000 AXNT20 KNHC 121140 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST THU DEC 12 2013 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE EAST TROPICAL ATLC NEAR 05N09W TO 04N16W. THE ITCZ AXIS EXTENDS FROM 04N16W TO 04N34W TO 06N50W. SCATTERED MODERATE CONVECTION AND TSTMS ARE FROM 02N-07N BETWEEN E OF 20W. SCATTERED MODERATE CONVECTION IS WITHIN AN AREA ENCLOSED BY A LINE FROM 18N16W TO 06N28W AND A LINE EXTENDING FROM 20N23W TO 08N43W. ...DISCUSSION... GULF OF MEXICO... A BROAD MIDDLE-LEVEL TROUGH WITH AXIS EXTENDING FROM THE NE U.S.A TO THE CENTRAL GULF SUPPORTS A STATIONARY FRONT ANALYZED FROM WESTERN-SOUTHERN FLORIDA NEAR 26N81W SW TO 23N90W TO THE BAY OF CAMPECHE NEAR 18N94W. A 1040 MB HIGH CENTERED IN THE MIDDLE MISSISSIPPI VALLEY NEAR 38N91W EXTENDS A RIDGE AXIS INTO THE GULF AND PROVIDES NORTHEASTERLY WIND FLOW UP TO 25 KT ACROSS THE ENTIRE BASIN. EXCEPT FOR THE SW BASIN S OF 24N AND THE SE GULF S OF 25N...SSMI TPW IMAGERY DEPICT DRY AIR ACROSS THE BASIN AT THE LOWER LEVELS WHICH IS SUSTAINING FAIR WEATHER. ON THE SW GULF...DRY AIR SUBSIDENCE FROM A MIDDLE-LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 20N94W SUPPORTS FAIR WEATHER. ON THE SE GULF...A SURFACE TROUGH OVER THE FAR NW CARIBBEAN SEA ADVECTS VERY MOIST AIR TO THE REGION TO SUPPORT SCATTERED SHOWERS OVER THE FLORIDA STRAITS AND THE YUCATAN CHANNEL. HIGH PRESSURE AND NORTHEASTERLY WIND FLOW ARE EXPECTED TO CONTINUE ACROSS THE GULF THROUGHOUT FRI MORNING. THE FRONTAL BOUNDARY IS FORECAST TO MOVE OUT OF THE GULF WATERS BY EARLY FRI. A COLD FRONT IS FORECAST TO EMERGE ACROSS THE NW GULF SAT AFTERNOON. CARIBBEAN SEA... LOW-LEVEL MOISTURE CONVERGENCE IS ALONG THE COASTLINE FROM THE YUCATAN PENINSULA TO CENTRAL PANAMA TO SUPPORT SCATTERED MODERATE CONVECTION WITHIN 170 NM FROM THE COAST OF NICARAGUA TO CENTRAL PANAMA. SIMILAR CONVECTION IS S OF 22N W OF 82W ASSOCIATED WITH THE REMNANTS OF A SURFACE TROUGH THAT AT 0900 UTC EXTENDS FROM 22N86W TO S OF BELIZE NEAR 15N88W. OVER THE CENTRAL BASIN...AT THE LOWER LEVELS AN INVERTED TROUGH SUPPORTS A SURFACE TROUGH FROM 24N71W ON THE ATLC TO CENTRAL HISPANIOLA NEAR 19N71W TO 16N71W. THE SURFACE TROUGH IS GENERATING ISOLATED SHOWERS AND TSTMS OVER SOUTHERN ADJACENT WATERS N OF 15N BETWEEN 67W-73W. ALOFT AND ACROSS THE REMAINDER BASIN WESTERLY WIND FLOW AND DRY AIR SUBSIDENCE DOMINATE AND SUPPORT FAIR WEATHER. OTHERWISE...A RELATIVELY TIGHT PRESSURE GRADIENT OVER THE CENTRAL-EASTERN BASIN SUPPORTS 20-25 KT WINDS EXPECTED TO PERSIST THROUGHOUT SAT MORNING. RAINSHOWERS ASSOCIATED WITH THE REMNANTS OF THE SURFACE TROUGH ARE EXPECTED THROUGHOUT THU NIGHT. HISPANIOLA... AN INVERTED TROUGH AT THE LOWER LEVELS SUPPORTS A SURFACE TROUGH FROM 24N71W ON THE ATLC TO CENTRAL HISPANIOLA NEAR 19N71W TO 16N71W. THE SURFACE TROUGH IS GENERATING ISOLATED SHOWERS AND TSTMS OVER SOUTHERN ADJACENT WATERS N OF 15N BETWEEN 67W-73W. SHOWERS ASSOCIATED WITH THIS TROUGH WILL CONTINUE THROUGHOUT THU NIGHT. ATLANTIC OCEAN... A BROAD MIDDLE-LEVEL TROUGH WITH AXIS EXTENDING FROM THE NE U.S.A CONUS TO THE CENTRAL GULF SUPPORTS A STATIONARY FRONT ANALYZED FROM 30N70W SW TO THE EASTERN-CENTRAL FLORIDA COAST NEAR 26N80W. VERY DRY AIR ACROSS THE SW NORTH ATLC AND CENTRAL ATLC HINDERS CONVECTION AT THE TIME. FARTHER EAST OVER THE CENTRAL ATLC...A 1026 MB HIGH IS NEAR 28N49W WHICH IS EXPECTED TO DRIFT E OVER THE NEXT 24 HOURS MAINTAINING FAIR WEATHER CONDITIONS. A WEAK SURFACE TROUGH IS SW OF THE RIDGE EXTENDING FROM 23N60W TO 19N64W WITH NO CONVECTION ASSOCIATED WITH IT AT THE TIME. A MIDDLE TO UPPER LEVEL NARROW TROUGH ALONG THE EASTERN ATLC SUPPORTS A FRONTAL SYSTEM ANALYZED AS A DISSIPATING COLD FRONT FROM 30N14W TO 25N16W TO 20N21W. SCATTERED SHOWERS AND TSTMS ASSOCIATED WITH THIS FRONTAL SYSTEM ARE N OF 23N BETWEEN 13W-19W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR