000 AXNT20 KNHC 202356 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SUN NOV 20 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... A LARGE-SCALE TROUGH IS LOCATED OVER THE CENTRAL ATLC WITH AXIS ALONG 59W AND A BASE NEAR 21N. EMBEDDED WITHIN THIS TROUGHING... WATER VAPOR IMAGERY INDICATES A SHORTWAVE WITH AXIS FROM 28N56W TO 21N47W. THIS UPPER LEVEL FEATURE SUPPORTS A 1009 MB LOW CENTERED NEAR 23N53W AND A SURFACE TROUGH ANALYZED FROM 19N53W THROUGH THE LOW TO 29N52W. THIS LOW REMAINS THE FOCUS FOR POTENTIAL TROPICAL OR SUB-TROPICAL CYCLONE GENESIS WITHIN THE NEXT 48 HOURS. WHILE UPPER LEVEL DIFFLUENCE CONTINUES TO BE MAXIMIZED NORTH AND EAST OF THE TROUGHING...SCATTERED MODERATE CONVECTION IS OCCURRING FROM 23N-32N BETWEEN 42W-54W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N15W TO 09N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 09N18W TO 08N40W TO 06N55W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 05N-10N BETWEEN 16W-24W. SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 05N-12N BETWEEN 08W-32W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL RIDGE AXIS EXTENDS FROM SOUTHERN MEXICO OVER THE WESTERN GULF AND INTO THE SE CONUS. DRY AIR AND SUBSIDENT CONDITIONS PREVAIL ALOFT ACROSS THE GULF WHICH IS SUPPORTIVE OF A SURFACE RIDGE WITH AXIS EXTENDING SW FROM A 1027 MB HIGH CENTERED OVER EASTERN SOUTH CAROLINA NEAR 33N80W. FAIR WEATHER AND OVERALL STABLE CONDITIONS ARE NOTED ON SATELLITE IMAGERY ACROSS THE BASIN WITH ONLY A SMALL AREA OF ISOLATED SHOWERS OCCURRING WITHIN 60 NM EITHER SIDE OF A LINE FROM THE FLORIDA PANHANDLE NEAR 31N86W TO 27N89W...AND ACROSS THE SOUTHERN FLORIDA PENINSULA INTO THE SE GULF S OF 27N E OF 85W. ELSEWHERE...E TO SE WINDS ARE IN THE RANGE OF 10-20 KT THIS EVENING. THE RIDGE IS FORECAST TO REMAIN NEARLY STATIONARY ACROSS THE GULF WITH LITTLE CHANGE IN CONDITIONS THROUGH TUESDAY WITH THE NEXT COLD FRONT EXPECTED TO EMERGE OFF THE TEXAS GULF COAST LATE TUESDAY INTO EARLY WEDNESDAY. CARIBBEAN SEA... WEAK UPPER LEVEL TROUGHING IS EVIDENT ACROSS THE SW CARIBBEAN AND ALONG WITH CONVERGENT LOW-LEVEL NORTHEASTERLY WINDS...THE RESULT IS ISOLATED SHOWERS AND TSTMS OCCURRING ACROSS INLAND PORTIONS OF THE YUCATAN PENINSULA...HONDURAS...NICARAGUA...AND PANAMA THIS EVENING. A FEW OF THESE SHOWERS EXTEND EASTWARD OVER ADJACENT CARIBBEAN WATERS FROM 10N-14N W OF 75W. THE REMAINDER OF THE CARIBBEAN BASIN IS UNDER THE INFLUENCE OF SUBSIDENT DRY AIR ALOFT AND THE NE WINDS ORIGINATING FROM THE WESTERN PERIPHERY OF THE SPECIAL FEATURES LOW MENTIONED ABOVE. A FEW LOW-TOPPED ISOLATED SHOWERS ARE OCCURRING OVER THE NE CARIBBEAN N OF 16N BETWEEN 62W-70W...AND S OF 14N BETWEEN 60W-72W... INCLUDING THE WINDWARD AND ABC ISLANDS THIS EVENING. AS THE NE WINDS CONTINUE OVER THE SW NORTH ATLC ACROSS THE GREATER ANTILLES AND INTO NORTHERN PORTIONS OF THE BASIN...STRONGER WINDS ARE ANTICIPATED THROUGH LATE MONDAY IN THE VICINITY OF THE MONA AND WINDWARD PASSAGES. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE AXIS EXTENDS FROM THE WESTERN GULF OF MEXICO NORTHEASTWARD ACROSS THE SE CONUS TO THE MID-ATLC SEABOARD AND SUPPORTS A 1027 MB HIGH CENTERED OVER EASTERN SOUTH CAROLINA NEAR 33N80W. MOSTLY NE WINDS DOMINATE ACROSS THE W ATLC WEST OF 60W WITH ISOLATED SHOWERS POSSIBLE S OF 28N BETWEEN 60W-70W AND FROM 23N-29N W OF 72W...INCLUDING THE INTERIOR SOUTHERN FLORIDA PENINSULA S OF 28N. FARTHER EAST...AN UPPER LEVEL TROUGH IS OVER THE CENTRAL ATLC ALONG 59W THAT SUPPORTS THE 1009 MB SPECIAL FEATURES LOW AND AREA OF CONVECTION LOCATED MAINLY EAST OF THE UPPER LEVEL TROUGHING FROM 23N-32N BETWEEN 42W-54W. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE PROVIDING NE TO E WINDS IN THE 15 TO 20 KT RANGE S OF 32N E OF 35W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN