000 AXNT20 KNHC 200545 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT TUE MAR 20 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO 07N21W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N21W TO THE EQUATOR NEAR 36W THEN TO 03S43W. NO SIGNIFICANT CONVECTION NOTED. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE HAS SHIFTED EASTWARD OVER THE PAST 24 HOURS WITH AN AXIS NOW ALONG 85W THIS EVENING. THIS RIDGE LIES EAST OF AN APPROACHING UPPER LEVEL TROUGH CURRENTLY LOCATED OVER THE INTERMOUNTAIN WEST THAT CONTINUES TO ENCROACH ON THE SOUTHERN PLAINS WITH PLENTY OF MIDDLE TO UPPER LEVEL ENERGY ASSOCIATED WITH IT. AT THE SURFACE...THE UPPER LEVEL RIDGING SUPPORTS A 1026 MB HIGH ANCHORED OVER THE SW NORTH ATLC CENTERED NEAR 36N67W THAT EXTENDS A RIDGE AXIS SW TO THE CENTRAL GULF NEAR 27N90W. PRIMARILY FRESH TO STRONG SE WINDS PREVAIL AS NOTED ON RECENT SHIP...BUOY...AND OIL PLATFORM OBSERVATIONS WITH STRONGER WINDS W OF 90W PER A 19/2350 UTC WINDSAT SCATTEROMETER PASS. AS THE UPPER LEVEL TROUGH SLOWLY MOVES EAST OVER THE NEXT 24 TO 36 HOURS...THE ASSOCIATED COLD FRONT WILL CONTINUE TRACKING EAST ACROSS INLAND PORTIONS OF TEXAS AND OKLAHOMA MERGING WITH SECONDARY ENERGY FARTHER WEST AND IS FORECAST TO EMERGE OFF THE TEXAS AND LOUISIANA COAST LATE TUESDAY INTO EARLY WEDNESDAY. SE WINDS ARE FORECAST TO REMAIN BRISK IN THE 20 TO 25 KT RANGE UNTIL FRONTAL PASSAGE WHERE WINDS WILL SHIFT TO N-NW OVER PORTIONS OF THE WESTERN GULF W OF 90W INTO WEDNESDAY. CARIBBEAN SEA... CONFLUENT UPPER LEVEL FLOW IS ACROSS MUCH OF THE WESTERN CARIBBEAN ON THE WESTERN PERIPHERY OF WEAK UPPER LEVEL TROUGHING EXTENDING INTO THE NORTH-CENTRAL CARIBBEAN FROM THE SW NORTH ATLC. THE TROUGH DIPS SOUTHWARD TO A BASE NEAR 17N70W AND WATER VAPOR IMAGERY INDICATES THAT DRY AIR AND SUBSIDENCE COVERS THE BASIN W OF 70W. AS A RESULT...CONDITIONS AT THE SURFACE REMAIN TRANQUIL AND RELATIVELY CLOUD-FREE WITH THE EXCEPTION OF A FEW PASSING HIGH CLOUDS OVER THE NW CARIBBEAN N OF 16N W OF 83W. EAST OF THE TROUGH AXIS AND 70W...SOUTHWESTERLY FLOW ALOFT DOMINATES AND WATER VAPOR IMAGERY SHOWS THAT WHILE THE LOW TO MIDDLE LEVELS OF THE ATMOSPHERE REMAIN DRY AND SUBSIDENT...UPPER LEVEL MOISTURE AND CLOUDINESS CONTINUES TO STREAM NE OVER THE LESSER ANTILLES AND SE CARIBBEAN S OF 16N E OF 70W. THE ENTIRE BASIN IS UNDER THE INFLUENCE OF MODERATE TO FRESH E-NE TRADES WITH HIGHER WINDS TO 25 KT OVER PORTIONS OF THE SOUTHWESTERN AND SOUTH-CENTRAL CARIBBEAN IN THE VICINITY OF THE COLOMBIAN COAST. THIS SYNOPTIC PATTERN ACROSS THE CARIBBEAN IS EXPECTED TO PERSIST THROUGH THE WEEK AS HIGH PRESSURE WILL REMAIN ANCHORED OVER THE SW NORTH ATLC. ATLANTIC OCEAN... WATER VAPOR IMAGERY INDICATES BROAD UPPER LEVEL TROUGHING IS OVER MUCH OF THE SW NORTH ATLC WITH AXIS EXTENDING INTO THE DISCUSSION AREA NEAR 32N50W TO 28N65W TO 20N71W AND INTO THE NORTH-CENTRAL CARIBBEAN SEA. THE NORTHEASTERN PORTION OF THIS TROUGH AXIS SUPPORTS A COLD FRONT ANALYZED TO 32N39W THEN CONTINUING SW AS A SURFACE TROUGH TO 26N52W. WIDELY SCATTERED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE SURFACE TROUGH AND FROM 21N-27N BETWEEN 45W-57W. OTHERWISE...EAST OF THE SURFACE TROUGH...THE SW NORTH ATLC REMAINS UNDER THE INFLUENCE OF A 1026 MB HIGH CENTERED NEAR 36N67W WITH ONLY A FEW ISOLATED SHOWERS OCCURRING WITHIN EASTERLIES FROM 22N-26N BETWEEN 67W-74W. THE REMAINDER OF THE EASTERN ATLC IS INFLUENCED BY A SURFACE RIDGE ANCHORED BY A 1039 MB HIGH CENTERED W OF FRANCE NEAR 47N05W. THE RIDGE AXIS EXTENDS FROM THE HIGH TO 45N13W TO 32N24W TO 27N40W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN