000 AGXX40 KNHC 120820 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 420 AM EDT SUN MAY 12 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 INTO PREVIOUS GRID PACKAGE WEAK LATE SEASON COLD FRONT MOVING THROUGH NRN GULF THIS MORNING...CURRENTLY EXTENDING FROM JUST E OF KAAF TO NEAR 27.5N90W THEN ARCHING W-SW THEN SW TO NEAR TAMPICO MEXICO. SCENARIO IS SOMEWHAT COMPLEX AS THERE WERE PRE FRONTAL TROUGHS AHEAD OF FRONT TODAY SINKING SE AND KICKING OFF CNVTN...AND THE SEMIPERMANENT COASTAL LOW BETWEEN TUXPAN AND VERA CRUZ THAT REMAINS ATTM. I THINK OUR FRONTAL POSITIONS HAVE BEEN TOO FAR S ACROSS THE W GULF THIS EVENING...AND HAVE ADJUSTED MY PROGS ACCORDINGLY...AND IN A REASONABLE COMPROMISE BETWEEN GFS AND ECMWF. THERE IS NOT MUCH PUSH IN THE LOW LEVELS TO DRIVE THE FRONT MUCH FARTHER S ACROSS THE W GULF NEXT 24-48 HOURS AND I THUS DONT EXPECT FRONT TO MOVE TOO MUCH FARTHER S ALONG THE MEXICAN COAST. MEANWHILE...UPPER SUPPORT WILL PUSH E PORTION OF FRONT THROUGH BIG BEND REGION TODAY AND REACH FROM NEAR CEDAR KEY W-SW TO NEAR 26.5N93.5W TO TAMPICO AREA BY 00Z MON...THEN WEAKENING AND INTO EXTREME S FL AND W ACROSS THE GULF ALONG ABOUT 24N BY 00Z TUE...THEN THROUGH CENTRAL BAHAMAS TO NW COAST OF CUBA BY 00Z WED...WHERE W END DISSIPATES. NE GRADIENT FLOW BETWEEN COASTAL TROFFING ALONG MEXICAN COAST AND FRONT WILL PRODUCE A ZONE OF NEAR 20 KT WINDS IN BETWEEN THE TROUGH AND FRONT TODAY W OF 93W AND YIELD SEAS THERE NEAR 6 FT. OTHERWISE...MODERATE ANTICYCLONIC FLOW WILL BUILD IN BEHIND THE FRONT THROUGH TUE TO PRODUCE SEAS GENERALLY 4 TO 5 FT ACROSS A LARGE PORTION OF THE BASIN. NLY FLOW 15-20 KT IS EXPECTED ACROSS NE PORTIONS MON SPREADING S ALONG W COAST OF FLORIDA TO BUILD SEAS TO 5-6 FT THERE BY TUE. HIGH PRES CENTER THEN SINKS IN TO NE COASTAL WATERS BY TUE TO BRING MODERATE RETURN FLOW TO W PORTIONS THROUGHOUT REMAINDER OF THE WEEK. VERY ACTIVE CNVTN EXPECTED TO CONTINUE TODAY NEAR AND S OF FRONT ACROSS W PORTIONS BEFORE UPPER DYNAMICS SHIFT NE AND GENERALLY INTO ATLC BY LATE MON. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GFS/ECMWF BLEND INTO PREVIOUS GRID PACKAGE DEEP LOW PRES ACROSS THE ATLC N OF MONA PASSAGE CONTINUES TO BLOCK ATLC HIGH PRES RIDGE FROM BASIN...PRODUCING LIGHT TO MODERATE WINDS E OF 72W...WITH COLOMBIAN LLVL JET YIELDING ONLY 20 KT AT SURFACE PER RECENT 02-03Z ASCAT PASSES. MAX SEAS THERE MAY BE ONLY 7 FT ATTM. CARIB ELY WAVE OF PREVIOUS DAYS HAS MOVED W INTO EPAC AND IS INTERACTING WITH MONSOON TROUGH THERE. TPW ANIMIATIONS SHOW MAJORITY OF THE TROPICAL MOISTURE ACCOMPANYING THIS WAVE HAS SHIFTED W ACROSS CENTRAL AMERICA AND INTO THE EPAC. WEAK TROFFING WILL REMAIN ACROSS PR...MONA PASSAGE...AND E TIP OF DOM REP NEXT FEW DAYS AS THE DEEP LAYERED LOW DRIFTS W AND WEAKENS... MAINTAINING LIGHT TO MODERATE FLOW ACROSS THE NE CARIB. TRADES ACROSS SW PORTIONS AND COLOMBIA COASTAL WATERS TO RETURN TO 20-25 KT RANGE TONIGHT THROUGH WED AS HIGH PRES SHIFTS INTO SE U.S. AND THEN OFFSHORE BEHIND GULF OF MEXICO COLD FRONT. FRONT TO PUSH SE THROUGH BAHAMAS TUE AND BEGIN TO NUDGE TROFFING N OF MONA PASSAGE EWD...AND ACT TO BACK FLOW TO THE NE ACROSS MUCH OF CARIB W OF 75W. NE WINDS THROUGH YUCATAN CHANNEL EXPECTED TO INCREASE TO NEAR 20 KT BY EARLY TUE AND THEN THROUGH WINDWARD PASSAGE LATE TUE...INCREASING TO 20-25 KT WED NIGHT AS FRONTAL TROUGH CONTINUES TO MOVE E ACROSS THE ATLC. MINOR DIFFERENCES SEEN AMONG GLOBAL MODELS ACROSS THE BASIN THROUGH DAY 5. MIDDLE TO UPPER TROUGH AND VIGOROUS EMBEDDED VORTEX MOVING SE ACROSS NE CARIB REGION THIS MORNING WILL INTERACT WITH LLVL MOISTURE ACROSS THE ATLC E OF LEEWARDS NEXT 24 HOURS TO INDUCE SCATTERED CONVECTION WITH ISOLATED DEEP CELLS. OLD FRONTAL BOUNDARY/SHEAR LINE PERSISTS ACROSS THE AREA AND WILL PROVIDE THE NEEDED MOISTURE TODAY. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GFS-ECMWF BLEND INTO PREVIOUS GRID PACKAGE VIGOROUS DEEP LAYERED VORTEX WITHIN UPPER TROUGH MOVING SE ACROSS ATLC HAS CARVED OUT A SURFACE LOW IN PAST 24 HOURS THAT WAS DRIFTING E TO NE...BUT HAS SINCE BECOME DECOUPLED FROM UPPER VORTEX...AND IS NOW MOVING SW...CENTERED NEAR 23N67W. FRONTAL LIKE TROUGH/CONVERGENCE BOUNDARY SPIRALS OUT OF LOW TOWARDS THE SE THEN S THEN SW INTO ERN PUERTO RICO...AND WILL ACT AS CONVERGENCE BOUNDARY NEXT 24-48 HOURS AS THROUGH DRIFTS W. I LIKE THE STRUCTURE OF THIS LLVL FEATURE IN THE GFS...BUT 12Z RUN OF ECMWF WAS ONLY GLOBAL MODEL SHOWING WWD DRIFT OF LOW IN THE SHORT TERM AND WILL TREND TOWARDS THIS MODEL THROUGH 48 HOURS BEFORE FRONTAL SYSTEM SPANKS TROUGH BACK TOWARD THE E AND SE BY DAY 3. FORTUNATELY...UPPER CONVERGENCE IN SW QUAD OF UPPER LOW HAS MOVED INTO PUERTO RICO TONIGHT AND WILL SPARE PR AND DOM REP OF HIGHLY UNSTABLE CONDITIONS TODAY...BUT SUFFICIENT MID LEVEL TURNING WILL STILL PRODUCE BRIEF LIFT. DYNAMICS IS SE QUAD OF LOW WILL SHIFT E-SE AND ACROSS THE NRN LEEWARDS AND ADJACENT TROPICAL ATLC WATERS TODAY FOR ACTIVE CONVECTION ALONG OLD FRONTAL ZONE MENTIONED ABOVE. 02-03Z ASCAT PASSES SHOWED WINDS 20-25 KT WITHIN 240 NM ACROSS THE NRN SEMICIRCLE OF THE SURFACE LOW...WHILE BUOY 41046 HAS CLIMBED BACK TO 10 FT THIS MORNING. A BROAD ZONE OF 20-25 KT WINDS AND SEAS 7-9 FT WILL REMAIN DRAPED ACROSS THE TOP OF LOW TODAY AND GRADUALLY SHIFT N AND NE IN ADVANCE OF GULF OF MEXICO COLD FRONT TONIGHT INTO MON. FRONT EXPECTED TO MOVE OFF NE FL COAST TONIGHT THEN REACH FROM NEAR 30N73W TO NW BAHAMAS AND MIAMI AREA 00Z TUE THEN JUST SE OF BERMUDA THROUGH CENTRAL BAHAMAS TO NW CUBA BY 00Z WED. LOW WILL WEAKEN QUICKLY WITH NO UPPER SUPPORT THIS AFTERNOON AND TONIGHT...AND BECOME ELONGATED N TO S TROUGH BY ABOUT 24 HOURS...DRIFTING W THEN BEGIN TO DRIFT BACK TOWARDS THE E TUE AND WED AHEAD OF FRONT. HIGH PRES BEHIND FRONT WILL PRODUCE FRESH N WINDS ACROSS MUCH OF AREA W OF FRONT BEGINNING EARLY TUE THEN DECREASE BY LATE TUE AS FRONT CONTINUES TO SHIFT SE...WITH 20 KT WINDS CONFINED TO NARROW ZONE BEHIND FRONT. SEAS WILL BUILD TO 8 FT ACROSS NE PORTIONS N OF 27N BEHIND FRONT BY LATE TUE. RECENT GFS RUNS WERE CONSIDERABLY FASTER THAN OTHER GLOBAL MODELS BY IS NOW VERY MUCH IN LINE WITH UKMET WITH FRONTAL BOUNDARY...AND AM BLENDING LESS ECMWF INTO THIS PACKAGE. .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.