000 AXNT20 KNHC 102347 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST WED DEC 10 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 IS CENTERED ALONG 8N13W 4N21W 7N35W 9N53W 7N59W. A SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ ALONG 54W/55W SOUTH OF 13N. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS NOTED WITHIN 360 NM E OF THIS TROUGH. THE CLOUD PATTERN IS STILL EXHIBITING SOME CYCLONIC TURNING ALONG THE TROUGH AXIS NEAR 9.5N...WHERE SCATTERED SHOWERS ARE SEEN. A DIFFLUENT PATTERN ALOFT IS HELPING TO INDUCE ALL THIS CONVECTIVE ACTIVITY. ELSEWHERE...SCATTERED MODERATE CONVECTION IS FROM 5N-8N BETWEEN 16W-20W. SIMILAR CONVECTION IS NEAR 7N46W...AND NEAR 9N43W. ...DISCUSSION... GULF OF MEXICO... A STRONG COLD FRONT IS CURRENTLY MOVING ACROSS THE GULF WATERS. A CUT-OFF LOW OVER EASTERN TEXAS AND THE NW GULF SUPPORTS THIS FRONT. AS OF 2100 UTC...THE FRONT EXTENDS FROM A 1009 MB LOW LOCATED NEAR 29N88W ACROSS THE CENTRAL GULF TO THE EASTERN PORTION OF THE BAY OF CAMPECHE INTO THE ISTHMUS OF TEHUANTEPEC TO NEAR 17N96W. A ROPE CLOUD DELINEATES THE LEADING EDGE OF THE FRONT WHILE CLOUDINESS ASSOCIATED WITH THE FRONTAL BOUNDARY COVERS MOST OF THE WESTERN GULF. IN ADDITION...COLD AIR HAS PENETRATED INTO THE SIERRA MADRE MOUNTAINS AS DEPICTED BY A RATHER UNIFORM STRATUS CLOUDS COVER AND STATIONARY FRONT IS ANALYZED FROM 17N96W TO 21N100W. AHEAD OF THE COLD FRONT...S TO SE SURFACE WINDS OF 20 TO 30 KT CONTINUE TO ADVECT LOW LEVEL MOISTURE ACROSS PORTIONS OF THE E AND CENTRAL GULF WHERE SCATTERED MODERATE CONVECTION IS FOUND MAINLY N OF 26N. SHOWERS AND TSTMS ARE ALSO AFFECTING THE SE CONUS...PARTICULARLY SOUTH CAROLINA...GEORGIA AND THE FLORIDA PANHANDLE WITH THE THREAT OF SEVERE STORMS. IN THE WAKE OF THE COLD FRONT...INCREASED NW TO N SURFACE WINDS ARE PRESENT. AN EARLIER ASCAT PASS SHOWED NLY WINDS OF 20 TO 30 KT BEHIND THE FRONT. PRESENTLY...SURFACE DATA INDICATES GALE FORCE WINDS OF 35 KT OVER THE SW PORTION OF THE GULF WHERE A GALE WARNING IS IN EFFECT. THE CITIES OF VERACRUZ AND MINATITLAN IN SE MEXICO ARE ALSO REPORTING GUSTY WINDS UP TO 45 KT. A RELATIVELY COOLER AIRMASS FOLLOWS THE FRONT WITH A 1030 MB HIGH OVER THE STATE OF CHIHUAHUA MEXICO. ADDITIONALLY... STRONG NW TO N SURFACE WINDS ARE FORECAST TO BLOW THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE E PACIFIC REGION BEGINNING AT 11/0600 UTC. THE COLD FRONT WILL CONTINUE TO MOVE ACROSS THE GULF OF MEXICO TONIGHT EXTENDING FROM THE FLORIDA PANHANDLE TO THE YUCATAN PENINSULA LATE TONIGHT...AND CROSSING SOUTH FLORIDA AND WESTERN CUBA THU MORNING. CARIBBEAN SEA... STRONG SURFACE HIGH PRES LOCATED NORTH OF THE AREA COMBINED WITH THE COLOMBIAN/PANAMANIAN LOW IS PRODUCING STRONG TRADE WINDS ACROSS THE BASIN. THESE WINDS ARE EXPECTED TO DIMINISH FROM W TO E THROUGH THU AS HIGH PRES SHIFTS E AHEAD OF ADVANCING COLD FRONT WHICH IS CURRENTLY MOVING ACROSS THE GULF WATERS. ACCORDING TO THE COMPUTER MODELS...THE COLD FRONT WILL BE OVER WESTERN CUBA AND THE NW CARIBBEAN THU MORNING EXTENDING FROM CENTRAL CUBA AND THE CAYMAN ISLANDS TO HONDURAS LATE IN THE AFTERNOON. TYPICAL PATCHES OF LOW LEVEL MOISTURE...CARRIED BY THE TRADE WINDS ARE MOVING ACROSS THE E-CENTRAL CARIBBEAN PRODUCING INTERVALS OF PASSING SHOWERS AND CLOUDS FROM THE LEEWARD ISLANDS TO JAMAICA INCLUDING THE UK/US VIRGIN ISLANDS AND PUERTO RICO AS WELL AS HISPANIOLA. IN THE UPPER-LEVELS... BROAD ANTICYCLONIC FLOW...AROUND AN UPPER HIGH OVER N SOUTH AMERICA...DOMINATES THE ENTIRE BASIN. MID/UPPER-LEVEL MOISTURE CONTINUES STREAMING ACROSS PANAMA AND COSTA RICA INTO THE SW CARIBBEAN IN SOUTHERLY FLOW ALOFT W OF THE UPPER HIGH. ATLANTIC OCEAN... THE ENTIRE FORECAST REGION IS UNDER THE INFLUENCE OF A STRONG 1043 MB SURFACE HIGH LOCATED NEAR 41N41W. THIS SYSTEM IS PRODUCING A SWATH OF MODERATE TO STRONG ELY WINDS OF 20 TO 25 KT ACROSS THE ATLANTIC OCEAN PARTICULARLY N OF 24N...AND IS GENERALLY SUPPORTING FAIR WEATHER ACROSS THE AREA. THIS HIGH PRES SYSTEM WILL CONTINUE TO SHIFT EWD ALLOWING A COLD FRONT TO MOVE OFF THE FLORIDA COAST THU NIGHT. GALE FORCE WINDS ARE EXPECTED AHEAD OF THIS FRONT TOMORROW OVER THE SW N ATLC MAINLY NORTH OF THE NORTHERN BAHAMAS AND WEST OF 72W. MOIST SOUTHWESTERLY FLOW ALOFT CONTINUES TO INCREASE OVER THE W ATLC AS A DEEP LAYERED TROUGH OVER THE CENTRAL CONUS AND N MEXICO CONTINUES PROGRESSING EASTWARD. THIS TROUGH SUPPORTS THE ABOVE MENTIONED COLD FRONT. A FEW SHOWERS ARE NEAR A DISSIPATING FRONTAL BOUNDARY N OF 27N BETWEEN 43W AND 50W. AN UPPER-LEVEL LOW SPINNING OVER THE E ATLC NEAR 25N28W IS ALSO GENERATING SCATTERED SHOWERS N OF 20N BETWEEN 20N-30W. ACROSS THE TROPICAL ATLC...GENERALLY WESTERLY FLOW ALOFT IS PRESENT E OF 45W WHILE A SHORT WAVE TROUGH LIES ALONG 50W/51W WITH AXIS EXTENDING SOUTH INTO THE GUYANAS. $$ GR