000 AGXX40 KNHC 250813 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 413 AM EDT SUN AUG 25 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 MOISTURE CONVERGENCE CONTINUES EARLY THIS MORNING BETWEEN A SLOWLY SINKING COLD FRONT ACROSS THE FL PANHANDLE AND A WEAK LLVL TROUGH ACROSS THE NW GULF...YIELDING SCATTERED MODERATE TO STRONG CONVECTION ACROSS NE AND N CENTRAL PORTIONS AND BEING FUELED BYSELY FLOW NEAR 20 KT PER RECENT ASCAT PASS. BUOY OBS THERE SHOWING ONLY 3-4 FT ATTM WITH WW3 SUGGESTING POTENTIAL FOR PK SEAS NEAR 5 FT. FRONT TO SINK FURTHER S INTO NE GULF ALONG 29N AND MAINTAIN ACTIVE WEATHER ALONG AND S OF BOUNDARY...WITH ZONE OF ESE WINDS 15-20 KT TO THE S OF IT EXTENDING FROM NE PORTIONS ACROSS LOUISIANA COASTAL WATERS...WITH SEAS 4-5 FT. SECONDARY BOUNDARY TO MOVE S INTO N FLORIDA ATLC WATERS WITH RIDGING INDUCING NE TO E FLOW ACROSS FAR NE PORTIONS MON...THEN GRADIENT AND WINDS DIMINISHING TUE AS RIDGE SHIFTS E IN ADVANCE OF NEXT SHORT WAVE AND FRONTAL SYSTEM MOVING TO EASTERN SEABOARD. TROPICAL WAVE HAS MOVED OFF THE YUCATAN PENINSULA IN PAST 24 HOURS AND IS ILL DEFINED ACROSS THE W BAY OF CAMPECHE...AND HAS LEFT A LOW LEVEL LOW BEHIND...WHICH IS NOW EXITING THE COAST NEAR LA LAGUNA DE TERMINOS AND SHIFTING WNW...WITH SMALL BAND OF DEEP CNVTN ACROSS N SEMICIRCLE. GLOBAL MODELS SEEM TO WANT TO POSITION A SFC LOW WITH THE TROPICAL WAVE...AND FARTHER NW OF THIS LOW...BUT THIS FEATURE IS DEPICTED AT H85 BY MODELS. GFS SFC DEPICTION SEEMS REASONABLE...BUT ABOUT 6 HOURS FAST AND HAVE TRIED TO ALTER WIND FIELD TO MATCH OUR PROVISIONAL FCST...WITH LOW NEAR 20N95W AT 00Z MON AND INLAND NEAR 21.6N 98W BY 00Z TUE. HOWEVER... GIVEN CURRENT POSITION BASED ON STLT...THIS MAY ALSO BE A BIT FAST AND FURTHER ADJUSTMENT WILL BE NEEDED. EXPECT THIS LOW TO MOVE WNW TO NW NEXT 48 HOURS WITH AREA OF 25-30 KT WIND DEVELOPING ACROSS N AND NE SEMICIRCLES NEAR CNVTN...WITH BROAD ENOUGH 20 KT WIND FIELD TO PRODUCE SEAS TO 10 FT...POSSIBLY TO 11 FT BEFORE ENTERING COAST MON AFTERNOON/EVENING. HAVE USE OUR NWPS SWH OUTPUT FOR THIS PACKAGE THROUGH 48 HOURS IN HOPES THAT WE HAVE IMPROVED OUR WIND FCST ON MODEL GUIDANCE. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GFS SAL HAS SPREAD ACROSS MOST OF BASIN AHEAD OF TROPICAL WAVE IN E CARIB ALONG 67/68W ATTM. FRESH SELY FLOW BEHIND GULF OF MEXICO TROPICAL WAVE YIELDING WINDS TO 25 KT IN GULF OF HONDURAS AS FCST BY GFS. RECENT SCAT PASSES DEPICT AREA OF 25 KT WINDS OFF COAST OF COLOMBIA AND ENE FLOW 15-20 KT ALONG AND N OF WAVE RELATED CNVTN ACROSS ERN CARIB. THIS CNVTN OCCURRING ALONG SAL BOUNDARY WILL BE CAPABLE OF PRODUCE STRONG WIND GUSTS TO NEAR GALE FORCE. SEAS ACROSS THIS AREA RUNNING 5-7 FT PER RECENT ALTIMETER AND BUOY OBS AND WILL SHIFT W WITH WAVE NEXT 24-36 HOURS BEFORE ABATING AS ATLC RIDGE IS NUDGED EWD BY E COAST TROUGH AND FRONTAL SYSTEM. WAVE WILL CONTINUE W AND INTO W CARIB BY 00Z TUE WITH 20 KT WIND FIELD REMAINING GENERALLY N OF 14N AS IT MOVES THROUGH CENTRAL CARIB. WINDS IN GULF OF HONDURAS FCST TO REMAIN IN THE 20-25 KT RANGE THROUGH MON MORNING BEFORE DROPPING TO 10-15 KT NEXT FEW DAYS. GRADIENT ACROSS ENTIRE BASIN REALLY DROPS OFF BY TUE FOR MODERATE WINDS AND SEAS...AND POTENTIALLY NO 8 FT SEAS WITHIN THE BASIN. THIS WAVE ACROSS E CARIB LEFT AS A COMPLEX DOUBLE VORTEX WAVE AND WAS HUGE IN AREAL COVERAGE...AND HAS LEFT A WEAKNESS IN ITS WAVE ACROSS THE TROPICAL N ATLC WATERS AS IT HAS SEPARATED FROM MONSOON TROUGH. LIGHT TO MODERATE WINDS AND SEAS 5 FT OR LESS WILL PREVAIL NEXT 24 HOURS N OF 14N...WITH ENE WINDS 15-20 KT AND SEAS 5-6 FT N OF 14N. WEAK LOW ANALYZE NEAR 12N45.5W THIS MORNING I BELIEVE WAS THE EASTERN VORTEX OF THIS HUGE WAVE COMPLEX AND WILL LIMP WWD THROUGH THE AREA TUE AND WED...WITH MONSOON TROUGH AND WEAK WIND FLOW OCCURRING TO THE E OF REMNANTS OF THIS LOW. NEXT TROPICAL WAVE TO ENTER THE TROPICAL N ATLC WATERS LATE WED...WITH GFS SLIGHTLY SLOWER THAN THE EURO MODELS. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GFS FRONTAL BOUNDARY HAS SHIFTED SSE INTO NW PORTIONS OF THE AREA THIS MORNING...WITH AMPLE MOISTURE AND CONVECTION OCCURRING S OF IT. SUPPORTING UPPER TROUGH DIGGING S INTO THE AREA WILL FOCUS BEST LIFT E OF 75W AS EMBEDDED VORT SHIFTS E AND SE NEXT 24 HOURS. STABLE ATMOSPHERIC CONDITIONS GENERALLY PREVAIL ELSEWHERE ACROSS THE AREA EXCEPT FOR RETROGRADING TUTT LOW ACROSS HISPANIOLA INDUCING MODEST NOCTURNAL CONVECTION ACROSS HAITI TO TURKS AND CAICOS. NELY FLOW AROUND 25 KT DEPICTED BY RECENT ASCAT PASS N OF FRONT OFF COAST AND INTO OFFSHORE WATERS OF THE CAROLINAS AND WILL GENERATE MODERATE PERIOD WIND SWELL THAT WILL AFFECT NW PORTIONS NEXT 36 HOURS WITH PEAK SEAS 6-8 FT MOVING INTO NE FLORIDA COASTAL AND OFFSHORE WATERS. OTHERWISE...WEAK RIDGE AXIS ALONG ABOUT 27N WILL WEAKEN FURTHER AS A SECONDARY BOUNDARY SINKS ALONG FAR NW PORTIONS TONIGHT AND MON...AND BOTH BOUNDARIES WEAKEN QUICKLY. THIS TO PRODUCE MODERATE ELY TRADES AROUND 15 KT S OF 22N AND LIGHT WINDS ELSEWHERE THROUGH MID WEEK. SAL OCCURRING N OF E CARIB TROPICAL WAVE TO MOVE W AND NW AND ACROSS SE HALF OF BAHAMAS BY TUE MORNING AND INTO EXTREME S FLORIDA AND MOST OF BAHAMAS BY WED NIGHT. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... GMZ011...NONE. GMZ013...NONE. GMZ015...NONE. GMZ017...NONE. GMZ019...NONE. GMZ021...NONE. GMZ023...NONE. GMZ025...NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... AMZ011...NONE. AMZ013...NONE. AMZ015...NONE. AMZ017...NONE. AMZ019...NONE. AMZ021...NONE. AMZ023...NONE. AMZ025...NONE. AMZ027...NONE. AMZ029...NONE. AMZ031...NONE. AMZ033...NONE. AMZ035...NONE. AMZ037...NONE. AMZ039...NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... AMZ111...NONE. AMZ113...NONE. AMZ115...NONE. AMZ117...NONE. AMZ119...NONE. AMZ121...NONE. AMZ123...NONE. AMZ125...NONE. AMZ127...NONE. *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANES.GOV/MARINE $$ .FORECASTER STRIPLING. NATIONAL HURRICANE CENTER.