000 AGXX40 KNHC 122008 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 304 PM EST FRI MAR 12 2010 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W GULF OF MEXICO... PRE FRONTAL TROUGH OUT AHEAD OF COLD FRONT EXTENDED FROM SE GULF SW TO YUCATAN PENINSULA. A LOW TO MID LEVEL IMPULSE MOVING ACROSS THE SE GULF AND OFFSHORE OF SW FLORIDA WILL CONTINUE TO INTERACT WITH A VERY MOIST AND UNSTABLE ENVIRONMENT AND GOOD DIVERGENCE ALOFT TO PRODUCE STRONG TO SEVERE TSTMS AHEAD OF THE FRONT MOVING SE AND S ACROSS THE WATERS E OF 85W THROUGH THIS EVENING. COLD FRONT BEHIND THIS EXTENDED FROM FLORIDA PANHANDLE TO BAY OF CAMPECHE WITH 20-30 KT NWLY FLOW BEHIND IT...BUT WILL BE SHORT LIVED AS HIGH PRES BUILDS DUE E ACROSS THE GULF AND WINDS BEGIN TO ABATE ACROSS THE W HALF OF THE GULF AFTER MIDNIGHT AND BECOME W TO NW ACROSS THE E HALF. HIGH PRES CENTER WILL THEN SHIFT INTO W CENTRAL GULF SAT AND SHIFT E ALONG 24N TO THE CENTRAL WATERS SUN ALLOWING WINDS AND SEAS TO ABATE FURTHER...WITH PEAK WINDS AND SEAS LINGERING NEAR 20 KT AND 6 FT ACROSS THE BIG BEND WATERS. A THIRD COLD FRONT WILL SWEEP E ACROSS THE NORTHERN WATERS TO THE N OF THE RIDGE FROM EARLY SAT THROUGH EARLY SUN. A POST FRONTAL RIDGE WILL DEVELOP MON FROM SW LA TO NW CUBA WITH THE HIGH PRES BUILDING MON THROUGH TUE RESULTING IN NLY WINDS INCREASING OVER MOST OF THE GULF TUE, TROPICAL ATLC AND CARIBBEAN SEA... UPPER LEVEL TROUGH MOVING SLOWLY E ALONG 50W HAS INDUCED A WAVE OR BROAD INVERTED TROUGH ALONG PERSISTENT FRONTAL TROUGH NEAR 21N AT 52/53W. BOUNDARY THEN EXTENDS W-SW INTO CARIB AS A SHEAR LINE AND HAS BECOME DIFFUSE IN PAST FEW HOURS AS FLOW HAS BECOME SELY IN ADVANCE OF DEEPENING LOW ALONG SE U.S. COAST. MODERATE TO FRESH E TO SE TRADES E OF 75W WILL PREVAIL THROUGH SUN EVENING AND THEN WEAKEN EXCEPT ACROSS THE FAR SRN CARIB MON AS FRONT DRAGS TO NE CARIB ISLANDS. S TO SWLY FLOW 20 TO 25 KT THIS MORNING ACROSS THE W AND NW CARIB HAS ALREADY BEGUN TO DIMINISH AHEAD OF APPROACHING FRONT. THE NEXT COLD FRONT WILL MOVE INTO YUCATAN CHANNEL EARLY TONIGHT...STALLING ALONG A PSN FROM WINDWARD PASSAGE TO HONDURAS BY SUN. THE SW EXTENSION OF FRONT WILL MOVE NW SUN NIGHT INTO MON WHILE THE SEGMENT N OF CARIBBEAN MOVES INTO TROPICAL WATERS NEAR 22N65W MON DISSECTING THE TROPICAL ATLC ZONE FROM 22N58W TO PUERTO RICO TUE. SW N ATLC... HIGH PRES CENTER CURRENTLY E OF BERMUDA WILL CONTINUE TO RETREAT E ALLOWING THE REINFORCED GULF COLD FRONT TO MOVE INTO W AND NW PORTIONS THIS EVENING. GFS GUIDANCE WAS FORECASTING A LLVL LOW TO DEVELOP N OF THE NW BAHAMAS TODAY AND MOVE NE INDUCING GALE FORCE SW TO S FLOW IN THE SE SEMICIRCLE OF THIS LOW. IT APPEARED INITIALLY TO BE A CONVECTIVE FEEDBACK ISSUE WITH THE MODEL...YET STLT IMAGERY SHOWED CNVTN DEVELOPING IN THIS AREA AND SHIFTING NE AND ASSOCIATED WITH SOME LLVL PERTURBATION. BASED ON THIS AND THE ECMWF SOLUTION I MOVED THE GALE WARNING FORWARD IN TIME TO 2100 UTC FOR THE AREA N OF 27N BETWEEN ABOUT 75W AND 65W. AS THE FRONT MOVES E AND SE ACROSS THE AREA DURING THE NEXT FEW DAYS...GALES ARE LIKELY TO CONTINUE IN A NARROW BAND E OF THE FRONT AND N OF 28N OR SO...THROUGH 36 HOURS...AND POSSIBLY A BIT LONGER. WILL WAIT TO EXAMINE THE LATEST MODEL RUNS BEFORE SHORTENING THE LENGTH OF THIS GALE WARNING. WLY FLOW FORECAST TO BUILD BEHIND THE FRONT AT 20 KT THROUGH SAT WITH A REINFORCING FRONTAL BOUNDARY MOVING E ACROSS FLORIDA SAT NIGHT-SUN MORNING AND TO ENHANCE THE FLOW TO 20-30 KT FROM THE SW AHEAD OF THIS NEW FRONT. THE FIRST COLD FRONT IS EXPECTED TO REACH FROM 31N67W TO WINDWARD PASSAGE SAT NIGHT... FROM 28N55W TO HISPANIOLA SUN NIGHT....AND FROM 24N55W TO MONA PASSAGE MON NIGHT...AND A FRONTAL TROUGH 22N55W TO VIRGIN ISLANDS TUE NIGHT. WARNINGS... ATLC... .AMZ080...GALE WARNING N OF 27N BETWEEN 75W AND 65W THIS EVENING. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER STRIPLING