000 AXNT20 KNHC 112322 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SUN DEC 11 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2245 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA ENTERING THE E TROPICAL ATLC NEAR 14N17W TO 10N19W. THE ITCZ CONTINUES FROM 10N19W ALONG 7N26W 5N38W TO 1N47W. NO SIGNIFICANT CONVECTION IS NOTED. ...DISCUSSION... GULF OF MEXICO... AN UPPER TROUGH IS OVER THE E CONUS WITH A SHORTWAVE UPPER TROUGH OVER THE LOWER MISSISSIPPI VALLEY USHERING MID/UPPER LEVEL MOISTURE OVER MISSISSIPPI TO GEORGIA AND SOUTH CAROLINA WITH SCATTERED TO HEAVY RAINS ACROSS THE S PORTIONS OF MISSISSIPPI...ALABAMA...GEORGIA...AND THE FLORIDA PANHANDLE WITH SCATTERED SHOWERS IN THE NE GULF MAINLY N OF 27N E OF 88W. THE REMAINDER OF THE GULF UPPER LEVELS ARE NEAR ZONAL WESTERLY FLOW. STRONG SURFACE RIDGE DOMINATES THE GULF AND ANCHORED BY A 1038 MB HIGH OVER NEW ENGLAND. EASTERLY SURFACE FLOW COUPLED WITH LOW LEVEL MOISTURE IS GIVING THE REMAINDER OF THE GULF MOSTLY CLOUDY SKIES WITH PATCHES OF SCATTERED SHOWERS. SURFACE RIDGE WILL SHIFT BEGIN TO SHIFT E ON WED THROUGH FRI ALLOWING RETURN FLOW OVER THE W GULF TO SPREAD EASTWARD. THE NEXT COLD FRONT WILL STALL OVER THE TEXAS COAST THU NIGHT AND DRIFT WELL W OF AREA ON FRI. CARIBBEAN SEA... WEAK PRESSURE PATTERN DOMINATES THE CARIBBEAN THIS EVENING. A BROAD UPPER RIDGE AXIS EXTENDS FROM SOUTH AMERICA OVER COLOMBIA NEAR 11N73W NW TO W CUBA NEAR THE ISLE OF YOUTH GIVING THE E CARIBBEAN MOSTLY WESTERLY FLOW ALOFT. THIS UPPER RIDGE IS DRAWING TROPICAL MOISTURE N OVER THE S/CENTRAL CARIBBEAN AND COUPLED WITH THE MONSOON TROUGH THAT EXTENDS FROM COLOMBIA NEAR 11N74W ACROSS PANAMA/COSTA RICA NEAR 9N83W INTO THE E PACIFIC REGION ARE GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 15N BETWEEN 75W-84W. THE REMAINDER OF THE CARIBBEAN IS UNDER MOSTLY FAIR CONDITIONS THIS EVENING WITH THE POSSIBLE ISOLATED LOW LEVEL SHOWER USHERED IN ON THE EASTERLY TRADE WINDS. THE RIDGE OVER THE W ATLC WILL TIGHTEN THE PRESSURE GRADIENT LATER IN THE WEEK INCREASING TRADE WINDS. ATLANTIC OCEAN... THE BROAD UPPER TROUGH OVER THE E CONUS EXTENDS INTO THE NW ATLC SUPPORTING A WEAKENING COLD FRONT THAT ENTERS THE W ATLC AT 12/2100 UTC NEAR 32N67W TO 29N76W. THE BROAD UPPER RIDGE OVER THE CARIBBEAN COVERS THE REMAINDER OF THE W ATLC WITH STRONG SUBSIDENCE AND DRY STABLE AIR SE OF THE ABOVE FRONT W OF 60W...THIS LIMITING SHOWER ACTIVITY OVER THE AREA. A BROAD ELONGATED UPPER LOW IS OVER THE CENTRAL ATLC EXTENDING FROM 28N60W THROUGH 23N56W TO 20N50W SUPPORTING A SURFACE TROUGH ANALYZED FROM 27N62W TO 20N61W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 175/200 NM OF LINE FROM 18N48W TO 27N58W. BROAD UPPER RIDGE RIDGE IS ANCHORED N OF THE DISCUSSION AREA NEAR 33N41W COVERING THE REMAINDER OF THE CENTRAL AND THE E ATLC WITH A SURFACE RIDGE COVERING THE E ATLC ANCHORED BY A 1032 MB HIGH N OF THE DISCUSSION AREA ABOUT 400 NM SW OF THE AZORES. THE W ATLC SURFACE RIDGE WILL BUILD E BY TUE AS A NEW COLD FRONT FORMS ALONG 65W THEN THE FRONT WILL SHIFT INTO THE CENTRAL ATLC THROUGH FRI STRENGTHENING THE RIDGE OVER THE W ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW