000 AGXX40 KNHC 281921 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 320 PM EDT FRI AUG 28 2009 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... A WEAK TROUGH EXTENDING FROM 30N85W TO NEAR 23N92W WILL SLOWLY MOVE E THIS AFTERNOON AND TONIGHT WHILE BECOMING DIFFUSE. SURFACE DATA AND A QSCAT PASS FROM THIS MORNING SHOWED VERY WELL THE WIND SHIFT ASSOCIATED WITH THIS TROUGH WHICH IS PRODUCING SCATTRED SHOWERS AND TSTMS OVER THE EASTERN GULF PARTICULARLY N N OF 26N AND E OF 84W. SCATTERED SHOWERS ARE ALSO NOTED ALONG THE TROUGH AXIS. HIGH PRES WILL BUILD ACROSS THE N GULF WATERS AS THE SFC TROUGH WEAKENS. THE RIDGE WILL SHIFT S AHEAD OF A COLD FRONT THAT IS EXPECTED TO MOVE INTO THE NORTHERN GULF SUN NIGHT. THE FRONT WILL REACH FROM THE FLORIDA PANHANDLE TO NEAR 26N92W MON MORNING BEFORE DISSIPATING ON TUE. N TO NE WINDS OF 15 KT AND SEAS OF UP TO 4 FT WILL FOLLOW THE FRONT. ELSEWHERE... MAINLY LIGHT AND VARIABLE WINDS AND SLIGHT SEAS WILL PREVAIL THROUGH THE PERIOD. CARIBBEAN AND TROPICAL N ATLC W OF 55W... A TROPICAL WAVE ALONG 84W WILL REACH THE YUCATAN PENINSULA SAT MORNING AND THE BAY OF CAMPECHE SUN MORNING WHERE IS EXPECTED TO SLIGHTLY INCREASE WINDS AND SEAS. QSCAT-HI DATA FROM THIS MORNING SHOWED NE TO E WINDS OF 20 TO 30 KT NEAR THE COAST OF COLOMBIA. THIS MODERATE TO STRONG FLOW IS ALLOWING SEAS TO BUILD TO 8 TO 12 FT THROUGH SAT...THEN DIMINISH SAT NIGHT AND SUN BEFORE REBUILDING BEHIND A SECOND TROPICAL WAVE...CURRENTLY ALONG 55W...EXPECTED TO MOVE ACROSS THE E CARIBBEAN ON SAT...CROSSING 70W BY SUN AND MOVING THROUGH THE WESTERN CARIBBEAN MON AND TUE. LOOKING AHEAD...A BROAD AREA OF LOW PRES LOCATED NEAR 10N38W CONTINUES TO PRODUCE DISORGANIZED SHOWERS AND THUNDERSTORMS. CONDITIONS APPEAR FAVORABLE FOR SLOW TROPICAL CYCLONE DEVELOPMENT OF THIS SYSTEM OVER THE NEXT COUPLE OF DAYS AS IT MOVES GENERALLY WESTWARD AT AROUND 10 KT. COMPUTER MODELS SUGGEST THAT THIS SYSTEM SHOULD BE NEARING THE TROPICAL N ATLC BY WED. SW N ATLC S OF 31N AND W OF 55W... AT 28/1500 UTC...TROPICAL STORM DANNY IS LOCATED NEAR 30.1N 75.5W MOVING TO THE NW AROUND 9 KT. A TIGHT PRES GRADIENT BETWEEN DANNY AND HIGH PRES OVER THE W ATLC IS ALLOWING THE STRONGEST WINDS TO REMAIN ON ITS E SIDE. DANNY IS FORECAST TO REMAIN AS A TROPICAL STORM WITH MAX SUSTAINED WINDS OF 4O KT MOVING INLAND IN ABOUT 48 HOURS. MAX SEAS OF 24 FT ARE EXPECTED MAINLY WITHIN 260 NM NE SEMICIRCLE OF DANNY SAT MORNING. A TROPICAL STORM WARNING REMAINS IN EFFECT OVER FORECAST WATERS N OF 28N BETWEEN 72W AND 76W. HOWEVER...TROPICAL STORM CONDITIONS ARE EXPECTED TO LIFT N OF AREA TONIGHT AS DANNY'S FORWARD SPEED INCREASES. AT 1800 UTC BUOYS 41010 AND 41047 WERE REPORTING SEAS TO 9 FT. MOST OF THE SHOWER AND TSTM ACTIVITY IS FOCUSED ON THE E AND SE SIDES OF THE STORM WITH THE LOW-LEVEL CENTER TOTALLY EXPOSED. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTPZ25 KNHC FOR MORE DETAILS ON DANNY. WARNINGS ATLC... .AMZ080...TROPICAL STORM WARNING N OF 28N BETWEEN 72W AND 76W... CARIBBEAN... .NONE. GULF OF MEXICO... .NONE $$ FORECASTER GR