000 AXNT20 KNHC 121753 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON SEP 12 2011 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... TROPICAL STORM MARIA IS CENTERED NEAR 20.7N 67.3W AT 12/1500 UTC OR ABOUT 150 NM N-NW OF SAN JUAN PUERTO RICO AND ABOUT 710 NM S OF BERMUDA MOVING W AT 2 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 19N-22N BETWEEN 62W-66W. ISOLATED MODERATE CONVECTIVE IS FARTHER SE FROM THE CENTER OF MARIA OCCURRING OVER THE NE CARIBBEAN SEA FROM 10N-18N BETWEEN 62W-68W...IMPACTING THE US/UK VIRGIN ISLANDS AND PORTIONS OF THE NORTHERN LEEWARD ISLANDS. MARIA IS EXPECTED TO PRODUCE TOTAL RAIN ACCUMULATIONS OF 2-4 INCHES WITH ISOLATED MAXIMUM AMOUNTS OF 6 INCHES OVER THE VIRGIN ISLANDS... PUERTO RICO...AND PORTIONS OF THE NORTHERN LEEWARD ISLANDS THROUGH TUE. SEE THE LATEST FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS ANALYZED FROM 12N53W TO 22N51W MOVING W AT 15-20 KT. THE WAVE IS EMBEDDED WITHIN AN AREA OF MAXIMUM DEEP LAYER MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. METEOSAT-9 VISIBLE SATELLITE IMAGERY ALSO SHOWS CYCLONIC TURNING OF THE LOW-LEVEL CLOUD FIELD IN THE VICINITY OF THE WAVE AXIS. FURTHERMORE...AN EARLIER MORNING ASCAT PASS 12/1326 UTC DEPICTED THOSE SURFACE CYCLONIC WINDS WITH SOME 20 KT NE WINDS NEAR 20N52W. NO SIGNIFICANT DEEP CONVECTION IS ASSOCIATED WITH THE WAVE. TROPICAL WAVE IS ANALYZED FROM 13N84W TO 17N86W TO 22N87W MOVING W-NW AT 5-10 KT. LOW TO MID-LEVEL CYCLONIC TURNING OF THE CLOUD FIELD IS NOTED ALONG THE WAVE AXIS AS IT MOVES BENEATH THE SOUTHERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 19N87W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS OCCURRING FROM 15N-19N BETWEEN 83W-89W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W ALONG 07N28W TO 08N37W. ISOLATED MODERATE CONVECTION IS FROM 04N-13N BETWEEN 12W-37W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER LEVEL TROUGH IS SWINGING ACROSS THE SOUTHEASTERN CONUS AND DIPS SOUTHWARD INTO THE GULF WATERS REMAINING N OF 23N. THIS TROUGH IS SUPPORTING A STATIONARY FRONT EXTENDING FROM NE FLORIDA NEAR JACKSONVILLE SW TO NEAR 28N84W. WHILE THE FRONT REMAINS PRECIPITATION FREE...PRE-FRONTAL LOW-LEVEL MOISTURE AND CONVERGENCE FOCUSED ALONG A SURFACE TROUGH EXTENDING FROM LAKE OKEECHOBEE SW TO 25N83W IS GENERATING ISOLATED SHOWERS AND TSTMS WITHIN 60 NM EITHER SIDE OF THE SURFACE TROUGH. WATER VAPOR IMAGERY INDICATES THAT VERY DRY AIR IS ASSOCIATED WITH THE UPPER LEVEL TROUGH AND THAT VERY STRONG SUBSIDENCE CONTINUES TO PROGRESS ACROSS THE NORTHERN GULF WATERS THIS AFTERNOON. THIS OVERALL DRYING IS SUPPORTIVE OF A SURFACE RIDGE EXTENDING FROM A 1021 MB HIGH CENTERED OVER SW ALABAMA SOUTHWESTWARD TO EAST- CENTRAL MEXICO NEAR 21N97W. MOSTLY NE WINDS TO 15 KT ARE EXPECTED TO PERSIST THROUGH LATE WEDNESDAY ACROSS MUCH OF THE GULF AS THE RIDGE REMAINS FAIRLY STATIONARY. CARIBBEAN SEA... TROPICAL STORM MARIA CONTINUES TO IMPACT THE EASTERN CARIBBEAN WITH SCATTERED SHOWERS AND ISOLATED TSTMS W OF 68W TO THE LESSER ANTILLES NEAR 60W. THIS AREA OF PRECIPITATION ASSOCIATED WITH MARIA IS ENHANCED DUE TO AN UPPER LEVEL RIDGE AXIS EXTENDING FROM CUBA ACROSS HISPANIOLA TO NEAR 17N63W...AND IS FORECAST TO TRACK NW AS MARIA MOVES MORE NORTH OF THE BASIN. THE CENTRAL CARIBBEAN REMAINS FAIRLY QUIET THIS AFTERNOON CONVECTIVELY AS WELL AS AT THE SURFACE AS WINDS ARE EXPECTED TO REMAIN EASTERLY IN THE RANGE OF 10 TO 15 KT. FARTHER WEST...A TROPICAL WAVE OVER THE NW CARIBBEAN IS BEGINNING TO MOVE INLAND OVER PORTIONS OF CENTRAL AMERICA. CURRENTLY NUMEROUS SHOWERS AND SCATTERED STRONG TSTMS ARE OCCURRING FROM 15N-19N BETWEEN 83W-89W...INCLUDING THE GULF OF HONDURAS. AS THIS TROPICAL WAVE SLOWLY MOVES W-NW... HEAVY RAINFALL IS EXPECTED TO CONTINUE ACROSS INTERIOR PORTIONS OF BELIZE...HONDURAS...THE YUCATAN PENINSULA...AND GUATEMALA WITH THE POSSIBILITY OF FLASH FLOODING AND MUDSLIDES. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH IS SWEEPING ACROSS THE SE CONUS AND SUPPORTS A STATIONARY FRONT EXTENDING FROM 32N81W TO 30N81W THEN SW INTO THE NE GULF OF MEXICO. A PRE-FRONTAL SURFACE TROUGH IS ANALYZED SE OF THE FRONT FROM 29N80W TO LAKE OKEECHOBEE. LOW- LEVEL MOISTURE CONVERGENCE ALONG WITH LIFT PROVIDED BY THE UPPER LEVEL TROUGHING IS GENERATING SCATTERED SHOWERS AND TSTMS WITHIN 120 NM EITHER SIDE OF A LINE FROM 32N76W TO 24N80W OVER THE SW NORTH ATLC WATERS. FARTHER TO THE SE...TROPICAL STORM MARIA IS FORECAST TO CONTINUE TRACKING W-NW AND BEGIN A MORE NORTHWARD TRACK OVER THE NEXT FEW DAYS. AN UPPER LEVEL LOW CENTERED NEAR 26N65W IS ADVECTING MIDDLE TO UPPER LEVEL MOISTURE OVER A LARGE PORTION OF THE W ATLC WITH WIDELY SCATTERED SHOWERS OCCURRING FROM 22N-29N BETWEEN 57W-65W. OTHERWISE THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1026 MB HIGH CENTERED NEAR 29N39W AND A 1025 MB HIGH CENTERED NEAR 31N54W. INFRINGING ON THE EASTERN-MOST HIGH IS A COLD FRONT ANALYZED FROM 32N37W TO 32N43W. ISOLATED SHOWERS ARE OCCURRING WITHIN 75 NM EITHER SIDE OF THE FRONT BETWEEN 36W-44W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN