000 AXNT20 KNHC 211754 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST MON DEC 21 2009 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 1715 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 9N13W 4N30W 3N52W. SCATTERED MODERATE CONVECTION IS FROM 3N-6N BETWEEN 25W-33W. SIMILAR CONVECTION IS FROM 1N-5N BETWEEN 44W-52W. ...DISCUSSION... GULF OF MEXICO... A SURFACE RIDGE CONTINUES ITS CONTROL OVER THE GULF OF MEXICO ANCHORED BY A TRIO OF HIGH CENTERS STRETCHING FROM A 1027 MB HIGH OVER SOUTHERN ALABAMA TO A 1026 MB HIGH CENTERED OVER THE NW GULF WATERS NEAR 29N93W THEN TO A 1026 MB HIGH OVER THE EAST CENTRAL MEXICO COAST NEAR TAMPICO. MAINLY LIGHT NE TO E WINDS ARE OBSERVED ACROSS THE BASIN. ALOFT...MOIST SWLY FLOW COVERS A MAJORITY OF THE GULF EAST OF AN UPPER LEVEL TROUGH AXIS EXTENDING FROM SOUTHERN LOUISIANA CLIPPING THE NW GULF WATERS TO SOUTHERN MEXICO NEAR THE ISTHMUS OF TEHUANTEPEC. ABUNDANT MIDDLE TO UPPER LEVEL TROPICAL MOISTURE IS ADVECTING NE ACROSS THE YUCATAN PENINSULA...EASTERN GULF...AND FLORIDA PENINSULA. THE UPPER LEVEL TROUGH AND DIFFLUENT ENVIRONMENT EAST OF THE AXIS IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS S OF 23N W OF 90W ALONG WITH POSSIBLE ISOLATED SHOWERS ACROSS THE YUCATAN PENINSULA AND YUCATAN CHANNEL AS THE UPPER LEVEL TROUGH SLOWLY MOVES EASTWARD. AS THE SURFACE RIDGE MOVES EASTWARD ACROSS THE NE GULF COAST...SE TO S RETURN FLOW IS FORECAST TO BEGIN LATE MONDAY WITH THE NEXT COLD FRONT EXPECTED TO ENTER THE NW GULF WATERS EARLY THURSDAY. CARIBBEAN SEA... A STATIONARY FRONT EXTENDS ACROSS THE WESTERN CARIBBEAN FROM HISPANIOLA TO SOUTHERN JAMAICA ALONG 16N80W TO 9N83W. A SURFACE TROUGH IS EAST OF THE FRONT EXTENDING FROM 18N73W TO 14N76W TO 10N76W. N-NE WINDS UP TO 30 KTS WERE CAPTURED ON AN EARLIER WINDSAT SCATTEROMETER PASS AT 21/1122 UTC NORTH OF THE FRONT TO 20N BETWEEN 79W-84W. THE FRONT LIES BENEATH MOIST SWLY FLOW ALOFT ON THE WESTERN SIDE OF A LARGE AND BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED EAST OF THE LESSER ANTILLES NEAR 16N59W. THE RIDGE IS DRAWING TROPICAL MOISTURE ACROSS CENTRAL AMERICA AND THE CARIBBEAN W OF 75W. THIS ALONG WITH SURFACE CONVERGENCE NEAR THE FRONT AND SURFACE TROUGH IS SUPPORTING SCATTERED SHOWERS W OF 78W S OF THE STATIONARY FRONT AND ELSEWHERE ACROSS THE REMAINDER OF THE NW CARIBBEAN NW OF THE FRONT...AS WELL AS OVER PORTIONS OF NORTHERN HISPANIOLA. DRY AIR AND SUBSIDENCE COVER THE FAR EASTERN CARIBBEAN E OF 68W AS NOTED IN WATER VAPOR IMAGERY RESULTING IN A STABLE ENVIRONMENT AND CLEAR SKIES THIS AFTERNOON. ATLANTIC OCEAN... AN OCCLUDED 970 MB LOW IS LOCATED SE OF NOVA SCOTIA CANADA NEAR 42N58W WITH A COLD FRONT ENTERING THE DISCUSSION AREA NEAR 32N45W CONTINUING SW ALONG 26N55W TO 22N64W AND BECOMES STATIONARY TO HISPANIOLA AND INTO THE WESTERN CARIBBEAN. ISOLATED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE FRONT...AND FARTHER E N OF 25N BETWEEN 37W-49W. A SECONDARY COLD FRONT FOLLOWS TO THE NW ALONG 31N57W TO 27N71W...WITH STRATO- CUMULUS CLOUDS AND STRONG W-NW WINDS OCCURRING BEHIND THE FRONT. FARTHER EAST...A COLD FRONT ENTERS THE FAR NE CORNER OF THE DISCUSSION AREA NEAR 32N11W AND EXTENDS S-SW THROUGH THE CANARY ISLANDS TO 21N25W. SCATTERED SHOWERS ARE N OF 20N E OF 22W. THE FRONT IS SUPPORTED ALOFT BY AN UPPER LEVEL TROUGH AXIS THAT EXTENDS FROM 32N22W TO THE CAPE VERDE ISLANDS TO 6N37W IN THE TROPICAL ATLC. ELSEWHERE A SURFACE RIDGE AXIS EXTENDS E-W ALONG 17N/18N BETWEEN THE W AFRICA COAST THROUGH A 1017 MB HIGH CENTERED NEAR 18N44W TO OVER THE EASTERN CARIBBEAN SEA NEAR PUERTO RICO. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE. $$ HUFFMAN