000 AGXX40 KNHC 200517 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 130 AM EDT MON AUG 20 2007 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. AT MID LEVELS TONIGHT A BUBBLE OF HIGH PRES IS CENTERED JUST OFF THE SE COAST. AN UPPER LOW WAS OVER THE W CENTRAL GULF MOVING W 10 KT. A MID LEVEL INVERTED TROUGH WAS ALONG 60W ASSOCIATED WITH A TRPL WAVE. THE WESTERLIES WERE CONFINED TO MOSTLY N OF OUR REGION BUT DIP TO 32N ALONG 57W TONIGHT AS A STRONG LARGE TROUGH SWINGS SE OFF THE CANADIAN MARITIMES. ON THE SURFACE TONIGHT THE MAIN EVENT IS HRCN DEAN MOVING W AT 17 KT AND CURRENTLY A STRONG CAT 4. THE STORM IS A COMPACT VERY STRONG TRPL CYCLONE AND THE WARNING AREA IS STRICTLY THE WRN CARIBBEAN ZONE. THE ATLC RIDGE IS CENTERED OVER MID OCEAN WITH AN AXIS EXTENDING W ALONG 31N TO THE SRN CONUS. A MODERATE TRPL WAVE WAS ALONG 58W WITH A WEAK LOW NEAR 13N55W AT 00Z. THERE ARE INDCATIONS FROM LATEST SATELLITE IMAGERY THAT ANOTHER CENTER MAY BE FORMING IN THE NRN PORTION OF THE WAVE NEAR 20N. WINDS ARE BRISK OVER MUCH OF THE AREA E OF 90W DUE TO THE PRESENCE OF DEAN AND THE MODERATE ATLC RIDGE. LATER DAY 1 MID LEVEL RIDGING HOLDS ON ALONG 30N WITH THE INVERTED TROUGH MOVING W ALONG 62W. THE UPPER LOW IN THE W CENTRAL GULF CONTNUES WWD. ON THE SURFACE HRCN DEAN CONTINUES WWD TOWARD THE YUCATAN PENINSULA. FOR DAY 2 THE MID LEVEL RIDGE ALONG 30N ACTUALLY STRENGTHENS WITH A NEW CENTER HOLDING NEAR 31N82W. THE RIDGE WILL EXTEND E TO 30N40W. THE INVERTED TROUGH MOVES W TO 70W WHILE THE MID LEVEL LOW OVER THE GULF MOVES INLAND OVER NE MEXICO. ON THE SURFACE DAY 2 HRCN DEAN CROSSES YUCATAN AND EMERGES ON THE GULF SIDE NEAR 20N90W. WHILE WEAKER..STILL A MAJOR CONCERN TO MARINE INTERESTS OVER THE SRN GULF. THE ATLC RIDGE CENTER 1025 MB SHOULD BE NEAR 32N46W WITH THE AXIS REMAINING ALONG 32N WWD OVER THE SRN CONUS. WINDS OVER THE ENTIRE AREA WILL REMAIN MODERATE BUT STRONGER W OF 80W DUE TO THE PRESENCE OF DEAN. OUTLOOK PERIOD... FOR DAY 3 THE STRONG MID LEVEL RIDGE CENTER SHIFTS WWD TO NEAR 33N87W WITH AN AXIS EXTENDING E TO 32N45W. THE RIDGE EFFECTIVELY CUTS OFF THE WESTERLIES TO THE N AND DRIVES ALL SYSTEMS S OF 25N WWD IN A STRONG ELY FLOW. ON THE SURFACE DAY 3 HRCN DEAN FORECAST TO CONTINUE WWD INTO THE MEXICAN COAST NEAR 19N88W. THE ATLC RIDGE WILL REMAIN ALONG 30N WHILE THE TRPL WAVE MOVES INTO THE BAHAMAS. THE GFS DOESN'T DEVELOP THIS WAVE BUT OTHER MODELS DO THEREFORE IT WILL BE WATCHED CAREFULLY. FOR DAY 4 THE STRONG MID LEVEL RIDGE REMAINS STATIONARY NEAR 33N88W. THE WESTERLIES FIND A WAY TO PENETRATE S OF 30N BUT IT'S OVER THE ERN ATLC ALONG 32W. ON THE SURFACE DAY 4 HRCN DEAN MOVES INLAND OVER MEXICO BUT WINDS WILL REMAIN ABOVE NORMAL OVER THE SW GULF DAY 4. THE ATLC RIDGE WEAKENS BUT REMAINS ALONG 30N. CARIB AND ATLC TRADES MOSTLY 10 TO 15 KT AS A RESULT OF THE WEAK RIDGE. FOR DAY 5 SOME WEAKENING OF THE MID LEVEL RIDGE OVER THE SRN CONUS BUT IT REMAINS STATIONARY. MID LEVEL TROUGHING BETWEEN 40W AND 50W WEAKENS AS A STRONG SHORTWAVE LIFTS NE. ON THE SURFACE DAY 5 A MOSTLY BENIGN PATTERN WITH A WEAK ATLC RIDGE ALONG 30N AND WINDS OVER THE ENTIRE REGION MOSTLY 10 TO 15 KT. OF COURSE THIS IS ALL DEPENDENT ON NO TRPL SYSTEMS DEVELOPING. WARNINGS... SUBJECT TO CHANGE BASED ON LATEST NHC ADVISORY. ATLANTIC... NONE. CARIBBEAN... HURRICANE WARNING N OF 15N W OF 75W...AMZ082 GULF OF MEXICO... NONE. FORECASTER RRG