000 AXNT20 KNHC 191049 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST TUE DEC 19 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA... CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA... NORTHEASTERN SECTIONS OF SOUTH AMERICA...AND THE 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 1015 UTC. ...THE ITCZ... ITCZ AXIS IS ALONG 7N10W 5N26W 4N45W 3N52W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM THE EQUATOR TO THE COAST OF AFRICA E OF 8W ACROSS THE PRIME MERIDIAN. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 1N-10N BETWEEN 35N-50W. ...DISCUSSION... GULF OF MEXICO... MID/UPPER LEVEL SHORTWAVE TROUGH IS OVER THE CENTRAL GULF FROM THE FLORIDA PANHANDLE TO THE YUCATAN PENINSULA. THIS UPPER TROUGH IS EMBEDDED WITHIN A BROAD UPPER RIDGE THAT COVERS THE E US AND GULF OF MEXICO INTO THE W ATLC. A 1018 MB LOW IS DEVELOPING IN THE W GULF NEAR 26N94W ALONG THE SURFACE TROUGH THAT EXTENDS ALONG 94W FROM 24N-29N. SCATTERED SHOWERS ARE N OF 25N FROM 90W-97W. AN UPPER TROUGH FROM OVER THE W ATLC EXTENDS ACROSS THE FLORIDA PENINSULA INTO THE SE GULF E OF 82W. THE NEXT COLD FRONT IS EXPECTED TO MOVE OFF THE TEXAS COAST ON WED NIGHT/THU BRINGING SOME SHOWER ACTIVITY TO THE NW CORNER OF THE GULF THEN MOVING EASTWARD. A THIN LINE OF ISOLATED SHOWERS ARE OVER THE SE GULF ALONG 23N87W THROUGH THE STRAITS OF FLORIDA INCLUDING THE FLORIDA KEYS TO 25N80W. CARIBBEAN SEA... UPPER TROUGH FROM THE W ATLC DIPS S INTO THE W CARIBBEAN TO 16N FROM 68W-82W BRINGING VERY DRY UPPER AIR AND STRONG SUBSIDENCE ACROSS CUBA...JAMAICA...AND THE CAYMAN ISLANDS WITH MODERATE SUBSIDENCE ALREADY IN PLACE OVER THE REMAINDER OF THE W CARIBBEAN. THIS IS GIVING THE AREA SHOWER FREE CONDITIONS. BROAD UPPER RIDGE COVERS THE REMAINDER OF THE CARIBBEAN E OF 68W ADVECTING TROPICAL ACROSS THE AREA COUPLED WITH THE DIFFLUENCE OVER THE SAME AREA ARE GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 14N-19N BETWEEN 66W-73W. MODERATE TRADE WINDS DOMINATE THE ENTIRE CARIBBEAN. ATLANTIC OCEAN... BROAD UPPER RIDGE EXTENDS FROM THE E US OVER THE NW ATLC W OF 50W WITH AN UPPER LEVEL LOW OVER THE S BAHAMA ISLANDS NEAR 22N72W COVERING THE SW ATLC S OF 27N FROM 65W-82W DIPPING INTO THE W CARIBBEAN. A SURFACE REFLECTION IN THE FORM OF A SURFACE TROUGH EXTENDS FROM 24N66W INTO THE CARIBBEAN ACROSS HAITI TO 15N76W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 20N-24N BETWEEN 62W-72W. BROAD SURFACE RIDGE COVERS THE REMAINDER OF THE W ATLC WITH A 1025 AND 1024 MB HIGHS LOCATED NEAR 32N73W AND 30N58W RESPECTIVELY. DEEP LAYERED TROUGH IS OVER THE E/CENTRAL ATLC EXTENDING FROM AN UPPER LOW NEAR 29N34W SW TO NEAR 19N42W. THE ASSOCIATED COLD FRONT ENTERS THE REGION NEAR 32N36W TO NEAR 29N37W WHERE IT DISSIPATES TO 22N47W. A PRE-FRONTAL TROUGH EXTENDS FROM 31N33W ALONG 24N37W TO 19N43W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ASSOCIATED WITH THE UPPER LOW N OF 27N FROM 30W-37W. AN UPPER RIDGE IS OVER THE E ATLC FROM 6N17W ALONG 22N21W TO BEYOND 32N22W WITH ENOUGH DIFFLUENCE TO THE W TO GENERATE SCATTERED SHOWERS/THUNDERSTORMS WELL E OF THE COLD FRONT WITHIN 120/150 NM OF LINE FROM 22N30W TO 28N27W AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 27N FROM 22W-30W. $$ WALLACE