000 AXNT20 KNHC 090548 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST FRI DEC 09 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 1115 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS A PORTION OF AFRICA WITH THE ITCZ AXIS ENTERING THE E TROPICAL ATLC NEAR 8N13W CONTINUING ALONG 5N22W 7N37W TO 4N47W. CLUSTERS OF SCATTERED MODERATE/ STRONG CONVECTION ARE WITHIN 150/180 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 14W-43W. ...DISCUSSION... GULF OF MEXICO... ZONAL SW FLOW ALOFT DOMINATES THE GULF WITH STRONG SUBSIDENCE AND DRY STABLE AIR ALOFT COVERING THE GULF SE OF A LINE FROM THE BIG BEND AREA OF FLORIDA TO TAMPICO MEXICO. A SURFACE RIDGE COVERS THE GULF ANCHORED BY A 1026 MB HIGH OVER CENTRAL TENNESSEE AND A 1028 MB HIGH OVER E MARYLAND. IN SPITE OF THE DRY AIR ALOFT...MOSTLY OVERCAST LOW STRATOCUMULUS CLOUDS COVER THE GULF WITH POSSIBLE ISOLATED SHOWERS. SURFACE RIDGE WILL BUILD OVER THE US CONUS FRI THROUGH SUN ALLOWING SOME INCREASE IN WINDS AND SEAS ACROSS THE REGION. CARIBBEAN SEA... A DISSIPATING STATIONARY FRONT ENTERS THE W CARIBBEAN FROM THE W ATLC ACROSS CUBA NEAR COLON INTO THE GULF OF HONDURAS AND THE COAST NEAR GUATEMALA/HONDURAS. ISOLATED SHOWERS ARE W OF THE FRONT TO THE YUCATAN PENINSULA. A VERY BROAD LOW AMPLITUDE UPPER RIDGE COVERS CARIBBEAN INTO THE TROPICAL ATLC GIVING THE CARIBBEAN SW TO W FLOW ALOFT. STRONG SUBSIDENCE AND DRY STABLE AIR COVERS THE CARIBBEAN N OF LINE FROM THE N LEEWARD ISLANDS NEAR 17N63W ALONG 15N75W TO NICARAGUA NEAR 13N84W. HOWEVER... EASTERLY SURFACE FLOW IS USHERING IN LOW LEVEL MOISTURE TO GENERATE CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 19N BETWEEN 73W-85W. BAND OF SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS CONTINUE TO STREAM EASTWARD WITHIN 90/120 NM OF LINE FROM 14N70W ACROSS THE LESSER ANTILLES NEAR 15N61W. THE FRONT WILL DISSIPATE FROM W CUBA TO THE GULF OF HONDURAS OVERNIGHT. THE SURFACE TROUGH E OF THE LESSER ANTILLES WILL PIVOT WEST AND DISSIPATE THROUGH EARLY FRI. A SECOND TROUGH WILL MOVE W THROUGH THE LEEWARD ISLANDS SUN AND MON. ATLANTIC OCEAN... A COLD FRONT EXTENDS ACROSS THE NW ATLC TO 31N69W WHERE IT BECOMES STATIONARY ACROSS THE DISCUSSION AREA ALONG 26N75W TO OVER THE N BAHAMA ISLANDS WHERE IT BEGINS TO DISSIPATE AS IT CROSSED CUBA NEAR COLON INTO THE W CARIBBEAN. BROKEN/OVERCAST LOW/MID CLOUDS WITH ISOLATED SHOWERS ARE W OF THE FRONT. AN E/W ELONGATED UPPER LOW IS IN THE SW ATLC ROUGHLY CENTERED NEAR 22N64W COVERING THE AREA FROM 18N-15N BETWEEN 53W-75W AND GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 19N-22N BETWEEN 57W-64W. A SECOND MORE SYMMETRICAL UPPER LOW IS IN THE CENTRAL ATLC NEAR 26N46W SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 32N45W ALONG 28N42W 22N45W INTO THE TROPICS NEAR 20N52W 17N58W TO E OF THE LESSER ANTILLES NEAR 15N60W. AN UPPER TROUGH IS IN THE E ATLC N OF 27N E OF 30W. A VERY BROAD LOW AMPLITUDE UPPER RIDGE COVERS THE TROPICS S OF 20N BETWEEN 30W-80W AND FROM 20N-25N BETWEEN THE CENTRAL ATLC UPPER LOW AND E ATLC UPPER TROUGH GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 200 NM E OF THE CENTRAL ATLC SURFACE TROUGH AND FROM 22N-27N BETWEEN 30W-38W. A SURFACE RIDGE DOMINATES THE E ATLC ANCHORED BY A SERIES OF HIGHS N OF THE DISCUSSION AREA. THE STATIONARY FRONT WILL WEAKEN AND START TO SHIFT W FRI STALLING FROM 31N75W TO 23N81W BY LATE FRI. A COLD FRONT MOVING OFF THE GEORGIA COAST SAT WILL OVERTAKE THE CURRENT FRONT THEN WILL STALL FROM 31N72W TO CENTRAL FLORIDA BY LATE SAT. A SURFACE TROUGH WILL MOVE W FROM THE CENTRAL ATLC TO BETWEEN PUERTO RICO AND BERMUDA LATE SUN AND MON. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW