000 AGXX40 KNHC 150544 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 145 AM EDT TUE APR 15 2008 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. UPPER LEVEL LONGWAVE TROUGH BRINGS A TOUCH OF VERY DRY MODIFIED POLAR AIR MASS INTO SRN LATITUDES...NOT VERY COMMON FOR MID APRIL. TROUGH FLATTENS WEAK ANTICYCLONE ALOFT OVER NICARAGUA CUTTING OFF FLOW OF MOISTURE INTO SW N ATLC COLD FRONT AND RENDERING IT ALMOST A RAINLESS BOUNDARY. ANTICYCLONE HAS RIDGE EXTEND TO SECOND GYRE AT 30N50W WITH A SWATH OF MODERATE TO STRONG SUBSIDENCE WHICH COVERS MOST OF SW N ATLC AND ENTIRE CARIBBEAN BASIN. GULF OF MEXICO... N WINDS DIMINISHING AND VEERING NE-E AS HEALTHY HIGH PRES MOVES SE OVER FLORIDA PENINSULA. SE-S RETURN FLOW OVER NW WATERS EXPECTED TO INCREASE WED NIGHT AND SPREAD TO W OF 90W THU AND FRI AS NEXT COLD FRONT ENTER TX GULF COAST. SW N ATLC... LOW PRES NEAR 30N77W ALONG INITIAL FRONTAL BOUNDARY. COLD AIR SURGE OFF N FL COAST EXPECTED TO MERGE WITH FRONTAL BOUNDARY AS LOW PRES MOVES N OF 31N NEAR 73W EARLY TODAY DRAGGING SURGE OF COLD AIR INTO SW ATLC WATERS W OF 70W THROUGH THU. STRONG COLD N WIND EXPECTED TO REACH GALE FORCE N OF 28N W OF 77W TONIGHT. WARM GULF STREAM WATERS OPPOSITE WIND SURGE EXPECTED TO BE ABOVE 15 FT. AS A MATTER OF FACT...NWW3 15/00Z RUN RAISED ITS SOLUTION TO 17 FT FROM YESTERDAYS 12-13 FT CLEARLY SHOWING A BETTER HANDLE ON SITUATION. COLD AIR WILL MOVE E OF 65W THU NIGHT AS RIDGE BUILDS ALONG 29-30N FRI AND THEN SHIFTS N OF 31N SAT. CARIBBEAN AND TROPICAL NORTH ATLANTIC... DIFFERENCES IN MODEL OUTPUT FOR WINDS ALONG COAST OF COLOMBIA VARY AS THEY DIFFER IN STRENGTH OF LOW PRES OVER NW SOUTH AMERICA. WEAKENING COLD FRONT OVER NW CARIBBEAN WILL INCH SE AND EASE GRADIENT DIMINISHING THESE WINDS TODAY...BUT HIGH PRES MOVES INTO SW N ATLC TIGHTENING GRADIENT AGAIN INCREASING WINDS S OF 17N W OF 70W. LONG FETCH OF STEADY MODERATE TRADES OVER ATLC WILL BUILD SEAS OVER TRPCL ATLC THROUGH THU. ATLC HIGH PRES FORCED BY LOW PRES MENTIONED ABOVE TO MOVE E WILL DECREASE WIND FLOW AFTER THU. WARNINGS... ATLC... GALE WARNING N OF 28N W OF 77W...AMZ080. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER WALLY BARNES