000 AGXX40 KNHC 080630 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 230 AM EDT TUE MAY 08 2007 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. SW N ATLC... THE OCCLUDED AREA OF LOW PRES OFF THE GEORGIA/N FLORIDA COAST HAS CONTINUED TO WIND UP THROUGH THE DAY AND IS NOW CENTERED NEAR 31N76W AS IT DRIFTS WWD WITH A PRES OF 1001 MB. SOME CONVECTION HAS DEVELOPED IN A BAND WHICH CURLS ABOUT 100 NM AROUND THE NRN SEMICIRCLE...WITH THE MOST VIGOROUS TSTMS OCCURRING OVER THE GULF STREAM ACCORDING TO LIGHTNING DATA. A HIGH-RESOLUTION QUIKSCAT PASS AROUND 2354 UTC DEPICTS A NARROW SWATH OF 50-60 KT STORM FORCE WINDS LYING N OF 30N BETWEEN 77W AND 79W...AND GALES ELSEWHERE N OF 29N BETWEEN 75W AND 80W. MARGINAL GALES ARE ALSO OCCURRING E OF THE LOW CENTER. IF MODEL GUIDANCE IS RIGHT...THE SYSTEM IS PROBABLY AT ITS PEAK. FIRST THE WIND FORECAST. THE VARIOUS NUMERICAL MODELS APPEAR TO BE HAVING A HARD TIME INITIALIZING THE STRUCTURE OF THE LOW AS COMPARED WITH THE QUIKSCAT DATA. NONE OF THE MODELS SHOWS WIND MAXIMA NEAR 60 KT...THE CLOSEST BEING THE NAM WHICH IS SHOWING 50 KT. THE BEST PROXY FOR THE CURRENT WIND FIELD APPEARS TO BE GOING WITH THE 925 MB GFS WINDS. THE THINKING HERE IS THAT THERE IS ENOUGH INSTABILITY OVER THE GULF STREAM...WHERE SSTS ARE NEAR 80F...TO MIX DOWN STRONGER WINDS THAN WHAT IS BEING ADVERTISED BY THE MODELS. GIVEN THE USE OF THIS GUIDANCE... MAXIMUM WINDS OVER THE AREA W OF THE LOW SHOULD BE DOWN TO ABOUT 45 KT BY SUNRISE AS THE SYSTEM BEGINS TO WIND DOWN. THEREFORE WILL ALLOW THE STORM WARNING TO EXPIRE BY SUNRISE. WINDS ARE EXPECTED TO REMAIN GALE FORCE N OF 28N W OF 73W THROUGH THE DAY BUT SHOULD THEN DIMINISH BELOW WARNING CRITERIA TONIGHT. THE LOW IS EXPECTED TO DRIFT INLAND ACROSS GEORGIA OR N FLORIDA WED NIGHT AND THU WITH WINDS QUICKLY DIMINISHING. A LEFTOVER SURFACE TROUGH WILL EXTEND FROM E CUBA NE TO 30N72W THU AND THEN DRIFT E FROM E CUBA TO 30N65W BY SAT WITH HIGH PRES BUILDING IN NEAR 30N71W. NOW THE SEAS. NWW3 WAVE HEIGHTS AND BUOY OBSERVATIONS HAVE COME MORE IN LINE AND ARE ONLY ABOUT 1-2 FT DIFFERENT AT BUOYS 41009 AND 41010. THE MAIN DIFFERENCE IS WITH PERIODS. NWW3 IS SHOWING 11-12 SEC SWELLS MOVING SE/S TOWARDS FLORIDA AND THE BAHAMAS YET BOTH BUOYS ARE SHOWING CURRENT PERIODS RUNNING ABOUT 16 SEC. THE UKMET WAVE MODEL IS MORE IN LINE AT THE MOMENT WITH 15-17 SEC SWELLS EXTENDING N OF THE BAHAMAS. PERIODS SHOULD BEGIN DECREASING THROUGH THE DAY BUT THE UKMET STILL SHOWS 12-13 SEC WHICH WILL STILL POSE A SIGNIFICANT IMPACT ALONG THE FLORIDA/BAHAMAS COASTLINES. GULF OF MEXICO... THE DYING BACK DOOR COLD FRONT IS STILL NOTICEABLE EXTENDING FROM THE YUCATAN CHANNEL TO THE TEXAS/LOUISIANA BORDER CONTINUING TO PUSH SW. WINDS ARE NE/E 20 KT ACROSS MOST OF THE AREA BUT ARE EXPECTED TO DIMINISH THROUGH THE DAY AS HIGH PRES SETTLES IN. SEAS ARE TO 7 FT AT BUOYS 42003 AND 42001 BUT THEY TOO ARE EXPECTED TO DIMINISH THROUGH THE DAY TO 3-5 FT. CONDITIONS REMAIN RATHER BENIGN THROUGH SAT WITH HIGH PRES AND LIGHT WINDS DOMINATING THE REGION. CARIBBEAN AND TROPICAL N ATLC... A RELAXED GRADIENT LIES OVER THE CARIBBEAN DUE TO THE LOW OFF THE SE U.S. COAST...AND THE STRONGEST TRADES ARE LIMITED TO OFF THE VENEZUELAN COAST. VERY LITTLE CHANGE IS EXPECTED IN THE OVERALL PATTERN WITH WINDS EXPECTED TO REMAIN TO 20 KT OVER THE S/CENTRAL AND SE CARIBBEAN THROUGH SAT. WINDS WILL REMAIN MUCH LIGHTER OVER THE W CARIBBEAN AS WELL. WARNINGS... ATLANTIC... GALE WARNING...N OF 28N W OF 73W. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER BERG