000 AXNT20 KNHC 250558 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT THU AUG 25 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURE... HURRICANE IRENE IS CENTERED NEAR 24.2N 76.0W AT 25/0600 UTC OR ABOUT 91 NM ESE OF NASSAU AND ABOUT 660 NM S OF CAPE HATTERAS NORTH CAROLINA MOVING NW AT 10 KT. MINIMUM CENTRAL PRESSURE REPORTED BY THE AIR FORCE HURRICANE HUNTERS WAS 950 MB. MAXIMUM SUSTAINED WIND SPEED IS 100 KT WITH GUSTS TO 120 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. SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERS A BROAD AREA FROM 22N-27N BETWEEN 71W-77W. HURRICANE IRENE IS A LARGE TROPICAL CYCLONE WITH HURRICANE FORCE WINDS EXTENDING OUTWARD UP TO 60 NM FROM THE CENTER AND TROPICAL STORM FORCE WINDS EXTENDING OUTWARD UP TO 225 NM. IRENE IS EXPECTED TO PRODUCE RAINFALL ACCUMULATIONS OF 6 TO 12 INCHES OVER THE BAHAMAS DURING THE NEXT 36 HOURS. RAINS WILL BE DIMINISHING ACROSS THE TURKS AND CAICOS ISLANDS WITH ADDITIONAL RAINFALL AMOUNTS OF 1 TO 3 INCHES POSSIBLE...BRINGING THE MAXIMUM STORM TOTAL TO 6 TO 12 INCHES. A 1007 MB LOW IS CENTERED SW OF THE CAPE VERDE ISLANDS NEAR 12N28W WITH SCATTERED/NUMEROUS STRONG CONVECTION FROM 11N-14N BETWEEN 29W-33W. THIS SYSTEM IS BECOMING BETTER ORGANIZED AND A TROPICAL DEPRESSION COULD BE FORMING. IF CURRENT TRENDS CONTINUE ADVISORIES WILL LIKELY BE INITIATED LATER THIS MORNING. THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES WESTWARD OR WEST-NORTHWESTWARD AT 9-13 KT. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH IS ANALYZED ACROSS AFRICA ENTERING THE E TROPICAL ATLC NEAR 17N16W THROUGH THE 1007 MB LOW IN THE SPECIAL FEATURES TO NEAR 8N38W. THE ITCZ AXIS CONTINUES FROM 8N38W ALONG 7N50W TO INLAND OVER SOUTH AMERICA NEAR 7N59W. A SURFACE TROUGH IS JUST N OF THE ITCZ EXTENDING ALONG 49W FROM 11N-15N. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 120 NM OF LINE FROM 15N52W TO 9N58W. ...DISCUSSION... GULF OF MEXICO... AN UPPER RIDGE DOMINATES THE W GULF W OF 90W ANCHORED OVER W TEXAS. UPPER DIFFLUENCE OVER THE FAR NW GULF IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND OVER LOUISIANA AND E TEXAS AND ISOLATED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 60 NM ALONG THE N GULF COAST FROM THE FLORIDA PANHANDLE TO E TEXAS. AN UPPER LOW IS OVER THE NE GULF NEAR 27N86W WITH AN UPPER TROUGH EXTENDING S TO THE YUCATAN CHANNEL GENERATING ISOLATED SHOWERS/THUNDERSTORMS FROM 22N-27N BETWEEN 84W-88W. A WEAK SURFACE RIDGE REMAINS ACROSS THE FAR N GULF ANCHORED INLAND OVER THE SE CONUS. THIS IS LEAVING MOST OF THE GULF UNDER CLEAR SKIES TONIGHT. THE WEAK SURFACE RIDGE WILL LINGER OVER THE N GULF THROUGH FRI. HURRICANE IRENE CURRENTLY MOVING ACROSS THE BAHAMAS WILL REACH THE NW BAHAMAS ON THU WITH TROPICAL STORM CONDITIONS EXPECTED TO REMAIN WELL E OF THE GULF WATERS. HOWEVER...THE TIGHTENING PRESSURE GRADIENT WILL INCREASE WINDS AND SEAS OVER THE E GULF THU THROUGH LATE FRI. A WEAK COLD FRONT WILL REACH THE N GULF COAST EARLY SAT. CARIBBEAN SEA... HURRICANE IRENE CONTINUES TO GENERATE SCATTERED TO HEAVY SHOWERS WITH ISOLATED THUNDERSTORMS OVER THE N/CENTRAL CARIBBEAN MAINLY N OF 17N FROM THE VIRGIN ISLANDS TO CENTRAL CUBA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE OVER THE NW CARIBBEAN N OF 19N W OF 78W. A WEAK SURFACE TROUGH EXTENDS FROM THE COAST OF CUBA NEAR 21N77W ACROSS W JAMAICA ALONG 16N80W TO OFF THE COAST OF NICARAGUA NEAR 12N83W. BROAD OUTFLOW FROM HURRICANE IRENE COVERS THE E AND CENTRAL CARIBBEAN. THIS IS DRAWING TROPICAL MOISTURE N ACROSS THE S CARIBBEAN AND GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 13N TO INLAND OVER COLOMBIA BETWEEN 72W-76W. THIS UPPER FLOW IS ALSO RESPONSIBLE FOR THE HIGH DEBRIS CLOUDS COVERING THE AREA E OF 80W. HURRICANE IRENE OVER THE BAHAMAS IS EXPECTED TO MOVE AWAY FROM CARIBBEAN LATER TODAY. ATLANTIC OCEAN... THE PRIMARY CONCERN TONIGHT CONTINUES TO BE HURRICANE IRENE MOVING THROUGH THE BAHAMA ISLANDS TONIGHT...SEE SPECIAL FEATURES ABOVE. THE UPPER RIDGE ASSOCIATED WITH HURRICANE IRENE COVERS THE W ATLC W OF 65W. A LARGE UPPER LOW JUST TO THE E IS CENTERED NEAR 25N55W GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 120 NM OF LINE FROM 27N50W TO 24N57W. A WEAK 1015 MB SURFACE LOW IS CENTERED IN THE CENTRAL ATLC NEAR 23N45W GENERATING SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 24N-26N BETWEEN 44W-46W. THE REMAINDER OF THE ATLC BASIN N OF 25N E OF 65W IS DOMINATED BY A LARGE SURFACE RIDGE ANCHORED BY A 1026 MB HIGH N OF THE DISCUSSION AREA ABOUT 450 NM WSW OF THE AZORES. HURRICANE IRENE IS FORECAST TO MOVE MORE N-NW ACROSS CENTRAL BAHAMAS TONIGHT AND INTENSIFY AS IT REACHES THE N BAHAMAS EARLY THU THEN N OF THE BAHAMAS ON ON FRI BEFORE MOVING N OF AREA FRI EVENING. ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW