... GMZ011...NONE. GMZ013...NONE. GMZ015...NONE. GMZ017...GALE CONDITIONS EXPECTED FRI. GMZ019...NONE. GMZ021...NONE. GMZ023...NONE. GMZ025...NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... AMZ011...NONE. AMZ013...NONE. AMZ015...NONE. AMZ017...NONE. AMZ019...NONE. AMZ021...NONE. AMZ023...NONE. AMZ025...NONE. AMZ027...NONE. AMZ029...NONE. AMZ031...NONE. AMZ033...NONE. AMZ035...NONE. AMZ037...NONE. AMZ039...NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... AMZ111...NONE. AMZ113...NONE. AMZ115...NONE. AMZ117...NONE. AMZ119...NONE. AMZ121...NONE. AMZ123...NONE. AMZ125...NONE. AMZ127...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.HURRICANES.GOV/MARINE $$ .FORECASTER CHRISTENSEN. NATIONAL HURRICANE CENTER.