000 AXNT20 KNHC 141144 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST FRI DEC 14 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 INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM THE AFRICAN COAST NEAR 08N13W TO 02N29W TO 03N45W TO 02N50W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 03N-07N BETWEEN 09W-13W. WIDELY SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 07N BETWEEN 18W-41W. ...DISCUSSION... GULF OF MEXICO... MOSTLY WEST-NORTHWESTERLY UPPER LEVEL FLOW IS OVER THE GULF BASIN THIS MORNING WITH WATER VAPOR IMAGERY INDICATING RELATIVELY DRY AND STABLE CONDITIONS E OF 90W. WITH THE SOUTHWESTERN EXTENT OF AN UPPER LEVEL TROUGH PROGRESSING EASTWARD OVER THE FLORIDA PENINSULA AND INTO THE SW NORTH ATLC REGION...A DISSIPATING STATIONARY FRONT EXTENDS FROM THE FLORIDA STRAITS TO THE NORTHWESTERN CUBA COAST NEAR 23N84W TO 21N87W IN THE YUCATAN CHANNEL. ISOLATED SHOWERS REMAIN LIMITED TO THE FLORIDA STRAITS AND AREAS S OF 24N E OF 82W. OTHERWISE...THE REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1028 MB HIGH CENTERED OVER SE TENNESSEE NEAR 35N86W. THE RIDGE AXIS EXTENDS SW THROUGH 30N90W TO THE MEXICO COAST NEAR 20N97W. MOSTLY NE TO E WINDS PREVAIL E OF 92W...WITH E-SE WINDS ESTABLISHING THEMSELVES W OF 92W WITH WEAK LOW-LEVEL MOISTURE CONVERGENCE AND POSSIBLE ISOLATED SHOWERS OCCURRING W OF 96W. THE RETURN FLOW IS FORECAST TO CONTINUE SPREADING EASTWARD THROUGH THE WEEKEND AS THE HIGH OVER THE SE CONUS SLIDES EAST INTO THE SW NORTH ATLC. CARIBBEAN SEA... UPPER LEVEL NORTHWESTERLY FLOW DOMINATES OVER THE CARIBBEAN BASIN THIS MORNING BETWEEN AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED IN THE EAST PACIFIC REGION NEAR 13N93W AND AN UPPER LEVEL LOW CENTERED OVER THE CENTRAL ATLC NEAR 20N50W. WATER VAPOR IMAGERY INDICATES THAT VERY DRY AIR AND SUBSIDENCE PREVAILS IN THE MIDDLE AND UPPER LEVELS OF THE ATMOSPHERE. AT THE SURFACE...THE PRESSURE GRADIENT HAS CONTINUED TO RELAX OVER THE LAST 24 TO 36 HOURS WITH E-NE TRADES DECREASING IN MAGNITUDE AND NOW RANGE GENERALLY FROM 10 TO 20 KT. WHILE NO SIGNIFICANT CONVECTION IS OCCURRING...A FEW ISOLATED SHOWERS AND TSTMS ARE NOTED ON SATELLITE IMAGERY S OF 11N IN THE SW CARIBBEAN DUE TO CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS ANALYZED ALONG 07N/08N FROM NORTHERN COLOMBIA WESTWARD TO SOUTHERN COSTA RICA. ELSEWHERE...THE GREATEST CONCENTRATION OF LOW-LEVEL MOISTURE IS FOUND OVER THE EASTERN CARIBBEAN WITH WIDELY SCATTERED LOW-TOPPED SHOWERS OCCURRING WITHIN 120 NM EITHER SIDE OF A LINE FROM 12N61W TO 16N69W...AND FROM 16N-21N BETWEEN 65W-72W... INCLUDING PUERTO RICO AND THE MONA PASSAGE. OTHER ISOLATED SHOWERS ARE S OF 15N BETWEEN 76W-85W. THIS OVERALL SYNOPTIC PATTERN OF FAIRLY TRANQUIL WEATHER IS EXPECTED THROUGH THE WEEKEND. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS OVER THE SW NORTH ATLC WITH AXIS EXTENDING FROM 36N62W TO A BASE OVER THE SOUTHERN FLORIDA PENINSULA NEAR 26N82W. THIS TROUGHING SUPPORTS A COLD FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 32N66W THAT EXTENDS SW TO THE NW BAHAMAS NEAR 25N78W AND INTO THE FLORIDA STRAITS AS A DISSIPATING STATIONARY FRONT TO BEYOND 24N82W. LOW-LEVEL MOISTURE CONVERGENCE NEAR THE FRONT IS GENERATING ISOLATED SHOWERS WITHIN 120 NM EITHER SIDE OF THE FRONT...AND N OF 26N BETWEEN 58W AND THE FRONT IN AN AREA OF WEAK PRE-FRONTAL TROUGHING. FARTHER EAST...A MIDDLE TO UPPER LEVEL LOW IS CENTERED NEAR 20N50W THAT SUPPORTS A 1008 MB LOW NEAR 19N50W WITH A SURFACE TROUGH AXIS EXTENDING NORTH FROM THE LOW TO 26N48W AND SOUTH-SOUTHWEST TO 16N50W THEN TO 07N56W. SATELLITE IMAGERY PRESENTS THIS SYSTEM WITH A CLASSIC COMMA CLOUD SIGNATURE AS MIDDLE TO UPPER LEVEL MOISTURE CONTINUES TO WRAP INTO THE LOW CENTER. WATER VAPOR IMAGERY ALSO INDICATES DRIER AIR WRAPPING INTO THE LOW CENTER FROM THE WEST AND NORTHWEST. GIVEN INCREASED INSTABILITY AND MAXIMIZED UPPER LEVEL DIFFLUENCE EAST OF THE LOW...WIDELY SCATTERED SHOWERS AND TSTMS ARE OCCURRING FROM 17N-25N BETWEEN 45W-52W...AND SCATTERED SHOWERS AND TSTMS OVER A LARGER AREA FROM 09N-25N BETWEEN 32W-48W. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1023 MB HIGH CENTERED NEAR 29N31W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN