000 AXNT20 KNHC 131142 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST THU DEC 13 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 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 1115 UTC ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 8N13W 6N21W 4N30W 3N40W EQUATOR49W. SCATTERED MODERATE CONVECTION IS FROM 4N-6N E OF 14W...FROM 1N-4N BETWEEN 24W-29W...FROM 5N-8N BETWEEN 33W-38W AND AIDED BY A WLY UPPER JET FROM 8N-11N BETWEEN 41W-60W. DISCUSSION... GULF OF MEXICO... A SLOW MOVING COLD FRONT HAS WORKED ITS WAY INTO THE FAR NW CORNER OF THE REGION EXTENDING FROM SW LOUISIANA TO NRN MEXICO NEAR 24N98W AND THEN STATIONARY ALONG THE E SLOPES OF THE SIERRA MADRE. CONSIDERABLY COOLER AND DRIER AIR IS FILTERING IN BEHIND THE FRONT. DOPPLER RADAR SHOWS A NARROW LINE OF SCATTERED SHOWERS WITHIN 30 NM AHEAD OF THE BOUNDARY. ELSEWHERE ...MODERATE SFC RIDGING CONTINUES TO DOMINATE EXTENDING W FROM THE WRN ATLC. LOW-LEVEL ELY FLOW IS ADVECTING ISOLATED TO SCATTERED SHOWERS FROM THE ATLC INTO THE FLA STRAITS. IN THE MID AND UPPER LEVELS...A RIDGE HAS BEEN SLOW TO MOVE OVERHEAD ALLOWING THE FLOW ALOFT TO BE LIGHT AND ATMOSPHERE VERY STABLE. A SHORTWAVE IS OVER THE CENTRAL U.S. PROVIDING SUPPORT FOR THE COLD FRONT MENTIONED. THIS TROUGH...HOWEVER...IS EXPECTED TO FLATTEN OUT LATER TODAY LIMITING THE PROGRESS OF THE COLD FRONT. THE NEXT TROUGH/FRONT IS ANTICIPATED TO BE MUCH STRONGER ENTERING THE NW WATERS EARLY SAT. CARIBBEAN SEA... THE LAST ADVISORY WAS ISSUED ON T.D. OLGA YESTERDAY EVENING. THE REMNANT LOW IS CURRENTLY CENTERED IN THE NW CARIB NEAR 19N79W MOVING W 10-15 KT. THE LOW-LEVEL CIRCULATION IS STILL EASILY IDENTIFIABLE ON NIGHT CHANNEL VIS IMAGES BUT CONVECTION IS CONFINED TO A FEW SMALL BANDS N OF THE CENTER AND SLIGHTLY LARGER OUTER BANDS FARTHER N OVER AND JUST N OF CUBA AND PORTIONS OF THE BAHAMAS...AS NOTED IN CUBAN DOPPLER RADAR IMAGES AND LIGHTNING DATA. FAIRLY DENSE LOW TO MID LEVEL CLOUDS AND SHALLOWER SHOWER/TSTM ACTIVITY IS ELSEWHERE N AND E OF THE CENTER N OF 17N BETWEEN 73W-80W. ONLY ISOLATED SHOWERS ARE ON THE W SIDE OF THE LOW N OF 16N BETWEEN 79W-83W. SIMILAR ISOLATED ACTIVITY IS E OF 73W ENHANCED BY AN INCREASE IN THE ELY TRADE WIND FLOW. ATLANTIC OCEAN... BANDS OF SHOWERS/TSTMS...ASSOCIATED WITH THE REMNANTS OF T.D. OLGA...IS AFFECTING PORTIONS OF THE SW ATLC INCLUDING THE BAHAMAS S OF 25N BETWEEN 72W-79W. LIGHTNING DATA DEPICTS THE STRONGEST BANDS OVER AND JUST N OF THE COAST OF CUBA. SEE CARIB SECTION FOR MORE DETAILS. THE REMAINDER OF THE DISCUSSION AREA IS DOMINATED BY MODERATE TO STRONG SFC RIDGING SUPPORTED BY A 1023 MB HIGH OFF THE GEORGIA COAST NEAR 31N79W...1026 MB HIGH LOCATED SE OF BERMUDA NEAR 28N60W AND A 1024 MB NEAR 34N38W AND STRONGER HIGH PRES OVER N AFRICA AND SW EUROPE. THERE IS A SLIGHT WEAKNESS IN THE RIDGE E OF ABOUT 40W DUE TO A DISSIPATING COLD FRONT THAT EXTENDS TO 27N38W AND A LARGE INVERTED TROUGH NEAR THE AFRICAN COAST N OF 22N. A 1014 MB LOW HAS DEVELOPED ALONG THE TROUGH AXIS S OF THE CANARY ISLANDS NEAR 26N17W AS NOTED IN EARLIER ASCAT PASS. THE MID AND UPPER PATTERN CONSISTS OF A LONGWAVE RIDGE/TROUGH N OF 16N WITH A SERIES OF EMBEDDED SHORTWAVES E OF ABOUT 50W. THE ONLY AREA OF ORGANIZED CLOUDINESS IN THE SUBTROPICS...BESIDES FOR THE REMNANTS OF OLGA...IS IN THE FAR E PORTION N OF 23N E OF 16W ASSOCIATED WITH DIFFLUENCE ALOFT TO THE SE OF AN UPPER LOW NEAR 30N21W AIDED BY AN ASSOCIATED SFC TROUGH NEAR THE AFRICAN COAST. IN THE DEEP TROPICS...THE FLOW ALOFT IS FAIRLY ZONAL AND QUITE STRONG. THIS STRONG FLOW AND A SLIGHTLY DIFFLUENT PATTERN IS ENHANCING SCATTERED MODERATE TO STRONG CONVECTION FROM 5N-11N BETWEEN 33W-60W. DEBRIS MOISTURE HAS SPREAD WELL E TO AFRICA MAINLY S OF 18N. $$ CANGIALOSI