000 AXNT20 KNHC 121142 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST THU NOV 12 2009 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 9N13W 9N30W 8N33W 5N54W. A SURFACE TROUGH IS EMBEDDED WITHIN THE AXIS ALONG 31W FROM 6N-12N. SCATTERED MODERATE/ISOLATED STRONG CONVECTION SURROUNDS THE SURFACE TROUGH FROM 7N-17N BETWEEN 16W-31W AND FROM 5N-9N BETWEEN 31W-42W. THIS ACTIVITY IS LARGELY ENHANCED BY AN UPPER DIFFLUENT PATTERN EAST OF AN UPPER LEVEL TROUGH AXIS ALONG 30W. ...DISCUSSION... GULF OF MEXICO... UPPER LEVEL WESTERLY FLOW DOMINATES ACROSS THE GULF OF MEXICO WEST OF AN UPPER LEVEL SHORTWAVE TROUGH CURRENTLY LOCATED OVER THE MID-ATLANTIC STATES MOVING OFF TO THE NE. WITH THE RECENT COLD FRONTAL PASSAGE WITHIN THE LAST 24 HOURS...STRONG NORTHERLY WINDS UP TO 25 KT ARE OBSERVED ACROSS THE GULF. STRONG SUBSIDENCE IS ALSO NOTED ON WATER VAPOR IMAGERY OVER THE GULF PROVIDING A COOLER AND STABLE AIRMASS OVER THE REGION. THE NORTHERLY WINDS ARE FORECAST TO GRADUALLY DIMINISH THROUGH FRIDAY...WITH S-SE RETURN FLOW BEGINNING OVER WESTERN PORTIONS OF THE GULF BY EARLY SATURDAY AHEAD OF A DEVELOPING AREA OF LOW PRESSURE OVER THE SOUTHERN U.S. PLAINS AND THE ASSOCIATED COLD FRONT WHICH IS EXPECTED TO ENTER THE NW GULF WATERS BY MONDAY. CARIBBEAN SEA... A COLD FRONT EXTENDS FROM THE W ATLC ACROSS CENTRAL CUBA AND INTO THE NW CARIBBEAN ALONG 22N80W TO EASTERN HONDURAS NEAR 15N86W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE FRONT WITH THE MOST CONCENTRATED AREA OF CONVECTION OCCURRING FROM 15N-20N BETWEEN 79W-85W. THE FRONT IS SUPPORTED BY AN UPPER LEVEL SHORTWAVE TROUGH LOCATED OVER THE MID-ATLANTIC STATES AND FAR W ATLC WATERS. SOUTH OF THIS UPPER LEVEL TROUGHING...AN UPPER LEVEL RIDGE EXTENDS FROM NORTHERN COLOMBIA TO THE NW CARIBBEAN WITH ANTICYCLONIC FLOW COVERING MUCH OF THE WESTERN CARIBBEAN W OF 70W. UPPER LEVEL DIFFLUENCE OVER PORTIONS OF CENTRAL AMERICA IS GENERATING ISOLATED S OF 11N BETWEEN 75W-80W. THE REMAINDER OF THE CARIBBEAN IS UNDER THE INFLUENCE OF AN EXITING UPPER LEVEL TROUGH E OF 65W. THE UPPER LEVEL TROUGH AXIS IS ALONG 62W... WITH SCATTERED SHOWERS OCCURRING OVER THE NE CARIBBEAN N OF 16N E OF 67W. ATLANTIC OCEAN... AN UPPER LEVEL SHORTWAVE TROUGH IS ACROSS THE MID-ATLANTIC STATES AND EXTENDS INTO THE FAR W ATLC WATERS W OF 76W. THIS TROUGH SUPPORTS A 992 MB LOW IS CENTERED NORTH OF THE AREA NEAR 34N77W WITH A COLD FRONT EXTENDING SOUTHWARD ALONG 30N77W 23N79W AND ACROSS CENTRAL CUBA INTO THE NW CARIBBEAN SEA. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 120 NM E OF THE FRONT. FARTHER E...A 1005 MB LOW IS CENTERED NEAR 28N66W AND IS SUPPORTED BY AN UPPER LEVEL SHORTWAVE TROUGH WITH AXIS EXTENDING FROM 30N63W TO 18N60W. UPPER LEVEL DIFFLUENCE E OF THE TROUGH AXIS IS GENERATING SCATTERED SHOWERS COVERING AN AREA FROM 19N-31N BETWEEN 58W-65W. ANOTHER AREA OF SCATTERED SHOWERS AND ISOLATED TSTMS INFLUENCED BY THE UPPER LEVEL DIFFLUENCE IS AN AREA FROM 25N-32N BETWEEN 51W-57W. ELSEWHERE ACROSS THE REMAINDER OF THE CENTRAL AND EASTERN ATLC A SURFACE RIDGE DOMINATES ANCHORED ON A 1019 MB HIGH CENTERED NEAR 33N33W. AN UPPER LEVEL RIDGE WITH AXIS ALONG 50W SUPPORTS THE SURFACE RIDGE. $$ HUFFMAN