000 AGXX40 KNHC 241857 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 300 PM EDT SUN MAY 24 2009 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... WEAK PRESSURE PATTERN IN THE WAKE OF LOW PRESSURE...NOW CENTERED OVER ARKANSAS...IS ALLOWING FOR GENERALLY LIGHT S TO SW FLOW ACROSS THE GULF. SEAS ARE GENERALLY IN THE 1-3 FT RANGE...EXCEPT NEAR THE W FLORIDA PANHANDLE WHERE RESIDUAL SWELL IS KEEPING SEAS TO 4 FT. HOWEVER...HIGHER WIND GUSTS ARE LIKELY IN SCATTERED TSTMS ACROSS THE N HALF OF THE REGION. THIS TSTM ACTIVITY IS ASSOCIATED WITH A TRAILING SFC TROUGH AND A WEAK MID-UPPER DISTURBANCE TRACKING E ACROSS THE AREA. WEAK RIDGING WILL BUILD W FROM CENTRAL FLORIDA TO THE WESTERN BAY OF CAMPECHE TONIGHT AND MON. THE PRES GRADIENT BETWEEN THE RIDGE AND LOW PRES OVER TEXAS/MEXICO WILL INCREASE SLY RETURN FLOW TO 15-20 KT OVER THE FAR W WATERS LATE MON THROUGH THU. WINDS WILL REMAIN LIGHT ELSEWHERE. BY LATE THU AND FRI...MUCH OF THE MODEL GUIDANCE IS DRAGGING A WEAK FRONT OR TROUGH INTO THE NW WATERS WHICH SHOULD ALLOW THE PRES GRADIENT OVER THE NW WATERS TO WEAKEN. CARIBBEAN AND TROPICAL ATLC W OF 55W... PRESSURE GRADIENT BETWEEN HIGH PRES NE OF BERMUDA NEAR 35N60W AND LOWER PRESSURE OVER SOUTH AMERICA IS PRODUCING A SWATH OF 20-25 KT TRADE WINDS OVER THE SE CARIBBEAN AND 15-20 KT ACROSS MUCH OF THE REMAINDER OF THE ERN ZONE. ELSEWHERE IN THE WESTERN CARIBBEAN AND OVER ATLC WATERS BETWEEN 55W AND THE ISLANDS... TROUGHS TO THE NORTH OF THESE RESPECTIVE AREAS ARE MAINTAINING ONLY 10-15 KT FLOW. LITTLE CHANGE IS ANTICIPATED OVER THE NEXT COUPLE OF DAYS. WINDS WILL START TO INCREASE EAST OF THE WINDWARDS BY WED AS THE TROUGHING TO THE NORTH BREAKS DOWN AND THE ATLC RIDGE BUILDS SW. SIMILARLY...WINDS WILL PICK UP SLIGHTLY OVER THE NW CARIBBEAN BY MIDWEEK AS THE RIDGE BUILDS OVER THE GULF OF MEXICO. SUBTROPICAL ATLANTIC W OF 55W... WINDS CONTINUE TO DIMINISH OVER THE W ATLC...KEPT 15-20 KT IN THE INITIAL BUT MAY BE FALLING BELOW THAT BASED ON BUOY REPORTS OFF THE NE FLORIDA COAST. SEAS ARE STILL 5-7 FT IN SE SWELL NE OF THE BAHAMAS. THE FORECAST REMAINS CHALLENGING OVER THIS AREA AS THE MODEL SPREAD REMAINS. GFS HAS BEEN CONSISTENT IN SHOWING LOW PRESSURE DEVELOP OVER OR NEAR THE BAHAMAS DURING THE PAST COUPLE OF DAYS WITH THE LATEST RUN SHOWING THE LOW/TROUGH DEVELOPING TONIGHT. TO THIS POINT...THE MODEL HAS BEEN INCORRECT IN DOING SO. NOGAPS HAS GENERALLY JOINED THE GFS IN SHOWING THIS FEATURE DEVELOP TONIGHT. THE UKMET...ECMWF...AND GFS ENSEMBLE MEAN ARE LESS AGGRESSIVE SUGGESTING BROAD E-W TROUGHING TO DEVELOP ON MON AND LIFT N-NE. THE LATTER SOLUTION IS PREFERRED...THOUGH WE ARE FORECASTING SLIGHTLY HIGHER WINDS THAN DIRECT MODEL OUTPUT TO ACCOUNT FOR A LITTLE MORE OF AN ORGANIZED TROUGH. THE GRADIENT FLOW SHOULD BE ENOUGH TO PRODUCE 15-20 KT FLOW EVEN IF ONLY A WEAK TROUGH DEVELOPS. ACCORDINGLY...LOWERED WAVE HEIGHTS FROM WW3 OUTPUT. THE TROUGH/LOW SHOULD EXIT THE AREA BY THE END OF THE WEEK WITH HIGH PRES RIDGING BUILDING ACROSS THE ZONE. WARNINGS ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FORECASTER CANGIALOSI. TROPICAL PREDICTION CENTER.