000 AGXX40 KNHC 140809 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 305 AM EST MON DEC 14 2009 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W GULF OF MEXICO... LINGERING FRONTAL BOUNDARY DRAPED ACROSS THE NW AND N GULF PAST 24 HOURS HAS LIFTED N AND NW...AND WAS ACROSS THE NEAR SHORE COASTAL WATERS OF TEXAS AND LOUISIANA AND INTO THE COAST E OF MISSISSIPPI. MILD RETURN FLOW CURRENTLY DOMINATES THE GULF WITH A WEAK 1020 MB HIGH ALONG THE W COAST OF FLORIDA N OF TAMPA BAY. BKN-OVC LOW AND MID LEVEL CLOUDS WILL PREVAIL ACROSS THE FAR NW GULF THIS MORNING WITH LOW STRATUS AND FOG LIMITING VSBYS. THIS RETURN FLOW WILL INCREASE SLIGHTLY ACROSS S AND SW PORTIONS TODAY THROUGH THIS EVENING AS THE HIGH SHIFTS E AND ANOTHER COLD FRONT APPROACHES THE N GULF COASTS FROM THE NW. PEAKS WINDS AND SEAS ACROSS THE S HALF OF THE GULF WILL LIKELY REACH AROUND 15 KT AND 4-5 FT...EXCEPT 15-20 KT AND 5-6 FT THROUGH THE FLORIDA STRAITS. MODELS SUGGESTING THAT THIS NEXT FRONT WILL SINK INTO THE TEXAS AND SW LOUISIANA COASTAL WATERS LATE TUE AFTERNOON/EARLY EVENING AND THEN MERGE WITH CURRENT LINGERING FRONTAL REMNANTS AS THE NEW COLD FRONT SHIFTS SE ACROSS THE BASIN. FRONT IS FORECAST TO STRETCH FROM N CENTRAL FLORIDA TO E OF BROWNSVILLE EXTENDING S ALONG 96W INTO THE SW GULF BY WED MORNING...WITH STRONG NE 25 KT FLOW BUILDING BEHIND IT...PUMPING SEAS UP QUICKLY TO 12 FT OR GREATER ACROSS THE NW AND FAR W GULF DURING THE DAY WED. MODELS ARE THEN SUGGESTING THE DEVELOPMENT OF A SURFACE LOW OR SHARP TROUGH ALONG THE FRONT ACROSS THE NW GULF INVOF 25N95W THU IN RESPONSE TO A SRN STREAM MID-UPPER S/W MOVING ACROSS THE GULF. THE STRENGTH AND MOVEMENT OF THIS FEATURE WILL INFLUENCE THE PRES GRADIENT AND STRENGTH OF FLOW N AND W OF THE FRONT THU AND FRI...WITH SOME UNCERTAINTY STILL IN FORECAST DURING THIS PERIOD. THIS LOW OR TROUGH SHOULD EVENTUALLY MOVE E WITH UPPER FLOW AND ACROSS FLORIDA OVER THE UPCOMING WEEKEND AND INTO THE ATLC...WITH FRESH TO STRONG NW TO N FLOW AND COOL AIR SPILLING INTO THE W GULF BEHIND IT. ECMWF HAS BEEN MOST AGGRESSIVE IN DEVELOPING A SURFACE LOW OVER THE GULF...WHILE THE LATEST GFS DOES NOT INDICATE ANY SIGNIFICANT SURFACE DEVELOPMENT OF A LOW UNTIL THE S/W REACHES THE ATLC SAT-SUN. THIS MODEL DISAGREEMENT IS TO BE EXPECTED THROUGHOUT THE NEXT FEW MONTHS AS THE CURRENT WARM ENSO EVENT PERSISTS...AND ITS INDUCED ACTIVE SRN STREAM UPPER FLOW ACROSS THE GULF CONTINUES. CARIBBEAN AND TROPICAL N ATLC WATERS W OF 55W... GALE WARNING FOR SOUTHERN PORTION OF THE CARIBBEAN S OF 14N BETWEEN 72W AND 77W IS EXPECTED TO LAST THROUGH THIS AFTERNOON...BUT COULD VERY WELL PULSATE A LITTLE LONGER GIVEN THE STRONG GRADIENT BETWEEN RIDGING TO THE N OF THE AREA AND LOWER PRES OVER S AMERICA. RECENT ASCAT PASSES HAVE SAMPLED A SMALL PORTION OF THIS AREA AND HAVE INDICATED WINDS JUST UNDER GALE FORCE. THIS ILLUSTRATES THE UNCERTAINTY WE WILL HAVE TO LIVE WITH WITHOUT QUIKSCAT DATA. ELSEWHERE ACROSS THE CARIB...FRESH ELY TRADES OF 25-30 KT DOMINATE THE CENTRAL PORTION...AND 20-25 KT ACROSS THE E HALF EXTENDING INTO THE ATLC TO NEAR 55W. SEAS HAVE BUILT TO NEAR 16 FT IN THE SW CARIBBEAN OFF THE COAST OF COLOMBIA...AND WILL CHANGE LITTLE THROUGH TUE NIGHT BEFORE SLOWLY SUBSIDING. A WEAKENING ATLC HIGH PRES RIDGE TUE NIGHT THROUGH THU WILL BRING ABOUT A DECREASING TREND FROM E TO W ACROSS THE TROPICAL ATLC AND CARIB...WITH WINDS DROPPING BELOW 20 KT E OF 70W BY EARLY THU. LARGE N TO NW SWELL GENERATED ACROSS THE NW AND CENTRAL ATLC WILL DOMINATE SEAS ACROSS THE TROPICAL ATLC AND PROPAGATE THROUGH THE ATLC PASSAGES OF THE NE CARIBBEAN TODAY THROUGH EARLY WED BEFORE FADING....WITH PEAK SEAS ACROSS THE ATLC E OF THE LEEWARDS EXPECTED AT 10-12 FT THIS AFTERNOON THROUGH TONIGHT. SW N ATLC W OF 55W... LATEST SATELLITE IMAGERY SHOWS THE REMNANTS OF AN OLD COLD FRONT EXTENDING FROM THE CENTRAL ATLC WNW TO NEAR 23N70W...WITH RECENT ASCAT PASSES REVEALING A SHEAR LINE STRUCTURE WITH 25 KT WINDS N OF THE BOUNDARY...AND GENERALLY 20 KT TO THE S AND SW. WINDS ACROSS THE BAHAMAS AND FAR NW PORTIONS HAVE DROPPED CONSIDERABLY DURING THE PAST 24 HOURS...WITH SE TO S FLOW ACROSS THE BAHAMAS TURNING SW OFF THE COAST OF NE FLORIDA. SEAS ARE RUNNING 9-12 FT WITHIN A FEW DEGREES TO THE N OF THIS SHEAR LINE. PROGRESSIVE UPPER LEVEL FLOW WILL SHIFT THE PATTERN EWD NEXT 24-48 HOURS...WITH WEAKENING FLOW ACROSS THE AREA...AND SUBSIDING SEAS. NEXT FRONT TO SWEEP INTO THE GULF WILL DRAG ACROSS FAR NW PORTIONS TUE NIGHT AND SINK SE ACROSS THE N HALF OF THE AREA WED AND WED NIGHT...BRINGING FRESH N TO NELY FLOW AND BUILDING SEAS 8-12 FT BY THU MORNING IN NLY SWELL. AS MENTIONED IN GULFMEX SECTION...DEVELOPING LOW ACROSS THE GULF IS NOT FORECAST BY ALL MODELS...BUT A LOW IS EXPECTED TO INTENSIFY ACROSS THE W AND NW ATLC OVER THE UPCOMING WEEKEND AND COULD PRODUCE LARGE NLY SWELL MOVING INTO THE REGION EARLY THE FOLLOWING WEEK. WARNINGS... ATLC... NONE. CARIBBEAN... .AMZ084 AND AMZ086...GALE WARNING S OF 14N BETWEEN 72W AND 77W. GULF OF MEXICO... .NONE. $$ FORECASTER STRIPLING