000 AGXX40 KNHC 180829 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 430 AM EDT THU OCT 18 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC...AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... ANTICYCLONIC FLOW PREVAILS ACROSS MOST OF THE BASIN THIS MORNING IN ADVANCE OF COLD FRONT NEAR THE UPPER TEXAS COAST ATTM. MODERATE SLY RETURN FLOW NEAR 15 KT IS OBSERVED W OF 88W WITH SEAS GENERALLY 3-4 FT EXCEPT TO 5 FT ALONG S TEXAS COASTAL WATERS PER BUOY 42020. WEAK SURFACE LOW DEPICTED BY 0224Z ASCAT PASS OFF NW COAST OF CUBA...AND APPEARS ALONG REMNANTS OF OLD FRONTAL BOUNDARY ACROSS S FLORIDA INTERACTING WITH BASE OF UPPER TROUGH SWEEPING ACROSS THE GULF PAST 24 HOURS. KEY WEST RADAR SHOWING SCATTERED CONVECTION SHIFTING SLOWLY N AND NE ACROSS THE EXTREME SE GULF AND MODELS SUGGEST THIS WEATHER TO CONTINUE THROUGH MIDDAY BEFORE UPPER SUPPORT SHIFTS E AND SURFACE LOW BEGINS TO BECOME ELONGATED AND DRIFT WNW. COLD FRONT TO MOVE SE INTO COASTAL WATERS IN NEXT FEW HOURS WITH LLVL FLOW BECOMING DIFFLUENT AND FORCING MOISTURE E ACROSS NE GULF...FLORIDA AND INTO ATLC COASTAL WATERS...WHILE SOME MOISTURE QUICKLY RETURNS INTO CENTRAL TEXAS BY AFTERNOON. FRONT EXPECTED FRONT NEAR PENSACOLA TO CORPUS CHRISTI BY 00Z FRI AND THEN WEAKENING FROM JUST N OF TAMPA BAY TO JUST S OF CORPUS CHRISTI 00Z SAT. THERE IS SOME MODEST DIFFERENCE IN GLOBAL MODELS BEYOND THIS AND A REASONABLE CONSENSUS PUTS FRONTAL REMNANTS FROM EXTREME S TIP OF FLORIDA TO 24N90W THEN STATIONARY FRONT TO CENTRAL TEXAS COAST BY 00Z SUN. QUICKLY MOVING SUPPORTING UPPER TROUGH AND RESULTANT RAPID VEERING OF WINDS AT LLVL BEHIND THE BOUNDARY NOT ALLOWING FOR MUCH PRES GRADIENT AND WINDS EXPECTED BELOW 20 KT BEHIND FRONT TODAY AND TONIGHT...WITH STRONG WINDS LIKELY ACROSS NEAR SHORE COASTAL WATERS OF LA/MS TONIGHT. HIGH PRES TO THEN DOMINATE THE BASIN THROUGH THE WEEKEND WITH RETURN FLOW ACROSS W PORTIONS BY SAT AFTERNOON INCREASING TO 15-20 KT ALONG TEXAS COASTAL WATERS SUN...AND ENE 15-20 OFF N/NW COAST OF YUCATAN SAT EVENING AND SUN AFTERNOON/EVENING. WINDS TO INCREASE SLIGHTLY EARLY MON IN ADVANCE OF NEXT FRONTAL SYSTEM MOVING INTO GREAT PLAINS WITH SEAS 4-6 FT ACROSS MUCH OF W HALF OF BASIN AND ACROSS YUCATAN CHANNEL. SW N ATLC S OF 31N W OF 65W... UPPER TROUGH KICKING OFF SCATTERED MODERATE CONVECTION ALONG REMNANTS OF OLD FRONTAL ZONE ACROSS S FLORIDA AND NW BAHAMAS. TROUGH TO MOVE E WHILE MOISTURE IS SHUNTED NE DURING THE DAY. RIDGING THAT HAS BUILT ACROSS NW PORTIONS YIELDING SE WINDS 10-15 KT WITH SEAS 5-7 FT IN MIXED SE WINDSEA AND FADING NE SWELL FROM RAFAEL. WINDS WILL VEER SLY W OF 73W THIS MORNING IN ADVANCE OF GULFMEX COLD FRONT...THEN VEER FURTHER S TO SW THIS AFTERNOON. TROUGH EXTENDING SW FROM RAFAEL TO N OF HISPANIOLA PERSISTS THIS MORNING AND SLOWLY DRIFTING W...AND BLOCKING ATLC RIDGE FROM BUILDING STRONGLY INTO THE REGION. MOISTURE CONVERGENCE S OF 23N E OF BAHAMAS WILL GRADUALLY SHIFT W NEXT FEW DAYS TO MAINTAIN GOOD SHOWER CHANCES. OTHERWISE...WINDS 15 KT OR LESS AND SEAS SUBSIDING IN FADING NE RAFAEL SWELL NEXT 24 HOURS WITH COLD FRONT EXPECTED OFF N COAST OF FLORIDA BY 00Z SAT THEN SE FROM EXTREME S FLORIDA TO NEAR 31N74W BY 00Z. GFS SEEMS TO HAVE BEST HANDLE ON TROUGH TRAILING FROM RAFAEL AND PREFER ITS SOLUTION WITH GULF COLD FRONT AS WELL. HIGH PRES TO BUILD BEHIND FRONT SUN AND MON AND FRESHEN TO NEAR 20 KT ACROSS MUCH OF THE NW PART MON...BUILDING SEAS 5-7 FT. MODELS NOT IN AGREEMENT OF GRADIENT ACROSS THIS AREA SUN-MON DUE TO POSITIONING OF LOW PRES IN SW CARIB...AND CONFIDENCE STILL LOW WITH MONSOONAL LOW IN SW CARIB. ENSEMBLE MEANS INDICATING LOW TO REMAIN IN SW CARIB THROUGH MID WEEK. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... BROAD CYCLONIC LLVL FLOW ASSOCIATED WITH AN ACTIVE MONSOON FLOW IN EPAC AND SW CARIBBEAN CONTINUES TO PRODUCE GOOD MOISTURE CONVERGENCE ACROSS SW AND ERN CARIB...YIELDING SCATTERED SHOWERS AND TSTMS. LIGHT E TO SE SURFACE FLOW HAS RETURNED E OF 80W AND AIDING IN CONVERGENCE. LLVL TROUGH MOVING ACROSS WINDWARDS ATTM WILL SHIFT W NEXT FEW DAYS AND GRADUALLY WEAKEN ACROSS CENTRAL CARIB NEAR 70W BY SAT NIGHT. E TO SE WINDS 15-20 KT BEHIND THIS TROUGH WILL RAISE SEAS 4-5 FT...WITH WW3 A BIT SLOW IN RESPONDING TO THIS ENHANCED FLOW AND HAVE TRENDED MORE TOWARD ECWAVE MODEL. LLVL WIND SURGE ASSOCIATED WITH ILL DEFINED TROPICAL WAVE LIKELY NEAR 55W BRINGING AN INCREASE IN WINDS AND SEAS TO N TROPICAL ATLC WATERS THIS MORNING...WITH BUOY 41040 8 FT OVERNIGHT...AND THIS WIND AND WAVE FIELD TO SHIFT W TO WINDWARDS BY SUNSET TODAY. NEXT TROPICAL WAVE CURRENTLY ALONG 45/46W TO MOVE W INTO TROPICAL N ATLC WATERS SAT AFTERNOON AND PERTURB THE ITCZ FOR ACTIVE CONVECTION S PORTIONS. GLOBAL MODELS SOLUTIONS STILL TRYING TO RESOLVE MONSOON LOWS DEVELOPING ACROSS SW CARIB AND EPAC NEXT FEW DAYS AS POSITIVE PHASE OF MJO FORECAST TO MOVE THROUGH REGION DURING THE NEXT SEVERAL DAYS. GFS STILL INSISTENT ON SOME MODEST DEVELOPMENT IN THE EPAC...AS WELL AS A LOW IN THE SW CARIB...WHILE ECMWF SHOWING BROAD LOW ACROSS WRN CARIB. ENSEMBLE MEANS IN A LITTLE BETTER AGREEMENT THAN DETERMINISTIC MODELS THIS MORNING...BUT STILL UNCLEAR ATTM. IT APPEARS THAT LIGHT TO MODERATE WINDS AND SLIGHT SEAS WILL PREVAIL NEXT FEW DAYS ACROSS THE W CARIB WITH ACTIVE CONVECTION SW CARIB S OF 13N EXTENDING ENE INTO CENTRAL CARIB. MODERATE ELY TRADES TO RETURN TO TROPICAL ATLC BY MID WEEK. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .NONE. CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. SW N ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER STRIPLING