000 AXNT20 KNHC 250006 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED AUG 24 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURE... MAJOR HURRICANE IRENE IS CENTERED NEAR 23.5N 75.0W AT 25/0000 UTC OR ABOUT 160 NM...295 KM SE OF NASSAU IN THE BAHAMAS...OR ABOUT 705 NM...1300 KM S OF CAPE HATTERAS NORTH CAROLINA. MOVING NW AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 954 MB. MAXIMUM SUSTAINED WIND SPEED IS 105 KT WITH GUSTS TO 130 KT. PLEASE SEE THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER MIATCPAT4/WTNT34 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. NUMEROUS STRONG CONVECTION IS WITHIN 150 NM OF THE CENTER. TOTAL PRECIPITABLE WATER IMAGERY INDICATES VERY MOIST CONDITIONS AT LEAST 250 NM FROM THE CENTER...WITH DRIER AIR IN THE WESTERN SEMICIRCLE PERIPHERY. HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 50 NM FROM THE CENTER AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 200 NM FROM THE CENTER. IRENE IS A MAJOR HURRICANE. SOME ADDITIONAL STRENGTHENING IS FORECAST FOR THE NEXT 24 HOURS. A 1007 MB LOW IS CENTERED ABOUT 250 NM SW OF THE CAPE VERDE ISLANDS NEAR 13N27W WITH SCATTERED MODERATE TO STRONG CONVECTION WITHIN 150 NM OF THE CENTER. SHOWER/THUNDERSTORM ACTIVITY HAS INCREASED IN ORGANIZATION ENVIRONMENTAL CONDITIONS APPEAR GENERALLY CONDUCIVE FOR DEVELOPMENT OF THIS LOW INTO A TROPICAL CYCLONE IN THE NEXT TWO DAYS. THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD AT AROUND 10 KT. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH IS ANALYZED ACROSS AFRICA ENTERING THE E TROPICAL ATLC NEAR 19N16W. THE MONSOON TROUGH CONTINUES TO THE 1007 MB LOW AT 13N27W TO NEAR 10N35W. THE ITCZ AXIS EXTENDS FROM THERE TO 13N48W TO 13N52W. SCATTERED MODERATE TO STRONG CONVECTION IS OCCURING WITHIN 150 NM OF THE CENTER OF THE LOW. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM N OF THE ITCZ AXIS W OF 47W. ...DISCUSSION... GULF OF MEXICO... WITH ALMOST NO SURFACE PRESSURE GRADIENT...THE WINDS ACROSS THE GULF ARE VERY WEAK THIS EVENING WITH MAX OF 10 KT E IN THE NEAR THE U.S. GULF COAST. ISOLATED SHOWERS AND THUNDERSTORMS ARE OCCURRING OVER THE GULF...BUT NO CONCENTRATED OR ORGANIZED CONVECTION TO BE FOUND. IN THE UPPER LEVELS...A LOW IS PRESENT OVER THE NE GULF OF MEXICO WITH A TROUGH AXIS EXTENDING SW TO THE YUCATAN OF MEXICO. DURING THE NEXT DAY...THE SURFACE WINDS WILL INCREASE TO 10-15 KT AND WILL BACK TO A NORTHEASTERLY DIRECTION. WITH HURRICANE IRENE REMAINING EAST OF THE FLORIDA PENINSULA...SUBSIDENCE FROM THE HURRICANE WILL CONTRIBUTE TO KEEPING CONVECTION TO A MINIMUM OVER THE GULF. CARIBBEAN SEA... RAINBANDS ASSOCIATED WITH HURRICANE IRENE ARE PROVIDING SOME PRECIPITATION OVER THE NORTH CENTRAL CARIBBEAN SEA AND OVER PUERTO RICO AND HISPANIOLA. LIKEWISE THE LARGE CIRCULATION OF THE HURRICANE HAS CAUSED THE NORMAL TRADEWIND REGIME TO BE DISRUPTED. IN THE NW CARIBBEAN...WEAK NORTHERLY WINDS ARE OCCURRING AND IN THE SW AND CENTRAL CARIBBEAN WEAK SW WINDS ARE OBSERVED. A 1500Z ASCAT PASS AND SOME SHIPS INDICATE THAT SW WINDS TO 30 KT ARE OCCURRING IN THE WINDWARD PASSAGE. AS THE HURRICANE MOVES TOWARD THE NW AWAY FROM THE CARIBBEAN DURING THE NEXT DAY...CONVECTION AND WINDS SHOULD DIMINISH AND CONDITIONS RETURN TO MORE TYPICAL SUMMERTIME REGIME BY LATE FRIDAY. IN THE UPPER LEVELS...THE NE OUTFLOW FROM IRENE PREVAILS AND IS ADVECTING UPPER LEVEL MOISTURE AND CIRRUS ACROSS THE EASTERN AND CENTRAL CARIBBEAN. ATLANTIC OCEAN... THE CIRCULATION AROUND MAJOR HURRICANE IRENE IS BECOMING QUITE LARGE WITH 20 KT WINDS EXTENDING NEARLY 600 NM ACROSS. AS THE HURRICANE IS CURRENTLY CENTERED OVER THE CENTRAL BAHAMAS...HEAVY RAIN WILL CONTINUE OVER THE CENTRAL AND NORTHWESTERN BAHAMAS THIS EVENING AND TOMORROW...WHILE THE SOUTHEASTERN BAHAMAS WILL SEE DIMINISHING RAINFALL. A WEAK 1014 MB LOW IS CENTERED NEAR 23N44W. THIS LOW REACQUIRED SCATTERED MODERATE CONVECTION EARLIER TODAY...BUT IS NEARLY NON-EXISTENT AGAIN THIS EVENING. THIS SYSTEM HAS VERY LITTLE CHANCE TO BECOME A TROPICAL CYCLONE. MOST OF THE TROPICAL NORTH ATLANTIC HAS WEAK TO MODERATE EASTERLY TRADEWINDS UNDER THE INFLUENCE OF A 1027 MB HIGH AT 35N38W. IN THE UPPER LEVELS...RIDGING EXTENDS WESTWARD FROM WEST AFRICA ALONG 20N TO 45W. A STRONG UPPER LOW IS CENTERED NEAR 24N53W. SW WINDS ON THE EASTERN SIDE OF THIS UPPER LOW IS PROVIDING SUBSTANTIAL VERTICAL SHEAR OVER THIS AFOREMENTIONED LOW. ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LANDSEA