000 AGXX40 KNHC 071846 RRA MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 300 PM EDT THU MAY O7 2009 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... AN E TO W RIDGE WILL PERSIST ACROSS THE NORTHERN GULF WATERS THROUGH SAT. IT WILL RETRACT E TO THE CENTRAL WATERS ALLOWING A WEAK COLD FRONT TO ENTER THE NW GULF MON...MOVING TO ALONG 29N MON NIGHT. THE MODELS VARY WITH THE TIMING OF THIS COLD FRONT AND ITS LATITUDE...WITH THE GFS AND ECMWF IN REASONABLE AGREEMENT WHILE THE UKMET IS FASTER/MORE SOUTHERLY AND THE NOGAPS IS LESS AMPLIFIED AND FARTHER N. THE MIDDLE OF THE ROAD GFS SEEMS ACCEPTABLE HERE. THE REMAINDER FORECAST AREA...EXPECT VARIABLE WINDS TO 10 KT RIGHT ALONG THE RIDGE AXIS...AND AROUND THE OCCASIONAL WEAK HIGH CENTER THAT WILL FORM ALONG THE RIDGE AXIS OVER THE NE GULF. STRONGEST WINDS WILL REMAIN IN THE WESTERN GULF THROUGH THE WEEKEND BEFORE THE FRONT COMES INTO PLAY. SW N ATLC... A BROAD LOW LEVEL TROUGH CURRENTLY DRIFTING W OVER THE WATERS BETWEEN 73W AND 76W IS EXPECTED TO PERSIST UNTIL LATE FRI WHEN A WEAK UPPER MOVES OFF THE MID ATL/SOUTHEAST U.S. COAST AND SHEARS THE UPPER SUPPORT FOR THE SYSTEM OFF TO THE NORTH. CONTINUED TO MENTION A REFLECTED TROUGH AT THE SURFACE THROUGH FRI OVER THE CENTRAL BAHAMAS. SHOWERS CAN BE FOUND NEAR THE TROUGH AXIS. STRONGER CONVECTION HAS FLARED MAINLY NEAR THE NORTH EDGE OF THE TROUGH...COINCIDING WITH THE MID LEVEL VORTICITY CENTER. THIS AREA OF STRONGER CONVECTION SHOULD LIFT NORTHWARD AS THE VORTICITY CENTER MOVES INTO THE LEADING EDGE OF THE TROUGH. THE RIDGE AXIS IS EXPECTED TO BUILD IN AS THIS TROUGH DISSIPATES...AND WILL LIE E TO W ALONG 27N OVER THE WEEKEND AND THEN SHIFT BACK N TO ALONG 28N MON. THE MODELS ARE IN GOOD AGREEMENT WITH THIS SCENARIO UNTIL MON WHEN THE NOGAPS HOLDS STRONGER RIDGING FARTHER N OF THE BAHAMAS THAN THE OTHER MODELS...ESPECIALLY THE UKMET. THE GFS APPEARS ACCEPTABLE HERE. CARIBBEAN AND TROPICAL N ATLC... A BROAD LOW LEVEL TROUGH OVER THE NORTH CENTRAL CARIBBEAN IN THE VICINITY OF THE WINDWARD PASSAGE SHOULD BECOME DIFFUSE TONIGHT. THE FRESH E TRADE WINDS OVER THE AREA GENERALLY E OF 70W ARE EXPECTED TO SPREAD W ACROSS MOST THE AREA AS THE ATLC RIDGE SHIFTS S AND LIES E TO W ALONG 27N TO 28N THROUGH MON. 20 KT WINDS IN THE GULF OF HONDURAS ARE EXPECTED TO PERSIST THROUGH THE PERIOD...EXPANDING EASTWARD AS THEY MEET UP WITH THE TRADES OVER THE WEEKEND. THESE STRONG WINDS ARE ATTRIBUTABLE TO THE PRESSURE GRADIENT BETWEEN THE RIDGE WELL TO THE NE AND TROUGHING OVER EASTERN/CENTRAL MEXICO. EASTERLY WINDS TO THE LEE OF CUBA WILL REMAIN AT 10 TO 15 KT THROUGH THE PERIOD. THE LOCALLY ENHANCED WIND AND SEAS CONDITIONS ALONG THE COAST OF COLOMBIA HAVE RETURNED AND ARE EXPECTED TO PERSIST THROUGH THE PERIOD. ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FORECASTER SCHAUER CLARK. TROPICAL PREDICTION CENTER.