000 AXNT20 KNHC 131145 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST THU DEC 13 2012 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 EXTENDS FROM THE AFRICAN COAST NEAR 08N13W TO 04N16W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 04N16W TO 03N32W TO 01N47W. SCATTERED MODERATE CONVECTION IS FROM 01N-06N BETWEEN 11W-40W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR IMAGERY OVER THE SE CONUS WITH AXIS EXTENDING FROM OVER THE CAROLINAS SOUTHWARD TO NEAR 31N79W. THIS TROUGHING SUPPORTS A STATIONARY FRONT ANALYZED FROM THE CENTRAL FLORIDA PENINSULA SW INTO THE GULF FROM 27N82W TO 22N90W TO THE SOUTHERN MEXICO COAST NEAR 19N95W. THE FRONT HAS CONTINUED TO BECOME MORE DIFFUSE OVER THE PAST 24 TO 36 HOURS WITH POSSIBLE ISOLATED SHOWERS OCCURRING WITHIN 90 NM EITHER SIDE OF THE BOUNDARY. TO THE NW OF THE FRONT BETWEEN 85W AND 96W...SKIES CONTINUE TO CLEAR AS THE MIDDLE TO UPPER LEVELS OF THE ATMOSPHERE REMAIN DRY AND STABLE THIS MORNING. A RIDGE CONTINUES BUILDING IN ACROSS THE SE CONUS AND WESTERN GULF WATERS AND IS EXPECTED TO PROVIDE PERSISTENT NORTH- NORTHEASTERLY WINDS E OF 95W THROUGHOUT THE DAY TODAY AS THE FRONT CONTINUES TO DISSIPATE OVER SE PORTIONS OF THE BASIN. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE SW CARIBBEAN NEAR 11N83W AND CONTINUES TO PROVIDE A RELATIVELY STABLE AND TRANQUIL ATMOSPHERE ACROSS MUCH OF THE BASIN THIS MORNING. WEST-NORTHWESTERLY FLOW ALOFT WITHIN DRY AIR AND SUBSIDENCE IS KEEPING SKIES MOSTLY FAIR WITH THE MAIN IMPACT BEING ENHANCED TRADE WINDS GENERALLY E OF 80W. THE PRESSURE GRADIENT IS EXPECTED TO MAINTAIN THESE TRADES THROUGH EARLY FRIDAY AS STRONG RIDGING OVER THE SW NORTH AND CENTRAL ATLC BEGINS TO SLOWLY ERODE AND SHIFT EASTWARD ON THURSDAY. OTHERWISE...A FEW PASSING ISOLATED SHOWERS AND TSTMS ARE NOTED ON SATELLITE IMAGERY FROM 12N-16N BETWEEN 67W-84W...AND ACROSS PORTIONS OF THE NE CARIBBEAN NE OF A LINE FROM 14N61W TO THE MONA PASSAGE NEAR 18N68W...INCLUDING PUERTO RICO...AND THE LEEWARD ISLANDS. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS PROGRESSING EAST- NORTHEASTWARD OVER THE SE CONUS AND SUPPORTS A 1013 MB LOW CENTERED NEAR 34N74W. A STATIONARY FRONT EXTENDS SW FROM THE LOW CENTER TO 30N80W THEN TO THE FLORIDA PENINSULA NEAR 29N81W WITH WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING N OF 28N W OF 69W. THE REMAINDER OF THE SW NORTH ATLC AND CENTRAL ATLC IS UNDER THE INFLUENCE OF A RIDGE ANCHORED BY A 1025 MB HIGH CENTERED NEAR 31N53W. A COUPLE AREAS OF LOW-LEVEL MOISTURE AND EMBEDDED LOW-TOPPED ISOLATED SHOWERS ARE MOVING WESTWARD ON THE SOUTHWESTERN PERIPHERY OF THE RIDGE IMPACTING THE LEEWARD ISLANDS AND AREA S OF 22N BETWEEN 60W-67W...AND AN AREA IN THE VICINITY OF THE TURKS AND CAICOS ISLANDS FROM 19N-25N BETWEEN 68W-73W. OTHERWISE...A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE CENTRAL ATLC NEAR 19N51W THAT CONTINUES TO SUPPORT A SURFACE TROUGH ANALYZED FROM 10N50W TO 20N43W. LOW-LEVEL MOISTURE CONVERGENCE IN THE VICINITY OF THE SURFACE TROUGH ALONG WITH MAXIMIZED MIDDLE TO UPPER LEVEL DIFFLUENCE EAST OF THE UPPER LEVEL LOW IS GENERATING A LARGE AREA OF SCATTERED SHOWERS AND ISOLATED TSTMS FROM 09N-25N BETWEEN 34W-51W. TO THE NORTH OF THIS AREA...SURFACE RIDGING DOMINATES ANCHORED BY A 1025 MB HIGH CENTERED NEAR 30N34W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN