000 AXNT20 KNHC 082351 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST THU DEC 08 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 2345 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH REMAINS INLAND ACROSS AFRICA EXTENDING ACROSS THE COUNTRIES OF GHANA...COTE D' IVOIRE...AND LIBERIA. THE ITCZ ENTERS THE ATLC WATERS ACROSS THE COAST OF SIERRA LEONE NEAR 8N13W...CONTINUING WESTWARD ALONG 6N20W 5N30W 6N40W TO 3N47W. SCATTERED MODERATE CONVECTION IS FROM 3N-8N BETWEEN 20W-43W. ...DISCUSSION... GULF OF MEXICO... FAIR WEATHER CONDITIONS ARE PRESENT ACROSS THE GULF THIS EVENING...INFLUENCED BY A 1029 MB RIDGE OF HIGH PRESSURE CENTERED OVER WRN MISSISSIPPI. DESPITE THE BENIGN WEATHER...A GREAT PORTION OF THE BASIN IS COVERED BY OVERCAST LOW LEVEL STRATOCUMULUS CLOUDS OBSERVED ON VISIBLE IMAGERY. WATER VAPOR IMAGERY SHOWS DRY MID-UPPER LEVEL SOUTHWESTERLY WIND FLOW COVERS THE DISCUSSION AREA. WEATHER CONDITIONS ARE EXPECTED TO REMAIN CONSTANT OVER THE NEXT 24 HOURS. CARIBBEAN SEA... A WEAKENING STATIONARY FRONT ENTERS THE NW CARIBBEAN ACROSS WRN CUBA AND EXTENDING SW TO CENTRAL AMERICA ALONG 22N82W 19N85W 16N88W. ISOLATED SHOWERS ARE WITHIN 40 NM ON EITHER SIDE OF THE BOUNDARY. AN UPPER LEVEL LOW IS LOCATED ABOUT 230 NM NE OF PUERTO RICO. A WEAK NARROW UPPER TROUGH EXTENDS SW FROM THE UPPER LOW TO THE SW CARIBBEAN PUSHING A VERY DRY AND STABLE AIRMASS ALOFT TO MOST OF THE DISCUSSION AREA...EXCEPT THE SE AND S-CENTRAL CARIBBEAN. AN UPPER ANTICYCLONE CENTERED OVER THE ERN TROPICAL ATLC IS PROVIDING MID-UPPER MOISTURE OVER THIS REGION. SCATTERED WEAK SHOWERS ARE OBSERVED IN THE MOIST SECTOR WITHIN 60 NM ON EITHER SIDE OF A LINE EXTENDING FROM 16N51W TO 14N72W. EXPECT THE COLD FRONT TO DISSIPATE OVER THE NEXT 12 HOURS. ATLANTIC OCEAN... A BROAD UPPER TROUGH CONTINUES TO MOVE ACROSS THE WRN ATLC SUPPORTING A COLD FRONT EXTENDING INTO THE AREA ACROSS 32N68W TO THE BAHAMAS NEAR 24N77W WHERE IT BECOMES A WEAK STATIONARY FRONT INTO WRN CUBA ALONG 22N82W. SCATTERED SHOWERS ARE WITHIN 20 NM ON EITHER SIDE OF THE FRONTAL BOUNDARY. OVERCAST LOW LEVEL STRATOCUMULUS CLOUDS ARE W OF THE BOUNDARY TO ACROSS FLORIDA AND INTO THE GULF OF MEXICO. A SURFACE RIDGE OF HIGH PRESSURE COVERS THE REMAINDER WRN HALF OF THE BASIN ANCHORED BY A 1022 MB HIGH CENTERED NEAR 33N57W. AN AREA OF UPPER LEVEL TROUGHINESS EXTENDS SW FROM THE CENTRAL ATLC INTO THE FAR ERN CARIBBEAN SEA... COMPOSED BY TWO UPPER LOWS CENTERED ABOUT 230 NM NE OF PUERTO RICO AND THE OTHER ONE NEAR 28N45W. THIS UPPER LEVEL SYSTEM REFLECTS AT SURFACE AS A LENGTHY TROUGH EXTENDING ALONG 32N45W 24N42W 20N52W 15N60W. MID-UPPER LEVEL DIFFLUENCE IN THE VICINITY OF THE SURFACE TROUGH IS GENERATING A BROAD AREA OF SCATTERED SHOWERS AND THUNDERSTORMS WITHIN 200-250 NM E OF THE SURFACE TROUGH. ACROSS THE REMAINDER OF THE CENTRAL AND ERN BASIN... SURFACE RIDGING ANCHORED BY AN AZORES 1026 MB HIGH NEAR 10N30W AND A 1030 MB HIGH WEST OF PORTUGAL NEAR 40N14W CONTINUES TO INFLUENCE MUCH OF THE EASTERN ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA