000 AGXX40 KNHC 221826 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 300 PM EDT MON JUN 22 2009 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. SW N ATLC... VERY LITTLE CHANGE IN REASONING FROM THE PREVIOUS DISCUSSION BASED ON THE LATEST MODEL GUIDANCE. THE MAIN FCST ISSUE REMAINS THE EVOLUTION OF THE EXPECTED SWATH OF STRONG SLY WINDS OVER THE FAR NE PORTIONS OF THE ZONE FOR TUE INTO WED. ALL MODELS LATCH UNTO A STRONG VORT MAX CURRENTLY OVER THE EASTERN MID ATLC STATES WHICH IS FCST TO DIVE SWD ON THE W SIDE OF THE ANOMALOUSLY DEEP TROUGH JUST OFF THE E COAST. A SFC LOW IS EXPECTED TO DEVELOP OVERNIGHT TONIGHT ALONG AN EXISTING COLD FRONT OVER THE N CENTRAL PORTION OF THE ZONE AND MOVES ACROSS 31N BETWEEN 68W AND 70W...DEPENDING ON THE MODEL OF CHOICE. THERE IS CONTINUED CONFIDENCE THAT THERE WILL NOT BE SUSTAINED GALE FORCE WINDS OVER FORECAST WATERS IN THE ZONE ON TUE GIVEN THE OUTPUT FROM THE 12Z MODELS. THE 12Z GFS BRIEFLY SHOWS WINDS TO 35 KT ON THE EASTERN SIDE OF THE DEVELOPING SURFACE LOW OVERNIGHT...BUT THERE IS LITTLE SUPPORT FROM THE ENSEMBLES WITH THE SREF CURRENTLY SHOWING LESS THAN A 5 PERCENT CHANCE OF GALES. IN ADDITION...THE 12Z GFS GENERATES OVER 5.50 INCHES OF RAIN WITH THE DEVELOPING LOW AROUND THE SAME TIME...A LIKELY SIGN OF GRID-SCALE FEEDBACK. THUS WILL FCST 20-30 KT WINDS WITH HIGHER GUSTS THIS PACKAGE. IN ADDITION...THE MODELS DEVELOP ANOTHER WAVE DEVELOPING FURTHER S ALONG THE TROUGH ON WED WITH A ANOTHER SURGE OF WINDS. DETAILS OF THE ULTIMATE EVOLUTION OF THE WIND FIELD ARE HIGHLY RELIANT UPON THE SPEED...INTENSITY...AND TRACK OF THE SHORTWAVE ENERGY DROPPING SOUTH ALONG THE BACKSIDE OF THIS AMPLIFIED TROUGH THROUGH THE EASTERN U.S...SOMETHING THE MODELS RARELY HANDLE WELL...BUT THE CURRENT TREND WOULD SUPPORT A BROADENED TROUGH WITH MOVING MULTIPLE SHORTWAVE SYSTEMS PASSING QUICKLY THROUGH THE BASE OF THE TROUGH...MAKING ANY SIGNIFICANT SURFACE DEVELOPMENT LESS LIKELY...AND HENCE ANY SUSTAINED GALE FORCE WINDS. CARIBBEAN... QUIKSCAT PASS FROM 1014 UTC INDICATED WINDS ABOVE 20 KT WERE LIMITED TO S OF 14N W OF 70W. THE TROPICAL WAVE CURRENTLY ALONG 57W AND S OF 14N WILL MOVE INTO THE EASTERN CARIBBEAN TUE. AT THE SAME TIME...THE DEEPENING SURFACE TROUGH OVER THE SW NORTH ATLC WILL VEER WINDS OVER THE E CARIBBEAN TO MORE SOUTHEASTERLY AND POSSIBLY STEER THE WAVE NORTHWESTWARD AS IT MOVES ACROSS THE CENTRAL AND WESTERN CARIBBEAN. ON THU AND FRI A BUILDING SUBTROPICAL RIDGE OVER THE CENTRAL ATLC WILL INTRODUCE MODERATE TO FRESH TRADE WINDS ACROSS THE E AND CENTRAL CARIBBEAN. GULF OF MEXICO... LOW PRES TROUGH IN THE SW GULF IN BRINGING SE FLOW ABOVE 20 KT ON ITS EASTERN SIDE...WITH WINDS AND SEAS HIGHER WITHIN THE SCATTERED TSTMS W OF 93W S OF 24N. THE TROUGH WILL DISSIPATE ON WED AS IT DRIFTS W. SURFACE HIGH PRES OVER THE N CENTRAL GULF WILL DRIFT WESTWARD THROUGH THE WEEK. AS THE HIGH DRIFTS WEST...WINDS WILL BECOME NW AT 15 TO 20 KT TUE AND WED IN RESPONSE TO THE DEEPENING LAYER LOW IN THE WESTERN N ATLC. RIDGE BUILDS WWD OVER THE GULF ALONG 25N THU AND FRI. WARNINGS ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FORECASTER SCHAUER CLARK. TROPICAL PREDICTION CENTER.