000 AXNT20 KNHC 092339 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED OCT 09 2013 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... A 1010 MB LOW IS CENTERED NEAR 10N27W AND REMAINS EMBEDDED WITHIN THE MONSOON TROUGH. THE LOW IS THE FOCAL POINT OF A BROADER MONSOONAL GYRE WITH INFLUENCE FROM 08N-14N BETWEEN 23W- 37W. THE GYRE CONTINUES TO LIE BENEATH THE WESTERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONIC CIRCULATION PROVIDING AMPLE UPPER LEVEL DIFFLUENCE FOR WIDELY SCATTERED MODERATE CONVECTION FROM 11N-14N BETWEEN 28W-33W...AND ISOLATED MODERATE CONVECTION ELSEWHERE FROM 08N-14N BETWEEN 23W-35W. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 11N35W TO 19N36W MOVING W AT 10-15 KT. THE WAVE HAS MOVED ACROSS THE NORTHERN PERIPHERY OF THE MONSOONAL GYRE MENTIONED IN THE SPECIAL FEATURES SECTION IN THE PAST 24 HOURS AND RESIDUAL ENERGY IN THE VICINITY OF THE WAVE AXIS IS UNDER THE INFLUENCE OF DRIER AIR TO THE WEST AND INCREASED SOUTHWESTERLY SHEAR. GIVEN THE HOSTILE ENVIRONMENT FOR THE WAVE...NO SIGNIFICANT CONVECTION IS NOTED WITH THE WAVE AT THIS TIME. TROPICAL WAVE EXTENDS FROM 14N45W TO 21N46W MOVING W AT 5-10 KT. THE WAVE REMAINS WITHIN WEAK SURFACE TO 700 MB TROUGHING BETWEEN 42W-52W AND IT IS LIKELY A PORTION OF THE ENERGY ASSOCIATED WITH THE WAVE IS STRETCHING NORTHWARD INTO A MID-LEVEL MID-LATITUDE TROUGH TO THE NORTH WHILE AT THE SAME TIME INTERACTING WITH AN UPPER LEVEL LOW CENTERED NEAR 20N46W. ISOLATED MODERATE CONVECTION IS FROM 17N-23N BETWEEN 41W-47W. TROPICAL WAVE EXTENDS FROM 11N76W TO 18N74W MOVING W AT 10-15 KT. THE WAVE LIES WITHIN BROAD SURFACE TO 700 MB TROUGHING OVER THE CENTRAL AND WESTERN CARIBBEAN SEA AND FALLS BENEATH AN UPPER LEVEL TROUGH AXIS EXTENDING FROM 19N71W TO 12N77W. AS THE WAVE HAS CONTINUED TO MOVE WESTWARD OVER THE PAST 24 HOURS...MOST OF THE MOISTURE ADVECTION OCCURRING DUE TO THE UPPER LEVEL TROUGH REMAINS TO THE EAST WHILE ONLY ISOLATED MODERATE CONVECTION IS OCCURRING FROM 15N-19N BETWEEN 73W-77W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO 11N27W TO 09N34W TO 09N39W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 09N39W TO 09N50W. ASIDE FROM THE CONVECTION ASSOCIATED WITH THE SPECIAL FEATURES LOW...ISOLATED MODERATE CONVECTION IS FROM 02N-05N BETWEEN 11W-20W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL TROUGH AXIS EXTENDS FROM OVER THE SE CONUS NEAR 31N84W SOUTH-SOUTHWESTWARD TO A BASE NEAR 22N87W. THE TROUGHING SUPPORTS A STATIONARY FRONT ANALYZED FROM THE UPPER FLORIDA KEYS NEAR 25N80W TO WESTERN CUBA NEAR 22N84W ACROSS THE YUCATAN CHANNEL AND NORTHERN COAST OF THE YUCATAN PENINSULA TO 20N92W AND INTO A WEAK 1013 MB LOW CENTERED NEAR 18N94W. WATER VAPOR IMAGERY INDICATES MOST OF THE TROUGH ITSELF AND AREAS TO THE NORTH AND WEST REMAIN DRY AND STABLE WHILE THE AREA IN THE VICINITY OF THE FRONT AND S OF 21N ARE EXPERIENCING INCREASED CLOUDINESS AND ISOLATED SHOWERS AND TSTMS WITHIN 90 NM EITHER SIDE OF THE FRONT AND S OF 21N BETWEEN 90W-95W...INCLUDING INLAND PORTIONS OF THE YUCATAN PENINSULA. OTHERWISE...A SURFACE RIDGE AXIS EXTENDS FROM A 1022 MB HIGH CENTERED OVER EASTERN TENNESSEE NEAR 36N86W SW TO THE EAST-CENTRAL MEXICO COAST NEAR 22N98W. AS HIGH PRESSURE HAS BUILT IN ACROSS MUCH OF THE NORTHERN AND WESTERN GULF...MOSTLY CLEAR SKIES AND FAIR CONDITIONS ARE NOTED ON SATELLITE IMAGERY THIS EVENING. LIGHT NORTHEAST TO EASTERLY WINDS ARE EXPECTED IN THE RANGE OF 5 TO 15 KT THROUGH LATE THURSDAY AS THE FRONT SLOWLY DRIFTS EASTWARD INTO THE SW NORTH ATLC AND NW CARIBBEAN SEA REGIONS. CARIBBEAN SEA... A NARROW UPPER LEVEL RIDGE AXIS EXTENDS OVER THE NW CARIBBEAN BETWEEN TWO UPPER LEVEL TROUGHS ONE NOTED ON WATER VAPOR IMAGERY OVER THE EASTERN GULF OF MEXICO AND THE OTHER EXTENDING FROM OVER HISPANIOLA NEAR 19N71W TO 11N78W. UPPER LEVEL DIFFLUENT FLOW IS PRIMARILY OVER THE NW CARIBBEAN SOUTH OF A SURFACE STATIONARY FRONT ANALYZED FROM WESTERN CUBA TO THE NORTHERN YUCATAN PENINSULA COAST. LOW-LEVEL MOISTURE CONVERGENCE SOUTH OF THE BOUNDARY ALONG WITH THE UPPER LEVEL DYNAMICS IS GENERATING SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS N OF 15N W OF A LINE FROM 22N81W TO 16N84W. THE FRONT IS FORECAST TO GRADUALLY DRIFT SOUTHEASTWARD AND BECOME DIFFUSE OVER THE NEXT 24 TO 36 HOURS. FARTHER EAST...IN THE VICINITY OF THE EASTERN-MOST UPPER LEVEL TROUGH...A TROPICAL WAVE IS ALONG 75W. WHILE MOST OF THE UPPER LEVEL DIFFLUENCE IS LOCATED TO THE EAST OF THE TROPICAL WAVE AND UPPER LEVEL TROUGH AXIS...LOW-LEVEL CONVERGENCE ASSOCIATED WITH THE TROPICAL WAVE IS GENERATING ISOLATED SHOWERS AND TSTMS WITHIN 120 NM EITHER SIDE OF A LINE FROM 18N74W TO 13N82W. THE LOW-LEVEL CONVERGENCE CONTINUES ACROSS THE SW CARIBBEAN AS THE MONSOON TROUGH AXIS REMAINS ANALYZED FROM NORTHERN COLOMBIA ACROSS PANAMA TO SOUTHERN COSTA RICA WITH SCATTERED SHOWERS AND WIDELY SCATTERED STRONG TSTMS S OF 12N BETWEEN 69W-86W. CURRENTLY THE STRONGEST CONVECTION IS PARALLEL TO THE EAST PACIFIC COAST OF PANAMA AND COSTA RICA. FINALLY...A MARGINALLY DIFFLUENT UPPER LEVEL ENVIRONMENT IS NOTED ACROSS THE EASTERN CARIBBEAN WITH WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING E OF A LINE FROM SOUTHWESTERN HISPANIOLA NEAR 18N73W TO 12N65W. LOW-LEVEL MOISTURE CONTINUES TO ADVECT FROM THE TROPICAL ATLC INTO THE EASTERN CARIBBEAN AND RE-DIRECT NORTHWARD ON THE SOUTHERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONE CENTERED IN THE SW NORTH ATLC NEAR 22N62W. HISPANIOLA... CURRENTLY MIDDLE TO LOW-LEVEL MOISTURE...PEAK HEATING...AND INSTABILITY ARE GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS HISPANIOLA BETWEEN A TROPICAL WAVE TO THE SOUTHWEST ALONG 75W AND THE DIFFLUENT EASTERN PERIPHERY OF AN UPPER LEVEL TROUGH AXIS EXTENDING FROM OVER THE ISLAND NEAR 19N71W TO 11N78W. THIS MOISTURE STRETCHES EASTWARD TO 59W AND IS EXPECTED TO REMAIN IN PLACE OVER THE NEXT FEW DAYS WITH MAXIMUM AREAL COVERAGE OF CONVECTIVE ACTIVITY OCCURRING DURING THE AFTERNOON AND EVENING HOURS. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR IMAGERY CENTERED OVER THE MID-ATLC STATES NEAR 36N78W. THE TROUGH SUPPORTS A 1008 MB LOW CENTERED NEAR 34N76W WITH A COLD FRONT EXTENDING S-SW TO 31N77W WHICH CONTINUES SOUTHWESTWARD AS A STATIONARY FRONT TO THE UPPER FLORIDA KEYS NEAR 25N80W. ASIDE FROM THE LOW AND FRONTAL BOUNDARY...MUCH OF THE SW NORTH ATLC FALLS UNDER A VERY WEAK SURFACE PRESSURE GRADIENT WITH LOWER PRESSURE GENERALLY BETWEEN 60W-80W. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 300 NM EAST OF THE FRONT...BUT ARE ALSO OCCURRING FROM 18N-27N BETWEEN 58W-72W IN ASSOCIATION WITH AN UPPER LEVEL LOW CENTERED NEAR 26N67W. EVENTUALLY BY EARLY SATURDAY MOST OF THE SURFACE TROUGHING SHIFTS NORTH OF THE DISCUSSION AREA WITH HIGH PRESSURE RIDGING BUILDING IN FROM BOTH THE EAST ACROSS THE CENTRAL ATLC AND THE WEST FROM THE NE GULF OF MEXICO. UNTIL THEN...CONDITIONS ARE EXPECTED TO REMAIN RATHER DISORGANIZED AND UNSETTLED WITH SHOWERS AND TSTM ACTIVITY. FARTHER EAST...A SURFACE RIDGE INFLUENCES THE CENTRAL ATLC N OF 23N BETWEEN 40W-60W ANCHORED BY A 1023 MB HIGH CENTERED NEAR 35N54W. THE SURFACE RIDGING STRETCHES ACROSS THE EASTERN ATLC...HOWEVER IS SLIGHTLY WEAKER DUE TO A DISSIPATING COLD FRONT EXTENDING FROM 32N29W SW TO 28N41W AND SUPPORTED ALOFT BY A DEEP LAYERED LOW CENTERED NW OF THE AZORES NEAR 44N37W. NO SIGNIFICANT PRECIPITATION IS OCCURRING ALONG THE FRONT AT THIS TIME. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN