000 AXNT20 KNHC 210551 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST MON FEB 21 2011 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ... ITCZ AXIS IS ANALYZED ALONG 06N11W TO 03N33W INTO NE BRAZIL NEAR THE EQUATOR AND 49W. ISOLATED MODERATE CONVECTION IS FROM THE EQUATOR TO 03N BETWEEN 17W-25W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE RESIDES ALOFT OVER THE ENTIRE GULF WITH AXIS ALONG 90W. MOSTLY DRY AIR AND STRONG SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY WHICH IS ANTICIPATED TO CONTINUE PROVIDING MOSTLY CLEAR SKIES THROUGH THE OVERNIGHT HOURS INTO MONDAY. AT THE SURFACE...A 1023 MB HIGH IS CENTERED OFF THE COAST OF THE CAROLINAS NEAR 33N76W THAT EXTENDS A RIDGE AXIS SW ACROSS THE FLORIDA PENINSULA TO THE SOUTHWESTERN GULF. SHIP AND BUOY OBSERVATIONS INDICATE S-SE WINDS IN THE RANGE OF 10 TO 20 KT ARE LOCATED ON THE WESTERN PERIPHERY OF THE RIDGE. THIS WIND REGIME WILL REMAIN FAIRLY STATIC THROUGH LATE MONDAY AS THE RIDGE SETTLES IN OVER THE SW NORTH ATLC WATERS. THE NEXT WEAK FRONTAL BOUNDARY IS FORECAST TO IMPACT THE NW GULF WATERS BY EARLY TUESDAY AND LIFT BACK NORTHWARD OVER THE GULF COASTAL PLAIN LATE TUESDAY INTO WEDNESDAY. CARIBBEAN SEA... WATER VAPOR IMAGERY INDICATES VERY DRY AIR ALOFT OVER THE CARIBBEAN SEA BASIN THIS EVENING WITH WEAK UPPER LEVEL LONGWAVE TROUGHING EXTENDING FROM THE WESTERN ATLC OVER THE GREATER ANTILLES AND NORTHERN LEEWARD ISLANDS. AT THE SURFACE...A 1023 MB HIGH IS CENTERED OVER THE W ATLC NEAR 33N76W THAT CONTINUES TO PRODUCE A STRONG PRESSURE GRADIENT OVER MUCH OF THE CARIBBEAN. STRONG NE WINDS ARE OCCURRING ON THE SOUTHERN PERIPHERY OF THE RIDGE AND ARE EXPECTED TO PERSIST THROUGH LATE TUESDAY AS THE HIGH SETTLES FARTHER SOUTHWARD OVER THE SW NORTH ATLC. ENHANCEMENT OF THESE NE WINDS IS EXPECTED TO FILTER THROUGH THE WINDWARD AND MONA PASSAGES THROUGH LATE MONDAY AS THE RIDGE SHIFTS SLOWLY SE. OTHERWISE...LOW-LEVEL MOISTURE ASSOCIATED WITH A WEAKENING FRONTAL BOUNDARY TO THE NORTH OF PUERTO RICO AND THE LEEWARD ISLANDS IS ADVECTING WIDELY SCATTERED SHOWERS OVER MUCH OF THE NE CARIBBEAN THIS EVENING N OF 15N E OF 70W...INCLUDING PUERTO RICO AND THE US/UK VIRGIN ISLANDS. ATLANTIC OCEAN... UPPER LEVEL RIDGING LOCATED OVER MUCH OF THE EASTERN CONUS CONTINUES TO SUPPORT A 1023 MB HIGH CENTERED OFF THE COAST OF THE CAROLINAS NEAR 33N76W. INFLUENCE OF THE SURFACE RIDGE REMAINS MAINLY W OF 66W PROVIDING MOSTLY CLEAR SKIES AND FAIR CONDITIONS FOR THE OVERNIGHT PERIOD. FARTHER EAST...AN UPPER LEVEL TROUGH IS ALONG 60W AND DIPS SOUTHWARD INTO PORTIONS OF THE NE CARIBBEAN SEA. THE UPPER LEVEL TROUGHING SUPPORTS A PAIR OF COLD FRONTS EXTENDING ACROSS THE CENTRAL ATLC. THE EASTERNMOST COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N50W AND EXTENDS SW ALONG 27N55W TO 23N66W. A SECOND REINFORCING FRONT LAGS WEST OF THE MAIN FRONT ANALYZED FROM 32N54W TO 26N64W. PRE-FRONTAL SCATTERED SHOWERS AND TSTMS ARE LOCATED EAST OF THE MAIN FRONT WITHIN 120 NM OF A LINE FROM 22N55W TO 30N48W. ELSEWHERE...ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THE MAIN FRONT AS IT CONTINUES MOVING EASTWARD. SOUTH OF AFOREMENTIONED FRONTAL BOUNDARY...A SURFACE TROUGH IS ANALYZED EAST OF THE LESSER ANTILLES FROM WESTERN SURINAME NEAR 04N57W TO 15N54W. ISOLATED SHOWERS COVER A LARGE AREA WITHIN 300 NM EITHER SIDE OF THE TROUGH...INCLUDING INLAND PORTIONS OF NORTHEASTERN SOUTH AMERICA. ELSEWHERE E OF 42W...A SURFACE RIDGE ANCHORED BY A 1032 MB HIGH CENTERED NORTH OF THE MADEIRA ISLANDS NEAR 35N17W CONTINUES TO PROVIDE MOSTLY FAIR CONDITIONS ACROSS THE EASTERN ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN