000 AXNT20 KNHC 202354 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT AUG 20 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... THE LARGE TROPICAL WAVE IN THE W TROPICAL ATLC HAS BEEN UPGRADED TO TROPICAL STORM IRENE AT 20/2300 UTC. T.S. IRENE IS CENTERED NEAR 14.9N 58.5W AT 20/2300 UTC OR ABOUT 165 NM E OF DOMINICA AND ABOUT 190 NM ESE OF GUADELOUPE MOVING W AT 19 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 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 STRONG CONVECTION IS FROM 14N-17N BETWEEN 55W-59W. SCATTERED MODERATE/ STRONG CONVECTION IS IN A BAND WITHIN 75/90 NM OF LINE FROM 17N53W N OF THE SYSTEM NEAR 19N58W OVER THE LEEWARD ISLANDS INTO THE E CARIBBEAN NEAR ALONG 15N63W TO JUST W OF THE WINDWARD ISLANDS NEAR 12N62W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS DOT THE REMAINDER OF THE AREA FROM 12N-20N BETWEEN 51W-64W INCLUDING THE REMAINDER OF THE LESSER ANTILLES. IRENE IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 4-7 INCHES IN THE LEEWARD ISLANDS...PUERTO RICO AND THE VIRGIN ISLANDS...WITH ISOLATED MAXIMUM AMOUNTS OF UP TO 10 INCHES. THESE RAINS COULD CAUSE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES IN AREAS OF STEEP TERRAIN. TROPICAL STORM HARVEY MADE LANDFALL EARLIER THIS AFTERNOON NEAR DANGRIGA TOWN BELIZE. HARVEY IS CENTERED INLAND NEAR 17.3W 89.5W AT 21/0000 UTC OR ABOUT 35 NM NE OF TIKAL GUATEMALA AND ABOUT 70 NM W OF BELIZE CITY MOVING W-NW AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. PLEASE SEE THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER MIATCPAT3/WTNT33 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT3/ WTNT23 KNHC FOR MORE DETAILS. SCATTERED MODERATE/STRONG CONVECTION IS INLAND OVER THE YUCATAN PENINSULA INCLUDING BELIZE AND N GUATEMALA MOVING INTO THE BAY OF CAMPECHE WITHIN 45 NM ALONG THE COAST S OF 21N E OF CIUDAD DEL CAMPECHE. SCATTERED MODERATE WITH EMBEDDED ISOLATED STRONG CONVECTION COVERS THE NW CARIBBEAN FROM 18N-22N W OF 81W TO THE COAST OF THE YUCATAN. HARVEY IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 3-6 INCHES ACROSS BELIZE...GUATEMALA...HONDURAS...AND THE YUCATAN PENINSULA OF MEXICO...WITH POSSIBLE ISOLATED MAXIMUM AMOUNTS OF 10 INCHES. THESE RAINS COULD PRODUCE LIFE THREATENING FLASH FLOODS AND MUDSLIDES...ESPECIALLY OVER HIGHER TERRAIN. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS OFF THE COAST OF W AFRICA NEAR 17N16W CONTINUING NW ALONG 19N20W THEN SW THROUGH THE 1007 MB LOW IN THE SPECIAL FEATURES NEAR 16N26W THEN TO 9N41W. WITH LOW LEVEL WINDS DRAWN NORTHWARD INTO THE NEWLY DEVELOPED T.S. IRENE IN THE SPECIAL FEATURES...THERE IS NO CONVERGENCE OF NE AND SE TRADE WINDS...THUS THERE IS NO ITCZ DEPICTED ON THE SURFACE ANALYSIS. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE WITHIN 75 NM OF 8N BETWEEN 31W-39W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 14N-17N BETWEEN 18W-21W WITH CLUSTERS OF SIMILAR CONVECTION WITHIN 75 NM OF LINE FROM 7N42W TO 10N53W. ...DISCUSSION... GULF OF MEXICO... THE BROAD UPPER RIDGE CONTINUES TO DOMINATE THE GULF N OF 24N ANCHORED OVER CENTRAL TEXAS. THE UPPER RIDGE ASSOCIATED WITH T.S. HARVEY EXTENDS OVER THE S GULF GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 26N BETWEEN BETWEEN 82W-90W TO INLAND OVER W CUBA AND THROUGH THE YUCATAN CHANNEL. A WEAK SURFACE RIDGE REMAINS ACROSS THE N GULF EXTENDING FROM THE W ATLC. AFTERNOON SHOWERS/THUNDERSTORMS HAVE DEVELOPED INLAND OVER FLORIDA MOVING TO ALONG THE IMMEDIATE COAST FROM NAPLES TO JUST N OF CEDAR KEY. THIS IS LEAVING THE REMAINDER OF THE GULF UNDER MOSTLY CLEAR SKIES THIS EVENING. HOWEVER...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO INCREASE ACROSS THE S GULF AS HARVEY MOVES ACROSS GUATEMALA TONIGHT. HARVEY WILL THEN WEAKEN TO A TROPICAL DEPRESSION OVER MEXICO SUN AND DISSIPATE SUN NIGHT. CARIBBEAN SEA... THE PRIMARY CONCERN THIS EVENING IS NEWLY DEVELOPED T.S. IRENE APPROACHING THE LESSER ANTILLES AND T.S. HARVEY MOVING ACROSS CENTRAL AMERICA...SEE SPECIAL FEATURES ABOVE. AN UPPER RIDGE ASSOCIATED WITH T.S. HARVEY COVERS THE W CARIBBEAN W OF 80W. THE DEVELOPING UPPER RIDGE ASSOCIATED WITH T.S. IRENE COVERS THE FAR E CARIBBEAN WITH AN UPPER LOW OVER THE CENTRAL CARIBBEAN GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 16N TO OVER HISPANIOLA...E CUBA...AND JAMAICA. THE MONSOON TROUGH EXTENDS ACROSS THE FAR SW CARIBBEAN FROM COLOMBIA NEAR 10N76W ALONG THE N COAST OF PANAMA NEAR COLON TO OVER COSTA RICA NEAR THE NW BORDER OF PANAMA GENERATING SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS INLAND AND ALONG THE IMMEDIATE COAST OF COLOMBIA AND W PANAMA. HARVEY WILL WEAKEN TO A TROPICAL DEPRESSION OVER MEXICO SUN AND DISSIPATE SUN NIGHT. T.S. IRENE IS FORECAST TO MOVE INTO NE CARIBBEAN SUN NIGHT AND MON THEN TO NEAR WINDWARD PASSAGE ON TUE. ATLANTIC OCEAN... THE PRIMARY CONCERN THIS EVENING IS NEWLY DEVELOPED T.S. IRENE APPROACHING THE LESSER ANTILLES COVERING PORTIONS OF THE W TROPICAL ATLC...SEE SPECIAL FEATURES ABOVE. A 1007 MB LOW IS JUST W OF THE CAPE VERDE ISLANDS CENTERED NEAR 16N26W AND HAS A LOW CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 200 NM OF LINE FROM 18N23W TO 11N33W. LOCALLY HEAVY RAINS AND GUSTY WINDS WILL CONTINUE TO AFFECT PARTS OF THE CAPE VERDE ISLANDS OVERNIGHT. THE REMAINDER OF THE ATLC BASIN N OF 20N IS DOMINATED BY A BROAD SURFACE RIDGE ANCHORED BY A 1026 MB HIGH N OF THE DISCUSSION AREA WSW OF THE AZORES AND A RIDGE AXIS EXTENDING ACROSS BERMUDA TO NE FLORIDA NEAR JACKSONVILLE THEN WEAKENING ACROSS THE N GULF OF MEXICO LEAVING THE REMAINDER OF THE ATLC UNDER FAIR CONDITIONS THIS EVENING. T.S. IRENE IS FORECAST TO MOVE ACROSS THE W TROPICAL ATLC THEN INTO THE NE CARIBBEAN SUN NIGHT. IRENE WILL THEN MOVE NEAR WINDWARD PASSAGE ON TUE TO OVER CUBA WED AND STRAITS OF FLORIDA ON THU. THE SURFACE RIDGE WILL GRADUALLY WEAKEN THROUGH MON. 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