000 AGXX40 KNHC 191841 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 240 PM EDT WED SEP 19 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... OLD FRONTAL ZONE CONTINUES TODAY FROM N FLORIDA SW TO CENTRAL BAY OF CAMPECHE...WITH N PORTIONS ACTUALLY DRIFTING SE THIS MORNING AS A REINFORCING FRONTAL TROUGH HAS SWEPT INTO THE N GULF. STRONG DOWNSTREAM BLOCKING PATTERN ACROSS MOST OF THE ATLC WILL MAINTAIN BROAD U.S. UPPER TROUGH AND NOT ALLOW ANY SIGNIFICANT SUPPORT TO MOVE BOUNDARY OVER THE NEXT FEW DAYS. THUS LOOK FOR THE BOUNDARY TO GRADUALLY WASH OUT IN THE NEXT 2-3 DAYS...WITH TROUGHING CONTINUING IN THE SW GULF/BAY OF CAMPECHE...MEANDERING BACK AND FORTH AS DIURNALLY FORCED YUCATAN TROUGH MOVES W AND OVER WATER EACH EVENING. SEAS TO CONTINUE 2-4 FT NEAR FRONTAL ZONE THROUGH THIS EVENING...EXCEPT FOR LOWER MEXICAN COAST WHERE NLY FLOW WILL MAINTAIN SEAS 3-4 FT NEXT COUPLE OF DAYS. OTHERWISE...MODERATE WINDS AND MILD SEAS TO PREVAIL. ELY FLOW TO NEAR 15 KT IS FORECAST TO RETURN N OF 24N BY LATE SUN EARLY MON AS HIGH PRES BUILDS ACROSS NRN GULF AND ERN U.S. SOUTHWEST NORTH ATLC S OF 31N W OF 55W... LITTLE CHANGE IN OVERALL UPPER PATTERN OVER MOST OF THE BASIN N OF 20N NEXT FEW DAYS. MID ATLC TROUGH ALONG 52W AND ASSOCIATED LLVL CENTER(S) WILL ALLOW RIDGING FROM NW ATLC TO CONTINUE SW INTO THE AREA...TO PRODUCE LIGHT TO MODERATE ANTICYCLONIC FLOW ACROSS THE AREA N OF 22N. WEAK FRONTAL BOUNDARY IS PUSHING OFF THE NE FLORIDA AND SC COASTS ATTM BUT WILL BECOME STRUNG OUT AND LOSE IDENTITY ACROSS THE LOCAL WATERS THROUGH FRI AS DEEP LAYER FLOW REMAINS NEARLY PARALLEL TO FRONT. LAST SIGNIFICANT PULSE OF NE SWELL FROM NADINE IS FADING ACROSS THE ATLC WATERS OF THE ANTILLES AND WILL END THIS EVENING. THERE IS CHANCE FOR ADDITIONAL NE SWELL FROM PAST TROPICAL NADINE OVER THE WEEKEND...DEPENDING ON MOTION AND TRAJECTORY. DEVELOPING SURFACE LOW HAS SHORT WINDOW (48-60 HRS) TO DEEPEN AND PRODUCE ANY SIGNIFICANT WAVE ENERGY FOR THE AREA E OF 65W...AND IS NOT CURRENTLY SUGGESTED BY GLOBAL MODELS. HAVE USED A BLEND OF ENSEMBLE MEANS FOR POSITION OF THIS SURFACE LOW THROUGH 72 HRS. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... WIND AND SEAS ACROSS CARIB BASIN ABOUT AS TRANQUIL AS ONE WILL FIND THIS MORNING...WITH SEAS LESS THAN 4 FT AT 12Z...EXCEPT POSSIBLY IN GULF OF HONDURAS WHERE SEAS TO 5 FT FORECAST BY WW3. TROPICAL WAVE MOVING W THROUGH CENTRAL CARIB ATTM...WITH TRAILING ZONE OF MOISTURE CONVERGENCE AFFECTING THE BASIN N OF 15N...WITH ACTIVE CONVECTION EXPECTED ACROSS HISPANIOLA AND JAMAICA AND ADJACENT WATERS THROUGH THU MORNING. WAVE TO REACH THE YUCATAN LATE FRI-EARLY SAT. LIGHT TO MODERATE WINDS AND MILD SEAS TO CONTINUE THROUGH EARLY FRI BEFORE MODERATE TRADES 15-20 KT BEGIN TO RETURN TO THE SRN CARIB...INCREASING TO 20-25 KT BY LATE SAT. NEXT TROPICAL WAVE ACROSS W CENTRAL ATLC GRADUALLY BECOMING STRETCHED AND ELONGATED DUE TO CENTRAL ATLC UPPER TROUGH...AND WILL TAKE A MORE NW MOTION FRI AND SAT AS IT ENCOUNTERS A SE DEEP LAYERED FLOW. LITTLE IMPACTS FROM WINDS FROM THIS WAVE FOR THE TROPICAL N ATLC WATERS...BUT ASSOCIATED CONVECTION WILL GRADUALLY SHIFT WNW THEN NW...AND INTO NE PORTIONS LATE THU...N PORTIONS ON FRI...AND SKIRT THE NE CARIB ISLANDS AND ATLC WATERS SAT. 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