000 AXNT20 KNHC 101755 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT SEP 10 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 NATE IS CENTERED NEAR 20.1N 94.2W AT 10/1800 UTC OR 125 NM TO THE E-NE OF VERACRUZ MEXICO AND 185 NM E-SE OF TUXPAN MEXICO MOVING W AT 2 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. WIDELY SCATTERED MODERATE CONVECTION IS FROM 17N TO 22N BETWEEN 92W AND 97W WITH AN OUTER BAND OF SCATTERED MODERATE CONVECTION EXTENDING WITHIN 60 NM EITHER SIDE OF A LINE FROM 25N91W TO 22N96W. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT5/WTNT35 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. TROPICAL STORM MARIA IS CENTERED NEAR 17.3N 61.5W AT 10/1500 UTC OR 20 NM NE OF ANTIGUA AND 270 NM E-SE OF SAN JUAN PUERTO RICO MOVING NW AT 13 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. NUMEROUS MODERATE AND SCATTERED STRONG CONVECTION IS FROM 09N TO 22N BETWEEN 57W AND 62W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. POST-TROPICAL CYCLONE KATIA IS CENTERED NEAR 44.7N 47.7W AT 10/1500 UTC OR 255 NM E-SE OF CAPE RACE NEWFOUNDLAND AND 1700 NM W-SW OF GLASGOW SCOTLAND MOVING E-NE AT 46 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 954 MB. MAXIMUM SUSTAINED WIND SPEED IS 70 KT WITH GUSTS TO 85 KT. WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 240 NM NORTH QUADRANT OF THE CENTER OF KATIA. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS ANALYZED FROM 17N38W TO 08N45W MOVING W AT 15-20 KT. A FAIRLY AMPLIFIED AND ELONGATED LOW-LEVEL CYCLONIC FLOW IS EVIDENT ON VISIBLE SATELLITE IMAGERY IN THE VICINITY OF THE WAVE AXIS ACROSS THE CENTRAL TROPICAL ATLC. TOTAL PRECIPITABLE WATER IMAGERY ALSO INDICATES THE PRESENCE OF INCREASED LOW-LEVEL MOISTURE FROM 10N TO 19N BETWEEN 35W AND 44W. SCATTERED MODERATE CONVECTION REMAINS MOSTLY EAST OF THE WAVE AXIS OCCURRING FROM 10N TO 14N BETWEEN 36W AND 43W. ISOLATED MODERATE CONVECTION IS ALSO OCCURRING WITHIN 30 NM EITHER SIDE OF A LINE FROM 13N44W TO 10N48W. TROPICAL WAVE IS ANALYZED FROM 18N79W TO 10N80W MOVING W AT 10-15 KT. THE WAVE IS BECOMING EMBEDDED WITHIN A BROAD LOW-LEVEL CYCLONIC MONSOONAL GYRE ACROSS THE SW CARIBBEAN UNDER FAIRLY DIVERGENT UPPER LEVEL FLOW DUE TO UPPER LEVEL RIDGING ACROSS THE CENTRAL CARIBBEAN SEA. WIDELY SCATTERED MODERATE CONVECTION IS PRIMARILY OCCURRING EAST OF THE WAVE AXIS FROM 13N TO 17N BETWEEN 74W AND 79W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N15W TO 07N20W TO 07N27W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N27W TO 13N40W THEN RESUMES NEAR 08N46W TO 09N56W. SCATTERED MODERATE CONVECTION IS FROM 07N TO 11N BETWEEN 14W AND 18W...AND FROM 05N TO 10N BETWEEN 27W AND 32W. ...DISCUSSION... GULF OF MEXICO... WHILE TROPICAL STORM NATE CONTINUES TO TRACK ACROSS THE SOUTHWESTERN GULF THIS AFTERNOON...A DISSIPATING STATIONARY FRONTAL BOUNDARY EXTENDS FROM THE SW NORTH ATLC WATERS ACROSS THE CENTRAL FLORIDA PENINSULA INTO THE EASTERN GULF WATERS ALONG 28N83W TO 26N88W. ISOLATED SHOWERS AND TSTMS ARE EVIDENT ON TAMPA BAY DOPPLER RADAR IMAGERY OCCURRING WITHIN 15 NM OF A LINE FROM 28N82W TO 27N83W. OTHERWISE...CONVECTION IS LIMITED TO THE WESTERN GULF W OF 90W IN ASSOCIATION WITH NATE. ACROSS EXTREME PORTIONS OF THE NW GULF...INFLUENCES FROM A 1017 MB HIGH CENTERED OVER SE LOUISIANA ARE PROVIDING FOR MOSTLY CLEAR SKIES AND FAIR CONDITIONS N OF 27N. UPPER LEVEL RIDGING EXTENDS ACROSS THE SOUTHERN GULF WITH RIDGE AXIS FROM 28N75W IN THE SW NORTH ATLC TO 21N94W WHICH IS PROVIDING NATE WITH AMPLE UPPER LEVEL DIFFLUENCE TO SUSTAIN CONVECTION OVER THE SW GULF. CARIBBEAN SEA... AN UPPER LEVEL RIDGE IS MOSTLY IN CONTROL OVER MUCH OF THE CENTRAL AND WESTERN CARIBBEAN PROVIDING OVERALL EASTERLY DIFFLUENT UPPER LEVEL FLOW. WITH LOW-LEVEL MOISTURE IN PLACE BETWEEN A LOW-LEVEL MONSOONAL GYRE CENTERED OVER THE SW CARIBBEAN AND A TROPICAL WAVE MOVING W NEAR 80W...WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING OVER MUCH OF THE CARIBBEAN BASIN THIS AFTERNOON S OF 20N W OF 72W. THE ONLY SIGNIFICANT CONCENTRATION OF CONVECTIVE ACTIVITY IS THE CLUSTER OF SHOWERS AND TSTMS LOCATED EAST OF THE TROPICAL WAVE FROM 13N-17N BETWEEN 74W-79W. OVER THE EASTERN CARIBBEAN...TROPICAL STORM MARIA CONTINUES TO IMPACT THE LEEWARD ISLANDS AND NE CARIBBEAN WITH CONVECTION STRETCHING FROM NEAR TRINIDAD AND TOBAGO NORTHWARD TO 22N BETWEEN 57W-62W. AS THE STORM TRACKS NW OVER THE NEXT 24 HOURS...HEAVY PRECIPITATION IS EXPECTED TO CONTINUE OVER THE LESSER ANTILLES...US/UK VIRGIN ISLANDS...AND PUERTO RICO. ATLANTIC OCEAN... TROPICAL STORM MARIA CONTINUES TO SKIRT THE LEEWARD ISLANDS WHILE THE CENTER REMAINS IN THE TROPICAL NORTH ATLC WATERS. SCATTERED SHOWERS AND TSTMS ARE OCCURRING ACROSS A LARGE PORTION OF THE WATERS EAST OF THE LESSER ANTILLES FROM 09N-22N BETWEEN 57W-62W. SOME OF THIS PRECIPITATION AND DEBRIS MOISTURE IS BEING ADVECTED TO THE NORTH DUE TO AN UPPER LEVEL LOW CENTERED NEAR 25N63W. OTHERWISE OVER THE SW NORTH ATLC...AN UPPER LEVEL RIDGE IS CENTERED NEAR 29N74W AND IS PROVIDING A DIFFLUENT ENVIRONMENT BETWEEN THE RIDGE AND UPPER LEVEL TROUGHING OVER THE EASTERN CONUS. AT THE SURFACE...A DISSIPATING STATIONARY FRONT IS ANALYZED FROM 30N78W TO THE CAPE CANAVERAL AREA WITH ISOLATED SHOWERS AND TSTMS FROM 29N-31N BETWEEN 69W-79W. ALSO A SURFACE TROUGH IS ANALYZED FROM 26N72W TO 22N75W AND IS PROVIDING ISOLATED SHOWERS TO THE SE BAHAMAS AND ADJACENT ATLC WATERS FROM 22N-27N BETWEEN 70W-75W. THE REMAINDER OF THE CENTRAL AND EASTERN ATLC WATERS ARE UNDER THE INFLUENCE OF SURFACE RIDGING ANCHORED BY A 1022 MB HIGH CENTERED NEAR 29N31W AND A 1020 MB HIGH CENTERED NEAR 29N55W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN