000 AGXX40 KNHC 200724 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 330 AM EDT SAT JUN 20 2009 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. ATLC... A BROAD SURFACE RIDGE ALONG 26N IS BRINGING LIGHT WINDS TO MUCH OF THE DISCUSSION AREA AT PRESENT. HOWEVER...NE TO E TRADE WINDS OF 15 TO 20 KT COVER CENTRAL AND SOUTHERN PORTIONS OF THE TROPICAL N ATLC S OF THE RIDGE AXIS. AT THE SAME TIME...A WEAK FRONT ALONG 30N/31N BETWEEN 50W-57W IS BEING MAINTAINED BY A SERIES OF SHORTWAVE TROUGHS PROPAGATING THROUGH A MEAN UPPER LEVEL TROUGH N OF THE DISCUSSION AREA. THIS FRONT WILL SLOWLY WEAKEN DURING THE NEXT FEW DAYS AS THE BULK OF THE ASSOCIATED UPPER ENERGY LIFTS NORTHEAST OF THE REGION. HOWEVER... SURFACE PRES FALLS OVER THE CENTRAL ATLC DRIVEN BY ONE OF THE SHORTWAVES WILL STEEPEN THE PRES GRADIENT W OF THE RIDGE DURING THE NEXT DAY TO YIELD SW WINDS OF 20 TO 25 KT OVER FAR E PORTIONS OF THE DISCUSSION AREA ALONG WITH WITH SEAS TO 9 FT. THE MAIN FORECAST PROBLEM COMES LATE IN THE WEEKEND INTO EARLY NEXT WEEK...WHEN A SHORTWAVE TROUGH CURRENTLY OVER THE UPPER MIDWEST QUICKLY DIVES EAST-SOUTHEASTWARD...APPROACHING THE MID-ATLANTIC STATES BY EARLY SUN. AN UPPER LEVEL JET MAXIMUM DIVING TOWARD THE UPPER TROUGH AXIS WILL SERVE TO AMPLIFY IT OFF THE E COAST BY LATE THIS WEEKEND. A DEEPENING SURFACE LOW WILL THEN PUSH OFF THE E COAST EARLY SUN...WITH A WEAKENING COLD FRONT ENTERING THE NORTHERN WATERS ON MON. GLOBAL MODELS AGREE FOR THE MOST PART ON THE LOCATION OF THE SURFACE LOW AND FRONT...WITH SOUTHWEST WINDS INCREASING TO 20-30 KT AHEAD OF THE FRONT LATE THIS WEEKEND AND EARLY NEXT WEEK. AS THE AFOREMENTIONED UPPER TROUGH CUTS OFF FROM UPPER LEVEL JET SUPPORT EARLY NEXT WEEK...THE SURFACE FRONT WILL WEAKEN...THOUGH THE BROAD TRAILING SURFACE TROUGH WILL YIELD SUFFICIENTLY STRONG GRADIENT FLOW W OF A BUILDING HIGH OVER THE CENTRAL ATLC TO MAINTAIN 20-30 KT WINDS E OF THE TROUGH INTO WED. MAX SEAS TO 13 FT WILL LIKELY RESULT. SOME POTENTIAL EXISTS FOR A WEAK SURFACE LOW TO SPIN UP ON THE TRAILING TROUGH AXIS NEAR THE BAHAMAS BY THE MIDDLE OF NEXT WEEK...THOUGH CONFIDENCE IN THIS SCENARIO IS RATHER LIMITED. ALSO...THE LOW AMPLITUDE TROPICAL WAVE ALONG 44W S OF 9N WAS EVIDENT IN THE 19/2045 UTC QUIKSCAT PASS...AND IS BEING WELL-RESOLVED BY BOTH THE ECMWF AND GFS. BOTH MODELS CARRY THIS PERTURBATION WESTWARD AROUND 10-12 KT DURING THE NEXT FEW DAYS WHILE WEAKENING IT AS IT INTERACTS WITH HIGHER TERRAIN OVER NORTHERN PORTIONS OF SOUTH AMERICA. CARIBBEAN... E WINDS OF 15 TO 20 KT COVER MUCH OF THE CARIBBEAN AT PRESENT... WITH THE STRONGEST WINDS FOUND NEAR THE COAST OF COLOMBIA. THIS RELATIVE WEAKNESS IN THE TRADE WINDS IS BEING SUPPORTED BY MEAN SURFACE TROUGHING N OF THE AREA. THE AFOREMENTIONED TROPICAL WAVE 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 EARLY NEXT WEEK...WITH THE REMNANTS OF THE TROPICAL WAVE BEING STEERED NORTHWESTWARD AS IT MOVES ACROSS THE CARIBBEAN NEXT WEEK. WEAKER LOW LEVEL FLOW NEAR THE BROAD SURFACE TROUGH WILL SLOW THE WAVE/S MOTION BY THE MIDDLE OF NEXT WEEK. A BUILDING SUBTROPICAL RIDGE OVER THE CENTRAL ATLC WILL MAINTAIN MODERATE TO FRESH TRADE WINDS ACROSS THE E CARIBBEAN NEXT WEEK. GULF OF MEXICO... SURFACE HIGH PRES OVER THE N CENTRAL GULF WILL AFFECT MUCH OF THE GULF INTO EARLY NEXT WEEK...WHILE DRIFTING WESTWARD. THIS WILL STEEPEN THE PRESSURE GRADIENT BETWEEN THE HIGH AND A BROAD TROUGH OVER MEXICO TO DRIVE E TO SE WINDS UP TO 20 KT ACROSS THE BAY OF CAMPECHE FOR THE MIDDLE OF NEXT WEEK. ALSO...A COLD FRONT ASSOCIATED WITH THE DEEP LAYER LOW IN THE WESTERN N ATLC WILL PUSH SOUTHWARD INTO THE EASTERN GULF MON AND TUE. NW WINDS UP TO 20 KT WILL ALSO FOLLOW THE FRONT OVER THE E GULF. WARNINGS ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FORECASTER COHEN. TROPICAL PREDICTION CENTER.