000 AXNT20 KNHC 112355 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST FRI JAN 11 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 06N11W TO 06N12W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N12W TO 06N30W TO THE EQUATOR NEAR 48W. NO SIGNIFICANT CONVECTION NOTED ON SATELLITE IMAGERY. ...DISCUSSION... GULF OF MEXICO... WHILE AN UPPER LEVEL TROUGH WITH AXIS FROM OVER THE FLORIDA PANHANDLE NEAR 30N85W S-SW TO 15N93W CONTINUES TO PROGRESS EASTWARD...THE MORE IMPACTING FEATURE OVER THE GULF THIS EVENING IS A MIDDLE LEVEL RIDGE ANCHORED OVER THE FLORIDA STRAITS AND BAHAMAS NEAR 24N80W. THE RIDGING EXTENDS NORTHWARD OVER THE EASTERN SEABOARD OF THE U.S. AND INFLUENCE IS NOTED ON WATER VAPOR IMAGERY BETWEEN 60W-98W. THE MID-LEVEL RIDGE SUPPORTS AN AREA OF SURFACE HIGH PRESSURE OVER MUCH OF THE GULF E OF 90W THAT EXPANDS EASTWARD INTO THE SW NORTH ATLC REGION. ACROSS THE WESTERN GULF...A DISSIPATING STATIONARY FRONT IS ANALYZED FROM 29N91W TO 26N95W TO 21N96W WITH ISOLATED SHOWERS AND TSTMS OCCURRING N OF 28N BETWEEN 90W-92W...INCLUDING INLAND PORTIONS OF SOUTHEASTERN LOUISIANA. MIDDLE TO UPPER LEVEL MOISTURE AND CLOUDINESS INCREASES OVER THE NORTHWESTERN PORTIONS OF THE GULF AS A LONGWAVE TROUGH REMAINS OVER MUCH OF THE WESTERN CONUS. BY SUNDAY...MID-LEVEL SHORTWAVE ENERGY ROUNDING THE BASE OF THE BROADER TROUGH WILL INTRODUCE THE NEXT COLD FRONT TO THE GULF BASIN BY SUNDAY MORNING WITH WINDS SHIFTING NORTHERLY OVER THE NW GULF AND AREAS W OF 95W BY SUNDAY EVENING. CARIBBEAN SEA... A MIDDLE TO UPPER LEVEL RIDGE AND MOSTLY DRY AIR IN SUBSIDENCE IMPACTS MUCH OF THE CARIBBEAN THIS EVENING AS FAIRLY TRANQUIL CONDITIONS PREVAIL CONVECTIVELY SPEAKING. WHILE A STRONG SURFACE RIDGE IS LOCATED TO THE NORTH ANCHORED IN THE WESTERN NORTH ATLC AND LOWER PRESSURE IS LOCATED OVER NORTHWESTERN SOUTH AMERICA... THE EXISTING TIGHTENED PRESSURE GRADIENT CONTINUES TO CREATE STRONG TRADE WINDS IN THE RANGE OF 20 TO 30 KT ACROSS THE BASIN BETWEEN 64W-81W. THE GRADIENT IS EXPECTED TO RELAX SOMEWHAT BY EARLY SUNDAY AS WEAKER HIGH PRESSURE SETTLES IN OVER THE SW NORTH ATLC NEXT WEEK. OTHERWISE...LOW-TOPPED ISOLATED SHOWERS ARE EXPECTED TO CONTINUE ACROSS THE BASIN THROUGH THE OVERNIGHT HOURS E OF 70W INCLUDING PUERTO RICO AND THE LESSER ANTILLES... AND FROM 14N-17N BETWEEN 70W-81W. ATLANTIC OCEAN... MUCH OF THE SW NORTH ATLC IS UNDER THE INFLUENCE OF A MIDDLE TO UPPER LEVEL RIDGE WITH AXIS ALONG 76W THAT SUPPORTS SURFACE HIGH PRESSURE W OF 60W. MOSTLY FAIR CONDITIONS ARE NOTED OVER THIS AREA WITH ONLY A FEW ISOLATED TSTMS S OF 23N BETWEEN 60W-75W. OVER THE CENTRAL ATLC...A DEEP LAYERED LOW IS CENTERED NORTH OF THE DISCUSSION AREA NEAR 41N50W THAT SUPPORTS A COLD FRONT ANALYZED INTO THE AREA NEAR 32N43W EXTENDING SW TO 26N50W TO 25N60W. WITH MOST OF THE STRONGER UPPER LEVEL DYNAMICS WELL TO THE NORTH OF 30N...WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 90 NM EAST OF THE COLD FRONT N OF 30N. A PRE-FRONTAL SURFACE TROUGH IS ALSO ANALYZED FROM 27N46W TO 20N52W WITH ONLY A FEW ISOLATED SHOWERS OCCURRING WITHIN 75 NM EITHER SIDE OF THE BOUNDARY. OTHERWISE...THE REMAINDER OF THE EASTERN ATLC IS UNDER QUIET CONDITIONS THIS EVENING AS SURFACE RIDGING DOMINATES E OF 30W ANCHORED BY A 1025 MB HIGH CENTERED NEAR 36N16W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN