000 AXNT20 KNHC 171746 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SAT NOV 17 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 08N13W TO 05N17W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 05N17W TO 03N22W TO 06N33W THEN RESUMES NEAR 12N43W TO 11N50W TO 10N61W. A MIDDLE TO UPPER LEVEL LOW IS CENTERED NEAR 20N40W AND CONTINUES TO PRODUCE A BROAD AREA OF UPPER LEVEL DIFFLUENCE WHICH IS GENERATING WIDELY SCATTERED MODERATE CONVECTION FROM 07N-22N BETWEEN 243W-48W. THIS AREA IS FOCUSED ALONG A SURFACE TROUGH ANALYZED FROM 11N42W TO 19N33W. ELSEWHERE...SCATTERED MODERATE CONVECTION IS FROM 03N-07N BETWEEN 19W-25W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE CAROLINAS THIS AFTERNOON NEAR 34N82W AND EXTENDS A TROUGH AXIS SOUTHWARD ALONG 82W TO AS FAR SOUTH AS 10N OVER CENTRAL AMERICA. WHILE MOST OF THE ACTIVE WEATHER WITH THIS UPPER LEVEL FEATURE IS LOCATED IN THE SW NORTH ATLC...THE BACK SIDE OF THE TROUGHING IS PROVIDING MUCH OF THE GULF WITH NORTHWESTERLY UPPER LEVEL FLOW. WATER VAPOR IMAGERY INDICATES MOSTLY DRY AIR AND SUBSIDENCE IS FOUND N OF 23N BETWEEN 82W-93W. AT THE SURFACE...RIDGING PERSISTS OVER MUCH OF THE EASTERN CONUS WITH THE RIDGE AXIS EXTENDING FROM THE GREAT LAKES REGION S-SW ACROSS THE LOWER MISSISSIPPI RIVER VALLEY THE ALONG THE TEXAS AND EASTERN MEXICO GULF COASTS. NORTHEAST WINDS IN THE RANGE OF 10 TO 20 KT PREVAIL WITH LOW-LEVEL MOISTURE CONVERGENCE NOTED ON SATELLITE IMAGERY OVER THE SW GULF ALONG A SURFACE TROUGH ANALYZED FROM 18N94W TO 23N98W. ISOLATED SHOWERS ARE OCCURRING S OF 24N W OF 92W. OTHERWISE...ISOLATED SHOWERS AND TSTMS ARE OCCURRING OVER PORTIONS OF THE SE GULF AND PORTIONS OF THE FLORIDA STRAITS S OF 25N E OF 87W WHERE THE BASE OF THE AFOREMENTIONED UPPER LEVEL TROUGH IS LOCATED. CARIBBEAN SEA... AN UPPER LEVEL TROUGH IS LOCATED OVER THE FLORIDA PENINSULA WITH A TROUGH AXIS ALONG 82W DIPPING SOUTHWARD INTO THE WESTERN CARIBBEAN AND OVER PORTIONS OF CENTRAL AMERICA. WATER VAPOR IMAGERY INDICATES THAT WEST OF THE TROUGH AXIS MOSTLY FAIR WEATHER IS NOTED OVER THE NW CARIBBEAN...WESTERN CUBA...AND AREAS W OF 84W. NORTHERLY WINDS AT THE SURFACE PREVAIL AND THESE ARE EXPECTED TO PERSIST THROUGH TUESDAY. EAST OF THE UPPER LEVEL TROUGH AXIS...SOUTH-SOUTHWESTERLY MOISTURE-LADEN UPPER LEVEL FLOW DOMINATES AND CONTINUES TO PROVIDE OVERALL CLOUDY SKIES WITH SCATTERED SHOWERS AND ISOLATED TSTMS OVER MUCH OF THE AREA BETWEEN 70W-80W. AN AREA OF SCATTERED SHOWERS AND TSTMS ARE OCCURRING OVER THE SW CARIBBEAN WATERS FROM 10N-14N BETWEEN 79W-84W DUE LARGELY IN PART TO LOW-LEVEL MOISTURE CONVERGENCE OF EASTERLY TRADES AND THE AFOREMENTIONED NORTHERLY FLOW OVER THE NW CARIBBEAN. CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS EXTENDING ALONG 09N FROM THE EASTERN PACIFIC REGION IS ALSO A CONTRIBUTING FOCUS OF THE CONVECTION. ELSEWHERE OVER THE REMAINDER OF THE EASTERN CARIBBEAN...EMBEDDED ISOLATED SHOWERS WITHIN THE TRADE WIND FLOW CONTINUE TO MOVE EAST-NORTHEAST OVER THE LESSER ANTILLES AND PUERTO RICO THIS AFTERNOON. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE CAROLINAS NEAR 34N83W AND SUPPORTS A STATIONARY FRONT THAT EXTENDS ALONG 32N75W TO 26N79W. LOW-LEVEL MOISTURE CONVERGENCE IN THE VICINITY OF THE FRONT ALONG WITH MIDDLE TO UPPER LEVEL DIFFLUENCE EAST OF THE TROUGH AXIS IS GENERATING SCATTERED SHOWERS AND TSTMS WITHIN 75 NM EITHER SIDE OF THE FRONT S OF 29N AND FROM 29N-34N BETWEEN 71W-81W. FARTHER EAST OVER THE REMAINDER OF THE SW NORTH ATLC... MOIST SOUTHWESTERLY UPPER LEVEL FLOW DOMINATES BETWEEN THE PREVIOUSLY MENTIONED LOW AND TROUGHING AND AN UPPER LEVEL RIDGE AXIS THAT EXTENDS FROM THE EASTERN CARIBBEAN SEA NEAR 17N64W TO BEYOND 32N54W. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING OVER A LARGE AREA FROM 20N-32N BETWEEN 58W-75W AND REMAIN LARGELY FOCUSED ALONG A SURFACE TROUGH ANALYZED FROM 23N66W TO 30N63W TO 36N58W. ELSEWHERE OVER THE REMAINDER OF THE CENTRAL AND EASTERN ATLC...A SURFACE RIDGE PREVAILS AND IS ANCHORED BY A 1031 MB HIGH CENTERED SW OF THE AZORES NEAR 36N34W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN