000 AXNT20 KNHC 251731 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST TUE NOV 25 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1745 UTC. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 8N13W 4N30W 5N45W 4N53W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE ALONG THE ITCZ AXIS. SCATTERED MODERATE CONVECTION IS NEAR 4N12W. ...DISCUSSION... GULF OF MEXICO... A COLD FRONT IS MOVING ACROSS THE GULF REGION AND EXTENDS FROM NORTHERN FLORIDA ALONG 25N90W TO NE MEXICO NEAR 25N98W. A DEEP-LAYERED TROUGH OVER THE EASTERN CONUS DIGGING INTO THE GULF REGION SUPPORTS THIS FRONT THAT IS FORECAST TO APPROACH LAKE OKEECHOBEE THIS EVENING AND BE NEAR THE STRAITS OF FLORIDA BY WEDNESDAY MORNING. IN THE WAKE OF THE COLD FRONT...A REINFORCING COOLER AND DRIER AIRMASS IS IN PLACE SUPPORTED BY A 1031 MB SURFACE HIGH OVER NE MEXICO NEAR 28N100W. THIS NEW SURGE OF COLD AIR ALONG THE EASTERN SLOPES OF THE SIERRA MADRE MOUNTAINS IS PRODUCING A GAP WIND EVENT ACROSS THE GULF OF TEHUANTEPEC WITH WINDS CURRENTLY REACHING GALE FORCE PER A RECENT QSCAT PASS. MAINLY LOW/MID CLOUDS ARE ASSOCIATED WITH THE FRONTAL BOUNDARY. THE MOSAIC DOPPLER RADAR FROM THE SE U.S. SHOWS A NARROW LINE OF SHOWERS MOVING ACROSS THE TAMPA BAY AREA. SIMILAR CONVECTION IS ALSO SEEN NEAR 25N97W. ADDITIONALLY...A WEAK 1017 MB HIGH IS OVER CENTRAL FLORIDA. THIS FEATURE WILL DISSIPATE ALLOWING THE FRONT TO MOVE SE ACROSS THE FLORIDA PENINSULA THE REST OF TODAY. NE WINDS OF 15-20 KT ARE BLOWING BEHIND THE COLD FRONT. THESE WINDS WILL VEER TO THE E AND THEN SE AS HIGH OVER NE MEXICO MOVES MAINLY EWD ACROSS THE N GULF STATES THIS AFTERNOON INTO WED. CARIBBEAN SEA... MAIN WEATHER FEATURE CONTINUE TO BE THE BROAD AREA OF LOW PRES LOCATED OVER THE SW CARIBBEAN. A 1007 MB SURFACE LOW IS ANALYZED NEAR 11N82W. LOW LEVEL CONVERGENCE NEAR THIS SURFACE LOW IS SUPPORTING NUMEROUS SHOWERS AND THUNDERSTORMS S OF 16N W OF 75W. MOST THE CONVECTION IS N AND E OF THE LOW CENTER. THIS SYSTEM REMAINS POORLY ORGANIZED AND FURTHER DEVELOPMENT...IF ANY...IS EXPECTED TO BE SLOW TO OCCUR. AS THIS SYSTEM DRIFTS WWD...IT WILL LIKELY PRODUCE HEAVY RAINS AND LOCALIZED FLOODING OVER PORTIONS OF PANAMA...COSTA RICA... NICARAGUA...AND EASTERN HONDURAS DURING THE NEXT COUPLE OF DAYS. PRESSURE GRADIENT BETWEEN THE SURFACE LOW AND A RIDGE N OF AREA IS SUPPORTING N TO NE SURFACE WINDS OF 20 TO 30 KT FOR LOCATIONS IN THE SW CARIBBEAN BUT THESE WINDS ARE EXPECTED TO DIMINISH TONIGHT INTO WED AS RIDGE N OF AREA WEAKENS. MODERATE TRADE WINDS OF 15 TO 20 KT ARE NOTED OVER THE REMAINDER OF THE BASIN. A DIFFLUENT PATTERN ALOFT...ASSOCIATED WITH AN UPPER-LEVEL RIDGE WHICH DOMINATES MOST OF THE REGION...CONTINUES TO ENHANCE THE CONVECTIVE ACTIVITY ASSOCIATED WITH THE ABOVE MENTIONED SURFACE LOW...AND IS ALSO HELPING TO INDUCE SOME SHOWER ACTIVITY OVER THE ABC ISLANDS. CURACAO REPORTED THIS MORNING A TOTAL AMOUNT OF 2.06 INCHES OF RAIN FOR THE PAST 24 HOURS. PATCHES OF LOW LEVEL MOISTURE WITH EMBEDDED LIGHT SHOWERS ARE AFFECTING THE GREATER ANTILLES UNDER A E-NE FLOW. SIMILAR CLOUDINESS IS NOTED OVER HONDURAS WITH MAINLY LIGHT RAIN. ATLANTIC OCEAN... A DEEP LAYERED TROUGH OVER THE E CONUS CONTINUES TO APPROACH THE EASTERN SEABOARD...WITH STRONG WESTERLY FLOW ALOFT OVER THE W ATLC. THIS UPPER FEATURE SUPPORTS A COLD FRONT THAT LIES ACROSS THE SE CONUS AND THE GULF OF MEXICO. A REINFORCING COOLER AND DRIER AIRMASS FOLLOWS THE FRONT. A PRE-FRONTAL TROUGH IS WITHIN 180 NM SE OF THE FRONT AND ENTERS THE FORECAST AREA NEAR 31N77W THEN CONTINUES SW TO THE NW BAHAMAS. ISOLATED SHOWERS ARE ASSOCIATED WITH THIS TROUGH. FARTHER E...A SHARP UPPER TROUGH IS OVER THE CENTRAL ATLC WITH A 100 KT CYCLONICALLY-CURVED UPPER LEVEL JET ROUNDING THE BASE OF THIS TROUGH. THIS TROUGH SUPPORTS A DEEPENING SFC LOW LOCATED NEAR 31N50W. A COLD FRONT EXTENDS FROM THIS LOW ALONG 26N48W 20N51W. TIGHT PRES GRADIENT BETWEEN THIS SFC LOW AND HIGH PRES OVER THE W ATLC IS RESULTING IN A BELT OF STORM WIND FORCE WITHIN 240 NM WEST SEMICIRCLE OF LOW CENTER. SCATTERED MODERATE CONVECTION IS FOUND WITHIN 200 NM AHEAD OF THE FRONT N OF 26N. A DIFFLUENT PATTERN ALOFT...AHEAD OF THE AFOREMENTIONED UPPER-LEVEL TROUGH...IS ENHANCED THIS SHOWER ACTIVITY. FARTHER TO THE SOUTH...A SURFACE TROUGH RUNS 20N48W TO 10N51W. AN EARLIER QSCAT PASS SHOWED THE WIND SHIFT RELATED TO THIS TROUGH. A 1011 MB REMAINS NEAR 27N31W GENERATING SOME SHOWER ACTIVITY PARTICULARLY EAST OF THE CENTER DUE TO THE PRESENCE OF UPPER DIFFLUENCE ASSOCIATED WITH ANOTHER UPPER-LEVEL TROUGH THAT ENTERS THE AREA NEAR 31N32W. THIS LOW IS FORECAST TO DISSIPATE IN ABOUT 24 HOURS. THE REMAINDER OF THE E ATLC IS UNDER THE INFLUENCE OF A SFC RIDGE ANCHORED N OF THE AZORES. A JET STREAM BRANCH WITH CORE WINDS OF 70-90 KT CROSSES JUST N OF THE CAPE VERDE ISLANDS THEN CONTINUES E-NE OVER WEST AFRICA WITH MAXIMUM WINDS OF 110-130 KT. $$ GR