000 AGXX40 KNHC 110807 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 407 AM EDT SAT MAY 11 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 BLEND ATLC RIDGE CENTERED ACROSS CENTRAL ATLC EXTENDS SW TO S FL AND THEN WEAKLY INTO FAR E GULF THIS MORNING YIELDING LIGHT TO MODERATE SE TO S WINDS ACROSS WATERS E OF 86W...AND SEAS 3 FT OR LESS. OUTFLOW BOUNDARY HAS SHIFTED SE INTO NE CENTRAL GULF PAST FEW HOURS AND DISSIPATED...LEAVING WEAK TROFFING FROM NEAR KAAF SW TO NEAR 90W WHILE BROAD LOW PRES DOMINATING MUCH OF MEXICO IS MAINTAINING SUFFICIENT PRES GRADIENT ACROSS W PORTIONS OF GULF TO PRODUCE MODERATE E TO SE WINDS AND SEAS 4-5 FT...EXCEPT 15-20 KT AND 5-6 FT OFF N COAST OF YUCATAN. WEAK FRONTAL BOUNDARY IS APPROACHING TEXAS COAST ATTM WITH VERY ACTIVE CONVECTION FIRING ALONG AND AHEAD OF BOUNDARY UNDER SWLY FLOW ALOFT. FRONT FORECAST TO SHIFT SE TO ALONG TEXAS COAST BY THIS EVENING...AND THEN ACROSS N GULF BY SUN EVENING...THEN INTO SW N ATLC TO S FL AND ACROSS SRN GULF BY MON EVENING. GLOBAL MODELS IN REASONABLE AGREEMENT ON FRONTS WITH MODEST DIFFERENCES. WITH WEAK THERMAL ADVECTION ASSOCIATED WITH FRONTS THIS TIME OF YEAR I MUST ADMIT DIFFICULTY IN PLACING FRONTAL POSITIONS FOR MY DAY 1-3 PROGS...AND HAVE TAKEN A GFS-ECMWF CONSENSUS...LEANING MORE ON ECMWF BY DAY 3. JET DYNAMICS S OF SINKING UPPER TROUGH ACROSS U.S. WILL RESULT IN CONTINUED ACTIVE CONVECTION ALONG FRONTAL BOUNDARY AND CONVERGENCE LINES AHEAD OF IT NEXT 48 HOURS BEFORE LLVL MOISTURE BEGINS TO BE SHEARED OUT TO THE NE MON. NELY WIND EXPECTED TO INCREASE BEHIND WEAK FRONTAL BOUNDARY ACROSS W GULF SUN WITH GFS INCREASING TO 20-25 KT OFF CENTRAL MEXICAN COAST...WHILE ECMWF INCREASES WINDS A BIT LATER...BY 00Z MON. THIS AIDED BY WEAK INVERTED TROFFING FORECAST BY MODELS TO LINGER ACROSS SW GULF. SEAS TO INCREASE TO 5-7 FT AS THIS NE FLOW FRESHENS SUN EVENING AND NIGHT...POSSIBLY TO 8 FT SHOULD WINDS SUSTAIN AT THIS STRENGTH OVERNIGHT. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GFS-ECMWF BLEND MODERATE ELY TRADES PREVAIL ACROSS THE BASIN E OF 82W ATTM AS DEEP LAYERED TROUGH N OF PR AND HISPANIOLA CONTINUES TO BLOCK ATLC HIGH PRES RIDGE FRONT BUILDING ACROSS BASIN. SE FLOW PREVAILS W OF 82W BECOMING SSE THROUGH THE YUCATAN CHANNEL...WHILE RECENT PARTIAL ASCAT PASSES DEPICTED E TO SE WINDS 20-25 KT ACROSS GULF OF HONDURAS WHERE SEAS LIKELY 6-7 FT ATTM. LACK OF STRONGER PRES GRADIENT ONLY YIELDING 20 KT THROUGH SRN CARIB INVOF OF TYPICAL LLVL JET. ELY WAVE MOVING ACROSS SW CARIB PAST 36 HOURS NOW APPEARS TO HAVE ENTERED FAR EPAC WATERS WHILE WEAK ELONGATED TROUGHING PREVAILS ALONG 10-11N IN THE SW CARIB. RECENT ASCAT PASS AT 0318Z SUGGESTS SOME LLVL TROFFING OFFSHORE OF COSTA RICA...BUT THAT COULD BE MONSOON TROF UNDULATING WITH ELY WAVE. MOISTURE ASSOCIATED WITH THIS ELY WAVE WILL CONTINUE TO SHIFT W ACROSS CENTRAL AMERICA AND EXTREME SW CARIB TODAY FOR SCT CNVTN THERE...WHILE WAVE ATTEMPTS TO BECOME BETTER ORGANIZED ACROSS THE EPAC NEXT FEW DAYS. LITTLE SIGNIFICANT CHANGES EXPECTED IN PATTERN ACROSS THE CARIB THROUGH SUN UNTIL GULF OF MEXICO FRONT MOVES INTO S FL AND BACKS FLOW TO NE ACROSS NW PORTIONS SUN NIGHT-MON. DEEP LAYERED TROUGH N OF HISPANIOLA TO LIFT OUT MON BUT WEAKNESS EXPECTED TO PERSIST ALONG 70W IN THE SW N ATLC THROUGH TUE AND PREVENT ATLC RIDGE FROM BUILDING INTO CARIB. TO THE CONTRARY...HIGH SINKING INTO N GULF OF MEXICO TO INFLUENCE FLOW ACROSS W PORTIONS OF BASIN BY TUE...WITH NE TO NNE WINDS TO PREVAIL TUE W OF 78W. AGAIN...AM LEANING MORE STRONGLY TOWARD THE ECMWF BY DAY 3. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GFS-ECMWF BLEND A VIGOROUS UPPER TROUGH SWINGING E ACROSS THE AREA NOW NEARING 67W AND HAS CARVED A DEEP LAYERED TROUGH TO THE SURFACE DURING THE PAST 24 HOURS...WITH STLT SUGGESTING A SUB TROPICAL APPEARANCE. MODELS DID NOT HAVE GOOD HANDLE IN THIS YDA AND SIGNIFICANT HAND EDITS WERE NECESSARY THROUGH RECENT 00Z RUNS. STILL NO INDICATION OF A SURFACE LOW ATTM...BUT WITH TROUGH FROM ROUGHLY 23N66W TO NE TIP OF HISPANIOLA. ATLC HIGH CENTERED TO THE NE INDUCING GRADIENT FLOW 20-25 KT AT LEAST ACROSS NE SEMICIRCLE OF LLVL CYCLONIC CIRCULATION NEAR 23N67W. BUOY 41046 HOVERING BETWEEN 8 AND 9 FT PAST FEW HOURS SHOWER 41045 REMAINING AT 8 FT PAST FEW HOURS. HIGHEST SEAS NEAR 10 FT LIKELY OCCURRING NEAR 24N65W AND WILL INTRODUCE INTO GRIDS FOR UPCOMING PACKAGE. OTHERWISE...LIGHT TO MODERATE ANTICYCLONIC FLOW PREVAILS ACROSS THE AREA AROUND THIS FEATURE. UPPER TROUGH FORECAST TO CONTINUE SHIFTING E AND SE NEXT FEW DAYS AND WILL GRADUALLY DECOUPLE FROM LLVL CYCLONE AND TROFFING EARLY SUN. MODELS SUGGEST SURFACE TROUGH TO ATTEMPT TO PERSIST UNDER UPPER TROUGH AND SHIFT SLIGHTLY NE NEXT 12-18 HOURS BEFORE DECOUPLING OCCURS AND TROUGH SHIFTS W TO NW UNDER INFLUENCE OF ATLC SURFACE RIDGE. REMNANTS TO BE PULLED NW THEN N AHEAD OF FRONTAL ZONE MOVING OFF E COAST OF U.S. SUN NIGHT AND MON...BUT WITH LLVL WEAKNESS PERSISTING N OF HISPANIOLA WHICH THEN SHIFTS SLOWLY E AS DEEP LAYERED TROUGH AND FRONTAL ZONE MOVE E INTO ATLC MON-TUE. TRIED TO CAPTURE THE GFS EVOLUTION OF SURFACE TROUGH THROUGH DAY 3-4 WHILE LEANING TOWARD BROADER SCALE MOVEMENT OF FRONT PER THE ECMWF. .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...NONE. 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 STRIPLING. NATIONAL HURRICANE CENTER.