000 AGXX40 KNHC 191803 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI JUN 19 2009 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. ATLC... THE MODELS ARE IN GOOD AGREEMENT ON THE DEVELOPMENT OF A HIGHLY AMPLIFIED PATTERN N OF 20N WITH A SLOW MOVING CUT OFF LOW OFF THE NORTHEAST U.S. COAST SUN THROUGH TUE BOOKENDED BY UPPER LEVEL RIDGING OVER THE CENTRAL N ATLC AND THE SOUTHERN PLAINS/LOWER MISSISSIPPI. WHILE CONFIDENCE IS LOW IN THE DETAILS...THERE IS REASONABLE AGREEMENT AMONG THE MODELS FOR THE COLD FRONT ASSOCIATED WITH THE NORTHEAST CUT OFF LOW TO MOVE INTO NW WATERS MON...BRINGING SOUTHWEST FLOW AHEAD OF THE FRONT TO 30 KT OVER FORECAST WATERS. CURRENTLY...THE SUBTROPICAL RIDGE IS WEAKENED AND SQUEEZED OVER THE CENTRAL/EASTERN ATLC BETWEEN THE BROAD WESTERN ATLC TROUGH AND A DEEP LAYER LOW WELL NORTH OF THE FORECAST AREA NEAR 32N20W. AS A RESULT...TRADE WINDS ARE LESS THAN 20 KT ACROSS THE TROPICAL N ATLC. EXPECT THE SUBTROPICAL HIGH TO REBUILD AND SHIFT WEST TO 45W ALONG 25-30N MON THROUGH TUE AS THE PATTERN BECOMES MORE AMPLIFIED...ALLOWING FOR THE RETURN OF FRESH TRADE WINDS IN THE TROPICAL N ATLC. THE SURFACE REFLECTION OF THE TROPICAL WAVE ALONG 43W S OF 08N IS EVIDENT IN THE 1254 UTC ASCAT PASS. JUST TO ITS EAST ALONG 36W LIES A MID LEVEL TROUGH WITH A WEAK SURFACE REFLECTION THAT APPEARS TO BE CATCHING UP WITH THE TROPICAL WAVE. THE MODELS DO A VERY POOR JOB DEPICTING THIS COMPLEX PATTERN INITIALLY...SO CONFIDENCE IS LOW IN THEIR FORECASTS. OFFICIAL FORECAST ALLOWS THE EASTERN VORTICITY CENTER TO MEET UP WITH THE TROPICAL WAVE AS IT APPROACHES THE CARIBBEAN. CARIBBEAN... THE AFOREMENTIONED TROPICAL WAVE WILL MOVE INTO THE EASTERN CARIBBEAN MON AND BEGIN TO LIFT NORTHWARD AS IT ENCOUNTERS THE LEADING EDGE OF A BUILDING BROAD TROUGH OVER THE WESTERN CARIBBEAN. THE HIGHLY AMPLIFIED DEEP LAYER TROUGHING ASSOCIATED WITH THE CUT OFF LOW OFF THE NORTHEAST U.S. COAST SUN THROUGH TUE WILL WEAKEN THE SUBTROPICAL RIDGE OVER THE BAHAMAS AND STRAITS OF FL AND ACT TO SLOW THE EASTERLY STEERING FLOW THROUGH THE CARIBBEAN. AS A RESULT...THE TROPICAL WAVE IS EXPECTED TO SLOW ITS WESTERLY PROGRESS BY THE END OF THE PERIOD. GULF OF MEXICO... HIGH PRES OVER THE N CENTRAL GULF WILL REMAIN IN CONTROL OF THE PATTERN THROUGH SAT...THEN WEAKEN AS IT SLIDES W INTO THE CENTRAL GULF EARLY NEXT WEEK AS A COLD FRONT ASSOCIATED WITH THE DEEP LAYER LOW IN THE WESTERN N ATLC PUSHES SOUTH INTO THE EASTERN GULF MON AND TUE. WARNINGS ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FORECASTER SCHAUER CLARK. TROPICAL PREDICTION CENTER.