000 AXNT20 KNHC 051054 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST TUE MAR 05 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 1015 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 08N13W TO 06N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N18W TO 01N29W TO THE EQUATOR NEAR 38W. SCATTERED MODERATE CONVECTION IS FROM 01N-06N BETWEEN 06W-11W...AND S OF 04N BETWEEN 25W-36W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL TROUGH IS OVER THE BASIN WITH A WEAK TROUGH AXIS EXTENDING FROM THE NE GULF NEAR 29N86W SW TO A BASE OVER CENTRAL MEXICO NEAR 19N100W. MOSTLY DRY AIR AND OVERALL SUBSIDENCE IS NOTED ALOFT WHICH FURTHER SUPPORTS A SURFACE RIDGE ANCHORED BY A 1023 MB HIGH CENTERED OVER THE CENTRAL FLORIDA PENINSULA NEAR 29N80W. SOUTHERLY RETURN FLOW DOMINATES ON THE WESTERN PERIPHERY OF THE RIDGE WITH THE STRONGEST WINDS...IN THE RANGE OF 20 TO 25 KT LOCATED NW OF A LINE FROM 30N85W TO 21N97W. THE RETURN FLOW IS EXPECTED TO PERSIST THROUGH TUESDAY UNTIL THE NEXT COLD FRONT EMERGES OFF THE TEXAS AND LOUISIANA COAST BY LATE AFTERNOON TUESDAY. THEREAFTER...ANOTHER ROUND OF NORTHERLY WINDS WILL FOLLOW IN WAKE OF THE COLD FRONT AS THE DEVELOPING LOW PRESSURE AREA SKIRTS ACROSS THE SE CONUS AND TENNESSEE RIVER VALLEY TO THE MID-ATLC COAST. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER VENEZUELA NEAR 08N64W WHICH IS PROVIDING THE ENTIRE CARIBBEAN BASIN WITH SOUTHWEST TO WESTERLY FLOW ALOFT. WHILE UPPER LEVEL MOISTURE CONTINUES TO STREAM NORTHEASTWARD FROM THE EAST PACIFIC AND NORTHERN SOUTH AMERICAN CONTINENT...LOW-LEVEL MOISTURE IS FOCUSED MAINLY WEST OF A FRONTAL BOUNDARY ANALYZED AS A COLD FRONT FROM 20N63W IN THE ATLC OCEAN TO 17N66W SOUTH OF PUERTO RICO...THEN MEANDERS SW AS A DISSIPATING STATIONARY FRONT ALONG 17N66W TO 15N74W TO 13N77W. LOW-TOPPED ISOLATED SHOWERS ARE NOTED ON SATELLITE IMAGERY N OF 16N W OF 80W... AND S OF 16N BETWEEN 70W-85W...INCLUDING PORTIONS OF INLAND NICARAGUA AND COSTA RICA. LOOKING AHEAD...THE FRONTAL BOUNDARY WILL CONTINUE TO BECOME MORE DIFFUSE THROUGH LATE TUESDAY WITH THE USUAL E-NE TRADE WINDS EXPECTED TO RE-ESTABLISH THEMSELVES BY WEDNESDAY AS A RIDGE SETTLES IN OVER THE SW NORTH ATLC TO THE NORTH. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL LOW IS CENTERED OFFSHORE OF THE NEW ENGLAND COAST NEAR 43N66W THAT SUPPORTS A COLD FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 32N41W. THE FRONT EXTENDS SW ALONG 30N46W TO 25N54W TO THE US/UK VIRGIN ISLANDS NEAR 18N65W AND INTO THE CENTRAL CARIBBEAN SEA. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 180 NM EAST OF THE FRONT NORTH OF 24N AND WITHIN 180 NM WEST OF THE FRONT AND S OF 21N BETWEEN 64W-73W. AN UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR IMAGERY IN THE VICINITY OF 33N58W THAT SUPPORTS A SECONDARY SURGE OF COLD AIR ACROSS THE SW NORTH ATLC ANALYZED AT THE SURFACE AS A COLD FRONT FROM 32N59W SW TO 27N66W. NW WINDS OF GALE FORCE WERE NOTED ON A RECENT ASCAT PASS AROUND 05/0128 UTC. OTHERWISE...THE REMAINDER OF THE SW NORTH ATLC W OF 68W IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1023 MB HIGH CENTERED OVER THE CENTRAL FLORIDA PENINSULA NEAR 29N80W. FARTHER EAST OVER THE CENTRAL ATLC AND PORTIONS OF THE EASTERN ATLC...ANOTHER BROAD SURFACE RIDGE DOMINATES AS A 1016 MB HIGH IS CENTERED NEAR 22N43W. THE ONLY EXCEPTION TO THE RIDGE ARE NW WINDS OVER THE FAR NE ATLC GENERATING POSSIBLE GALE FORCE CONDITIONS GENERALLY N OF 29N E OF 23W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN