000 AXNT20 KNHC 201148 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SUN MAY 20 2012 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...SPECIAL FEATURES... TROPICAL STORM ALBERTO IS CENTERED NEAR 31.7N 79.3W AT 20/1200 UTC OR ABOUT 80 NM SSE OF CHARLESTON SOUTH CAROLINA AND ABOUT 100 NM ESE OF SAVANNAH GEORGIA MOVING WSW OR 245 DEGREES AT 5 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 998 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH HIGHER GUSTS. SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. HEAVY SHOWERS WITH SCATTERED THUNDERSTORMS ARE 90 NM OF THE CENTER IN THE NW QUADRANT INCLUDING THE COAST OF SOUTH CAROLINA S OF MYRTLE BEACH. SCATTERED SHOWERS COVER THE REMAINDER OF THE AREA FROM 30N-34N BETWEEN 77W-81W. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 11N31W TO 5N34W MOVING W NEAR 15 KT. WAVE REMAINS EMBEDDED WITHIN A SURGE OF DEEP LAYERED MOISTURE AS EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...AREA IS VOID OF DEEP CONVECTION. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS INTO THE E TROPICAL OFF W AFRICA NEAR 11N15W ALONG 8N15W TO 1N18W WHERE THE ITCZ AXIS CONTINUES ALONG 00N19W TO 5N32W THEN RESTARTS W OF THE TROPICAL WAVE NEAR 5N36W CONTINUING ALONG 3N43W TO INLAND OVER SOUTH AMERICA NEAR 2N51W. SCATTERED/NUMEROUS STRONG CONVECTION HAS MOVED OFF W AFRICA AND IS FROM 2N-4N BETWEEN 8W-12W AND WITHIN 150 NM ALONG THE COAST OF LIBERIA AND SIERRA LEONE WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 150 NM ALONG THE COAST OF GUINEA S OF 10N. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 45 NM OF 4N E OF 3W TO THE PRIME MERIDIAN AND FROM 1N-4N BETWEEN 12W-18W. ...DISCUSSION... GULF OF MEXICO... AN UPPER RIDGE AXIS EXTENDS ALONG THE COAST OF MEXICO AND TEXAS FROM AN UPPER HIGH IN THE E PACIFIC REGION COVERING THE W GULF WHILE AN UPPER TROUGH COVERS THE E GULF INTO THE W ATLC. A WEAK SURFACE RIDGE EXTENDS FROM A 1020 MB HIGH OVER E TENNESSEE OVER THE W GULF TO THE W BAY OF CAMPECHE WITH STRONG SUBSIDENCE AND DRY STABLE AIR COVERING THE ENTIRE GULF. A SURFACE TROUGH EXTENDS AT 20/0900 UTC FROM 24N87W OVER THE NE YUCATAN PENINSULA NEAR 21N87W INTO THE W CARIBBEAN WITH ISOLATED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS S OF 25N E OF 86W TO OVER CUBA...THE FLORIDA KEYS AND THROUGH THE STRAITS OF FLORIDA. THE REMAINDER OF THE GULF IS UNDER MOSTLY CLEAR SKIES. THE SURFACE TROUGH WILL REMAIN NEARLY STATIONARY THROUGH THU. CARIBBEAN SEA... BROAD UPPER RIDGE OVER THE W GULF OF MEXICO COVERS THE ENTIRE CARIBBEAN BASIN WITH A RIDGE AXIS EXTENDING FROM OVER CENTRAL AMERICA NEAR 14N89W TO ACROSS HISPANIOLA THROUGH THE WINDWARD PASSAGE INTO THE W ATLC. A SURFACE TROUGH EXTENDS FROM THE GULF OF HONDURAS NEAR 16N87W OVER NE YUCATAN PENINSULA INTO THE GULF OF MEXICO NEAR 21N87W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE OVER THE W CARIBBEAN W OF A LINE FROM THE WINDWARD PASSAGE TO THE TIP OF NICARAGUA/HONDURAS. MODERATE TO FRESH EASTERLY TRADE WINDS ARE ACROSS THE BASIN USHERING IN SOME ISOLATED LOW LEVEL SHOWERS ACROSS THE E CARIBBEAN E OF 67W TO OVER THE LESSER ANTILLES. THE TRADE WINDS WILL PERSIST THROUGH THU. THE SURFACE TROUGH WILL REMAIN NEARLY STATIONARY THROUGH THU. ATLANTIC OCEAN... TROPICAL STORM ALBERTO IS THE PRIMARY FOCUS THIS MORNING...SEE SPECIAL FEATURES ABOVE. THE UPPER TROUGH OVER THE E GULF OF MEXICO EXTENDS INTO THE W ATLC N OF 22N W OF 70W SUPPORTING A SURFACE TROUGH THAT EXTENDS AT 20/0900 UTC FROM 32N75W ALONG 28N76W TO THE FLORIDA COAST BETWEEN FORT LAUDERDALE AND MIAMI WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 150 NM S AND W OF THE TROUGH. A SECOND SURFACE TROUGH EXTENDS FROM 28N73W ACROSS THE S BAHAMA ISLANDS TO NEAR 21N74W. SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS ARE WITHIN 300 NM E OF THE TROUGH AXIS. AN UPPER RIDGE AXIS IS E OF THE ABOVE UPPER TROUGH EXTENDING FROM THE BROAD UPPER RIDGE OVER THE CARIBBEAN OVER THE WINDWARD PASSAGE TO BEYOND 32N62W ENHANCING THE ACTIVITY ABOVE. A VERY BROAD SURFACE RIDGE DOMINATES THE REMAINDER OF THE ATLC N OF 15N BETWEEN AFRICA AND 70W ANCHORED BY A 1035 MB HIGH ABOUT 550 NM WSW OF THE AZORES. THE SURFACE TROUGH S OF ALBERTO WILL REMAIN IN THE W ATLC THROUGH TUE WHILE THE SECOND SURFACE TROUGH WILL REMAIN THROUGH MON THEN DISSIPATE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW