000 AXNT20 KNHC 052343 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST FRI DEC 05 2008 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 6N11W 7N22W 5N35W 6N50W INTO FRENCH GUIANA AND SURINAME. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-7N BETWEEN 10W-16W. SIMILAR CONVECTION IS ALSO FOUND WITHIN 100 NM N...AND 60 NM S OF THE ITCZ AXIS BETWEEN 36W-42W. ...DISCUSSION... GULF OF MEXICO... A SHORT-WAVE TROUGH IS OVER THE WESTERN GULF AND EXTENDS FROM SE LOUISIANA TO THE BAY OF CAMPECHE. STRONG SOUTHWESTERLY FLOW IS AHEAD OF THE TROUGH AXIS COVERING THE EASTERN GULF AND THE FLORIDA PENINSULA. THE ATTENDANT FRONTAL SYSTEM TRAILS ACROSS THE GULF REGION...EXTENDING FROM NORTHERN FLORIDA TO 26N90W TO A 1018 MB SURFACE LOW NEAR 21N95W THEN ENTERING MEXICO NEAR JALAPA. A PRE-FRONTAL TROUGH LIES ALONG 94W SOUTH OF 22N TO OVER THE BAY OF CAMPECHE. A RATHER UNIFORM STRATUS CLOUDS COVER THE EASTERN SLOPES OF THE SIERRA MADRE MOUNTAINS. SIMILAR CLOUDINESS ARE ALSO SEEN ALONG THE COAST OF TEXAS. THE FRONT REMAINS NEARLY STATIONARY OVER THE GULF WATERS...BUT A REINFORCING SHOT OF COLD AIR WILL PUSH THIS FEATURE SOUTHWARD OVER THE EASTERN GULF SAT AFTERNOON...REACHING SOUTH FLORIDA LATE SATURDAY/EARLY SUNDAY MORNING...AND WESTERN CUBA SUNDAY AFTERNOON. NLY WINDS OF 15-20 KT ARE NOTED BEHIND THE FRONT...PARTICULARLY OVER THE N-CENTRAL GULF. THESE WINDS ARE ADVECTING A RELATIVELY COOLER AND DRIER AIRMASS ACROSS THE N AND W GULF IN THE WAKE OF THE FRONT. MAINLY ELY WINDS OF 10-15 KT ARE AHEAD OF THE FRONTAL ZONE. IN ADDITION...STRONG N TO NE SURFACE WINDS ARE BLOWING THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE EAST PACIFIC REGION. CARIBBEAN SEA... A SURFACE TROUGH...REMNANTS OF AN OLD FRONTAL BOUNDARY STRETCHES FROM THE CAYMAN ISLANDS ACROSS THE PROVINCE OF CAMAGUEY CUBA TO THE SE BAHAMAS THEN CONTINUES MAINLY EWD ACROSS THE W ATLC TO NEAR 27N 57W. ISOLATED SHOWERS ARE ALONG THE TROUGH AXIS. ANOTHER SFC TROUGH IS OVER THE SW CARIBBEAN AND GOES FROM 13N79W TO 9N81W. ISOLATED SHOWERS ARE ALSO ASSOCIATED WITH THIS FEATURE. ALOFT...AN UPPER RIDGE DOMINATES THE CENTRAL AND EASTERN CARIBBEAN WHILE STRONG SWLY UPPER-LEVEL FLOW IS NOTED ACROSS MOST OF CENTRAL AMERICA AND THE NW CARIBBEAN INTO CUBA AND THE BAHAMAS. THESE WINDS ARE TRANSPORTING SOME MID/UPPER LEVEL MOISTURE FROM THE EPAC REGION INTO THE CARIBBEAN SEA AND WESTERN CUBA WHERE A NARROW BAND OF TRANSVERSE HIGH CLOUDS IS SEEN. PATCHES OF LOW LEVEL MOISTURE...MORE CONCENTRATED SOUTH OF HISPANIOLA CONTINUE TO MOVE ACROSS THE EAST AND CENTRAL CARIBBEAN PRODUCING INTERVALS OF CLOUDINESS AND A FEW SHOWERS. THE TAIL END OF AN UPPER-LEVEL TROUGH EXTENDING OVER THE CENTRAL ATLC IS PRODUCING SOME SHOWER ACTIVITY OVER THE SOUTHERN WINDWARD ISLANDS. ATLANTIC OCEAN... SW TO W WINDS ALOFT CONTINUES TO INCREASE OVER THE W ATLC AS A DEEP LAYERED TROUGH OVER THE E AND S CONUS PROGRESSES SE. THE ASSOCIATED COLD FRONT ENTERS THE FORECAST REGION NEAR 32N76W THEN CONTINUES SW TO N FLORIDA AND BECOMES STATIONARY ACROSS THE GULF OF MEXICO. LOW LEVEL CONVERGENCE IS SUPPORTING ISOLATED SHOWERS WITHIN 60 NM EITHER SIDE OF THE FRONTAL BOUNDARY. E OF THE FRONTAL SYSTEM...THE FLOW ALOFT IS MORE AMPLIFIED...WITH AN UPPER RIDGE AXIS EXTENDING FROM THE NE CARIBBEAN TO BEYOND 31N58W AND AN UPPER-LEVEL TROUGH STRETCHING FROM AN UPPER-LEVEL LOW NEAR 32N44W TO NEAR BARBADOS IN THE SOUTHERN WINDWARD ISLANDS. SCATTERED MODERATE CONVECTION IS NEAR THE TAIL END OF THIS TROUGH AFFECTING THE FAR SE CARIBBEAN...THE SOUTHERN WINDWARD ISLANDS AND NE VENEZUELA. MODERATE TO STRONG UPPER- LEVEL SUBSIDENCE AND IMPLIED DRY AIR MASS IS NOTED OVER MUCH OF THE W AND CENTRAL ATLC NORTH OF THE AFOREMENTIONED UPPER-LEVEL TROUGH. THIS UPPER FEATURE IS ASSOCIATED WITH A SURFACE TROUGH EXTENDING FROM A 1011 MB SURFACE LOW NEAR 27N48W TO 26N45W TO 23N49W. A WELL DEFINED SWIRL OF LOW CLOUDS REMAINS ASSOCIATED WITH THE SFC LOW WHILE SCATTERED SHOWERS ARE JUST AHEAD OF THE SFC TROUGH MAINLY FROM 26N TO 29N. FARTHER SOUTH...THERE IS ANOTHER SFC TROUGH THAT RUNS FROM 19N43W TO 10N48W. LOW/MID CLOUDS WITH ISOLATED SHOWERS ARE WITHIN 300 NM E OF THE TROUGH AXIS WHILE A CLUSTER OF MODERATE CONVECTION IS WEST OF THE TROUGH NEAR 13N49W. A BROAD UPPER-LEVEL HIGH CENTERED NEAR 8N23W DOMINATES MOST OF THE TROPICS AND IS ENHANCING CONVECTION ALON THE ITCZ. NUMEROUS SHOWERS AND SCATTERED TSTMS ARE AHEAD OF AN UPPER-LEVEL LOW SPINNING OVER THE E ATLC NEAR 25N28W. $$ GR