000 AXNT20 KNHC 131055 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE MAY 13 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 55W S OF 10N MOVING W 10-15 KT. THE WAVE COUPLED WITH THE ITCZ IS ENHANCING CONVECTION OVER THE GUIANAS REGION. SCATTERED MODERATE CONVECTION IS FROM EQUATOR TO 4N BETWEEN 53W-58W. SIMILAR CONVECTION IS FROM 6N-8N BETWEEN 52W-55W. THE GFS MODEL HAS LOW-LEVEL MOISTURE FROM THIS TROPICAL WAVE SPREADING OVER GUYANA...E VENEZUELA AND THE S WINDWARD ISLANDS ON WED. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 8N12W 3N25W 2N31W 1N37W 4N52W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM EQ-3N BETWEEN THE PRIME MERIDIAN AND 3W. SIMILAR CONVECTION IS FROM 2N-5N BETWEEN 24W-29W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF A LINE FROM 3N33W TO 8N41W. SCATTERED MODERATE CONVECTION IS FROM 3N-6N BETWEEN 45W-48W. ...DISCUSSION... GULF OF MEXICO... A STRONG UPPER LEVEL ANTICYCLONIC CIRCULATION IS OFFSHORE OF THE MID-ATLANTIC STATES MOVING SLOWLY SE ACROSS THE OCEAN. AS OF 0900 UTC...THE ASSOCIATED COLD FRONT ENTERS THE FORECAST AREA NEAR 32N62W THEN CONTINUES ACROSS THE CENTRAL BAHAMAS AND STRAITS OF FLORIDA. A VERY FINE LOW LEVEL CLOUD LINE DEFINES THE BOUNDARY ACROSS THE SE GULF WITH NO PRECIPITATION ASSOCIATED WITH FRONT. A 1016 MB SURFACE HIGH PRESSURE IS CENTERED NEAR COASTAL ALABAMA AND SETTLING INTO THE E GULF PROVIDING A MUCH COOLER AND DRIER AIR MASS. THIS HIGH PRESSURE WILL BE SUPPORTED BY A STRENGTHENING UPPER LEVEL RIDGE ANCHORED OVER THE GULF OF HONDURAS WITH RIDGE AXIS ALONG 90W KEEPING MAINLY NW FLOW ALOFT ACROSS MUCH OF THE GULF OF MEXICO DURING THE NEXT 24 HOURS. RETURN SOUTHEASTERLY 15-20 KT SURFACE FLOW IS EXPECTED W OF 90W AHEAD OF NEXT DEVELOPING LOW PRESSURE SYSTEM OVER W TEXAS WED. CARIBBEAN SEA... A MID TO UPPER LEVEL HIGH CENTERED OVER THE GULF OF HONDURAS EXTENDS A RIDGE OVER THE W AND CENTRAL CARIBBEAN WHILE UPPER TROUGHING RUNS FROM THE N LEEWARD ISLANDS TO THE N COAST OF VENEZUELA. MODERATE TO STRONG SUBSIDENCE/DRY AIR IS EVIDENT ACROSS MUCH OF THE CARIBBEAN SEA SUPPRESSING THE DEVELOPMENT OF ANY SIGNIFICANT CONVECTION. AT THE SURFACE...HIGH PRESSURE OVER THE E ATLC NEAR 29N36W EXTENDS A RIDGE TO THE E CARIBBEAN SEA INCLUDING PUERTO RICO AND THE VIRGIN ISLANDS. THIS RIDGE IS PROVIDING MOSTLY FAIR WEATHER AND A PREVAILING E-SE SURFACE WIND REGIME ACROSS THE N LEEWARD ISLANDS AND PUERTO RICO. ELSEWHERE LIGHT TO MODERATE TRADE WINDS OF 10 TO 20 KT ARE ACROSS THE CARIBBEAN SEA AS FAIR WEATHER AND CLEAR SKIES DOMINATE THE REGION. WITH CURRENT MOVEMENT OF TROPICAL WAVE ACROSS GUYANA AND E VENEZUELA TROPICAL MOISTURE WILL INCREASE ACROSS TRINIDAD AND TOBAGO AND THE S WINDWARD ISLANDS ON WED. ATLANTIC OCEAN... A STRONG DEEP-LAYERED CYCLONIC CIRCULATION CENTER IS OFFSHORE OF THE MID-ATLANTIC STATES NEAR 36N69W. ASSOCIATED COLD FRONT ENTERS THE FORECAST AREA NEAR 32N62W THEN CONTINUES ACROSS ELEUTHERA BAHAMAS TO THE STRAITS OF FLORIDA. SCATTERED SHOWERS AND THUNDERSTORMS ARE WITHIN 90 NM E OF THE FRONT N OF 25N. BEHIND FRONT...SURFACE HIGH PRESSURE RIDGE ACROSS THE SE U.S. WILL CONTINUE TO BUILD INTO THE W ATLC WATERS ON WED. THE REMAINDER OF THE DISCUSSION AREA IS UNDER THE INFLUENCE OF A 1024 MB SURFACE HIGH PRESSURE CENTERED NEAR 29N36W. THIS IS PROVIDING FAIR WEATHER WITH ONLY PATCHES OF SCATTERED LOW-LEVEL CLOUDINESS ACROSS MUCH OF THE CENTRAL AND E ATLC N OF 15N. A BROAD MID TO UPPER RIDGE COVERS THE DEEP TROPICS WITH AXIS EXTENDING ALONG 10N. THIS UPPER FEATURE IS AIDING TO ENHANCE CONVECTION ALONG THE ITCZ WEST OF 32W. $$ HUFFMAN