000 AXNT20 KNHC 192359 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI AUG 19 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... TROPICAL STORM HARVEY IS CENTERED NEAR 16.1W 84.6W OR ABOUT ABOUT 115 NM E OF ISLA ROATAN HONDURAS AND ABOUT 220 NM ESE OF BELIZE CITY MOVING W 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 998 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 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/WTNT22 KNHC FOR MORE DETAILS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERS THE AREA S OF 19N TO INLAND OVER HONDURAS BETWEEN 82W-87W. T.S. HARVEY IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 3-5 INCHES ACROSS HONDURAS...GUATEMALA...BELIZE AND THE YUCATAN PENINSULA OF MEXICO WITH POSSIBLE ISOLATED MAXIMUM AMOUNTS OF 8 INCHES. THESE RAINS COULD PRODUCE LIFE-THREATENING FLASH FLOODS AND MUDSLIDES...ESPECIALLY OVER HIGHER TERRAIN. A LARGE TROPICAL WAVE IS IN THE W TROPICAL ATLC IS ALONG 49W FROM 9N-17N WITH A 1007 MB LOW CENTERED NEAR 13N. SCATTERED MODERATE WITH EMBEDDED CLUSTERS OF OF SCATTERED STRONG CONVECTION COVERS THE AREA FROM 12N-17N BETWEEN 48W-55W. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BE CONDUCIVE FOR A TROPICAL DEPRESSION TO FORM OVER THE NEXT COUPLE OF DAYS. THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES GENERALLY WESTWARD NEAR 17 KT. INTERESTS IN THE LEEWARD ISLANDS SHOULD MONITOR THE PROGRESS OF THIS DISTURBANCE. LOCALLY HEAVY RAIN AND GUSTY WINDS ARE LIKELY OVER THE LEEWARD ISLANDS LATE SATURDAY INTO SUNDAY. THE TROPICAL WAVE BETWEEN THE W COAST OF AFRICA AND THE CAPE VERDE ISLANDS IS NOW A WELL DEFINED 1006 MB LOW CENTERED NEAR 14N20W. SCATTERED MODERATE/STRONG CONVECTION IS OVER THE CAPE VERDE ISLANDS FROM 15N-17N BETWEEN 21W-24W. ALTHOUGH UPPER LEVEL WINDS ARE CURRENTLY FAVORABLE FOR SOME DEVELOPMENT THIS SYSTEM IS EXPECTED TO ENCOUNTER A MORE STABLE ENVIRONMENT WITH DRIER AIR BY SUNDAY. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES TO THE W-NW AT 9-13 KT. REGARDLESS OF ANY DEVELOPMENT...LOCALLY HEAVY RAIN AND STRONG GUSTY WINDS ARE POSSIBLE IN THE CAPE VERDE ISLANDS TONIGHT THROUGH SATURDAY. ...TROPICAL WAVES... SEE SPECIAL FEATURES ABOVE. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE 1006 MB LOW IN THE SPECIAL FEATURES NEAR 14N20W ALONG 11N36W TO THE 1007 MB LOW ALSO IN THE SPECIAL FEATURES NEAR 13N49W. SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN 45 NM OF 10N BETWEEN 27W-30W WITH SCATTERED MODERATE STRONG CONVECTION COVERING THE REMAINDER OF THE AREA WITHIN 120 NM OF LINE FROM 11N24W TO 8N32W. SCATTERED MODERATE/ ISOLATED STRONG CONVECTION IS WITHIN 45/60 NM OF LINE FROM 8N45W TO 6N49W. SCATTERED MODERATE CONVECTION DOT IS WITHIN 45 NM OF 6N BETWEEN 34W-37W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER RIDGE CONTINUES TO DOMINATE THE GULF N OF 24N ANCHORED OVER W TEXAS. AN UPPER TROUGH EXTENDS FROM TUXPAN MEXICO E TO THE NW COAST OF THE YUCATAN PENINSULA NEAR MERIDA GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS INLAND OVER THE YUCATAN PENINSULA AND ISOLATED SHOWERS IN THE SW GULF FROM 21N-23N BETWEEN 93W-96W. A WEAK SURFACE TROUGH IS OVER THE W GULF ALONG 92W FROM 23N-25N. A WEAK SURFACE RIDGE DOMINATES THE N GULF. AN UPPER RIDGE ASSOCIATED WITH T.S. HARVEY EXTENDS OVER THE SE GULF GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND OVER CUBA AND WITHIN 45 NM ALONG THE COAST W OF 80W INTO THE YUCATAN CHANNEL. A SHORTWAVE UPPER TROUGH IS OFF THE E COAST OF FLORIDA GENERATING SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS FROM 24N-26N E OF 84W TO ACROSS S FLORIDA. THIS IS LEAVING THE REMAINDER OF THE GULF UNDER MOSTLY CLEAR SKIES THIS EVENING. THE WEAK SURFACE RIDGE WILL PREVAIL ACROSS THE N GULF THROUGH WED. CARIBBEAN SEA... THE PRIMARY CONCERN THIS EVENING IS T.S. HARVEY IN THE W CARIBBEAN...SEE SPECIAL FEATURES ABOVE. AN UPPER RIDGE ASSOCIATED WITH T.S. HARVEY COVERS THE W CARIBBEAN N OF 12N W OF 76W GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 15N W OF 76W. THE MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA NEAR 11N76W TO ACROSS NICARAGUA NEAR 12N84W INTO THE E PACIFIC REGION GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 11N-14N BETWEEN 80W-82W. A LARGE UPPER TROUGH IN THE CENTRAL ATLC EXTENDS S OVER THE E CARIBBEAN GENERATING ISOLATED SHOWERS N OF 15N BETWEEN 63W-75W LEAVING THE REMAINDER OF THE CARIBBEAN UNDER MOSTLY CLEAR SKIES THIS EVENING. THE 1007 MB LOW ALONG THE TROPICAL WAVE IN THE SPECIAL FEATURES WILL REACH THE LESSER ANTILLES EARLY SUN...POSSIBLY AS A TROPICAL CYCLONE...AND NEAR PUERTO RICO EARLY MON. ATLANTIC OCEAN... A SHORTWAVE UPPER TROUGH EXTENDS OFF THE E CONUS COAST THROUGH 32N74W TO THE BAHAMAS NEAR 25N77W GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120/150 NM OF LINE FROM FLORIDA NEAR FORT LAUDERDALE TO BEYOND 32N73W. A LARGE UPPER LEVEL TROUGH COVERS THE REMAINDER OF THE W ATLC AND INTO THE CENTRAL ATLC EXTENDING FROM BEYOND 32N56W THEN THROUGH AN UPPER LOW NEAR 26N61W ACROSS HISPANIOLA/PUERTO RICO TO OVER THE E CARIBBEAN SUPPORTING A SURFACE TROUGH THAT EXTENDS THROUGH 32N56W TO 28N61W. ISOLATED SHOWERS ARE WITHIN 90 NM OF LINE FROM 25N65W TO BEYOND 32N56W. THE REMAINDER OF THE ATLC BASIN IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1025 MB HIGH ABOUT 350 NM W OF THE AZORES WITH A SURFACE RIDGE AXIS EXTENDING ACROSS BERMUDA TO NEAR 29N79W WEAKENING ACROSS FLORIDA INTO THE N GULF OF MEXICO LEAVING THE REMAINDER OF THE ATLC UNDER FAIR CONDITIONS THIS EVENING. SAHARAN DRY AIR CONTINUES TO DOMINATE THE E AND CENTRAL ATLC N OF BOTH SPECIAL FEATURE LOWS WITHIN 250 NM OF LINE FROM NEAR 21N17W ALONG 17N34W TO 24N53W. THE SURFACE RIDGE EXTENDING FROM BERMUDA TO CENTRAL FLORIDA WILL GRADUALLY WEAKEN THROUGH MON. THE 1007 MB LOW ALONG A TROPICAL WAVE IN THE SPECIAL FEATURES WILL REACH THE W ATLC EARLY MON...POSSIBLY AS A TROPICAL CYCLONE...AND CONTINUE NW THROUGH WED. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW