000 AXNT20 KNHC 211141 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...ITCZ... ITCZ AXIS IS ANALYZED ALONG 09N14W TO 02N23W TO THE EQUATOR NEAR 40W AND INTO NE BRAZIL NEAR 02S45W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 01N-04N BETWEEN 18W-21W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE RESIDES ALOFT OVER THE ENTIRE GULF WITH AXIS ALONG 88W. MOSTLY DRY AIR AND STRONG SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY WHICH IS ANTICIPATED TO CONTINUE PROVIDING MOSTLY CLEAR SKIES THROUGHOUT THE DAY ON MONDAY. AT THE SURFACE...A 1022 MB HIGH IS CENTERED IN THE SW NORTH ATLC WATERS NEAR 30N74W 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 W 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 MORNING WITH WEAK UPPER LEVEL LONGWAVE TROUGHING EXTENDING FROM THE WESTERN ATLC OVER THE GREATER ANTILLES AND NORTHERN LEEWARD ISLANDS. AT THE SURFACE...A 1022 MB HIGH IS CENTERED OVER THE W ATLC NEAR 30N74W 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. AN EARLIER ASCAT PASS AROUND 21/0238 UTC CAPTURED OCEAN WIND VECTOR RETRIEVALS INDICATING ENHANCEMENT OF THESE NE WINDS THROUGH THE WINDWARD PASSAGE. SIMILAR FILTERING OF NE WINDS ARE EXPECTED THROUGH THE MONA PASSAGE. THESE CONDITIONS ARE FORECAST TO PERSIST THROUGH LATE MONDAY AS THE RIDGE SHIFTS SLOWLY SE. OTHERWISE...LOW-LEVEL MOISTURE ASSOCIATED WITH A WEAKENED FRONTAL BOUNDARY TO THE NORTH OF PUERTO RICO AND THE LEEWARD ISLANDS IS ADVECTING ISOLATED SHOWERS OVER MUCH OF THE NE AND NORTH-CENTRAL CARIBBEAN THIS MORNING 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 1022 MB HIGH CENTERED IN THE SW NORTH ATLC NEAR 30N74W. INFLUENCE OF THE SURFACE RIDGE REMAINS MAINLY W OF 65W PROVIDING MOSTLY CLEAR SKIES AND FAIR CONDITIONS THIS MORNING FOR THE BAHAMAS AND THE FLORIDA PENINSULA. FARTHER EAST...AN UPPER LEVEL TROUGH IS ALONG 58W 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 ANALYZED FROM 28N51W TO 21N64W CONTINUES TO WEAKEN AS IT MOVES SOUTHEASTWARD AND LOSES THE UPPER LEVEL SUPPORT. THE SECOND REINFORCING COLD FRONT IS ANALYZED FROM 32N49W SW ALONG 26N54W TO 23N65W. PRE-FRONTAL SCATTERED SHOWERS AND TSTMS ARE LOCATED EAST OF THE FRONTS WITHIN 120 NM OF A SURFACE TROUGH FROM 21N55W TO 29N49W. SOUTH OF THE AFOREMENTIONED FRONTAL BOUNDARY...A SURFACE TROUGH IS ANALYZED EAST OF THE LESSER ANTILLES FROM NORTHERN GUYANA NEAR 06N58W TO 15N53W. ISOLATED SHOWERS AND TSTMS COVER A LARGE AREA WITHIN 300 NM EAST AND 150 NM WEST OF THE TROUGH...INCLUDING INLAND PORTIONS OF NORTHEASTERN SOUTH AMERICA. ELSEWHERE E OF 42W...A SURFACE RIDGE ANCHORED BY A 1031 MB HIGH CENTERED NORTH OF THE MADEIRA ISLANDS NEAR 35N18W CONTINUES TO PROVIDE MOSTLY FAIR CONDITIONS ACROSS THE EASTERN ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN