000 AXNT20 KNHC 042342 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST THU DEC 04 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 CENTERED ALONG 7N12W 3N30W 6N45W INTO FRENCH GUIANA AND SURINAME. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 200 NM SOUTH OF AXIS BETWEEN 27W-34W. SIMILAR CONVECTIVE ACTIVITY IS OVER LIBERIA AND NEAR 5N13W. ...DISCUSSION... GULF OF MEXICO... STRONG SOUTHWESTERLY FLOW ALOFT COVERS THE GULF REGION AND THE FLORIDA PENINSULA...AS A DEEP LAYERED TROUGH MOVES EASTWARD OVER THE E CONUS. THE ATTENDANT COLD FRONT IS MOVING SOUTHEASTWARD ACROSS THE GULF...STRETCHING FROM THE FLORIDA PANHANDLE TO A 1018 MB SFC LOW LOCATED NEAR 24N95W. AT THIS POINT...THE FRONT CONTINUES SW ENTERING MEXICO JUST SOUTH OF TAMPICO WHICH IS CURRENTLY REPORTING GUSTY WINDS UP TO 28 KT. LOW LEVEL CONVERGENCE IN THE VICINITY OF THIS COLD FRONT...COMBINED WITH ATMOSPHERIC LIFT IN MOIST SOUTHWESTERLY FLOW ALOFT...IS SUPPORTING SCATTERED SHOWERS AND ISOLATED TSTMS ALONG THE FRONTAL BOUNDARY. AN EARLIER ASCAT PASS INDICATED NLY WINDS OF 20 TO 30 KT BEHIND THE FRONT. A RELATIVELY COOLER AND DRIER AIRMASS IS NOTED IN THE WAKE OF THE COLD FRONT. OVER THE SW GULF...A SURFACE TROUGH RUNS FROM 21N95W TO 19N93W AND IS GENERATING SOME SHOWER ACTIVITY OVER THE BAY OF CAMPECHE. SUBSIDENCE AND RESULTANT DRY AIR IS INHIBITING DEEP CONVECTION OVER THE SE GULF...WHERE GENERALLY FAIR WEATHER PREVAILS. OVER THE NEXT DAY...THE COLD FRONT IS FORECAST TO CONTINUE MOVING SOUTHEASTWARD OVER THE GULF...BUT IS EXPECTED TO SLOW ITS PROGRESS AS THE STRONGEST UPPER LEVEL ENERGY LIFTS NORTHEAST OF THE GULF REGION. ADDITIONALLY...STRONG N SURFACE WINDS ARE FORECAST TO BLOW THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING IN A GAP WIND EVENT WITH GALE FORCE IN THE EAST PACIFIC REGION BEGINNING LATE TONIGHT. CARIBBEAN SEA... A STATIONARY FRONT EXTENDING OVER CENTRAL CUBA AND THE NW CARIBBEAN SHOULD DISSIPATE TONIGHT. ISOLATED SHOWERS ARE ALONG THE FRONTAL BOUNDARY. A SFC TROUGH IS ALONG 77W SOUTH OF 17N...AND IS FORECAST TO MOVE INLAND OVER CENTRAL AMERICA TONIGHT AND EARLY FRI. A 1010 MB LOW HAS DEVELOPED OVER THE SW CARIBBEAN CLOSE TO 9N80W. THE CLOUD PATTERN IS EXHIBITING SOME CYCLONIC CIRCULATION WITH SCATTERED MODERATE CONVECTION NEAR THE LOW CENTER. PUERTO LIMON IN COSTA RICA HAS REPORTED OCCASIONALLY HEAVY RAIN. ALOFT...AN UPPER-LEVEL HIGH IS CENTERED SOUTH OF THE EASTERN TIP OF DOMINICAN REPUBLIC NEAR 16N68W...WITH AN UPPER RIDGE COVERING THE E AND CENTRAL CARIBBEAN INCLUDING THE LESSER ANTILLES. UPPER LEVEL DIFFLUENCE SW OF THE UPPER HIGH IS SUPPORTING CONVECTION OVER THE SW CARIBBEAN. STRONG SWLY UPPER LEVEL FLOW IS NOTED ACROSS N CENTRAL AMERICA...THE NW CARIBBEAN AND CUBA. THESE WINDS ARE ADVECTING MID/UPPER LEVEL MOISTURE FROM THE EPAC INTO THE CARIBBEAN SEA. PATCHES OF LOW LEVEL MOISTURE CARRIED BY THE TRADE WINDS CONTINUE TO MOVE ACROSS THE EASTERN CARIBBEAN PRODUCING INTERVALS OF CLOUDINESS AND A FEW SHOWERS. ATLANTIC OCEAN... SW TO W WINDS ALOFT CONTINUES TO INCREASE OVER THE W ATLC AS THE DEEP LAYERED TROUGH OVER THE E CONUS PROGRESSES EASTWARD. A SURFACE TROUGH IS E OF THE FLORIDA PENINSULA ALONG 80W FROM 26N TO 30N. MAINLY LOW TOPPED CLOUDS ARE NEAR THE TROUGH. FARTHER TO THE E...A COLD FRONT ENTERS THE FORECAST AREA NEAR 31N57W THEN CONTINUES SW TO THE CENTRAL BAHAMAS WHERE IT BECOMES STATIONARY. 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 BERMUDA AND A SHARP UPPER-LEVEL TROUGH N OF 14N BETWEEN 30W-50W. A JET STREAM BRANCH WITH CORE WINDS OF 70-90 KT IS JUST AHEAD OF THE TROUGH AXIS AND GOES FROM 20N39W TO BEYOND 33N35W. THIS UPPER TROUGH IS ASSOCIATED WITH A SURFACE TROUGH EXTENDING FROM A 1011 MB SURFACE LOW NEAR 28N48W TO 31N45W TO ANOTHER 1011 MB SURFACE LOW SITUATED NEAR 26N43W TO 21N46W. A WELL DEFINED SWIRL OF LOW CLOUDS IS ASSOCIATED WITH THE FIRST SFC LOW WHILE THE SECOND ONE IS DISSIPATING. OVER THE E ATLC...SUBSIDENCE AND FAIR WEATHER PREVAIL THANKS TO A SURFACE RIDGE EXTENDING FROM A 1027 MB HIGH LOCATED AROUND MIDWAY BETWEEN THE AZORES AND THE MADEIRA ISLANDS. FARTHER TO THE S...AN UPPER-LEVEL HIGH CENTERED JUST SOUTH OF THE CAPE VERDE ISLANDS EXTENDS A RIDGE NWD OVER THE DISCUSSION AREA. $$ GR.