000 AXNT20 KNHC 211801 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU JUL 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1745 UTC. ...SPECIAL FEATURES... THE CENTER OF TROPICAL STORM BRET AT 21/1500 UTC WAS NEAR 33.8N 70.6W. BRET IS MOVING NORTHEASTWARD AT 08 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 35 KT WITH GUSTS TO 45 KT. PUBLIC ADVISORIES ON BRET ARE ISSUED UNDER WMO HEADER WTNT32 KNHC AND UNDER AWIPS HEADER MIATCPAT2. FORECAST/ ADVISORIES ARE ISSUED UNDER WMO HEADER WTNT22 KNHC AND UNDER AWIPS HEADER MIATCMAT2. SCATTERED HEAVY SHOWERS AND THUNDERSTORMS ARE FROM 26N TO 34N BETWEEN 68W-72W. THE CENTER OF TROPICAL STORM CINDY AT 21/1500 UTC WAS NEAR 40.3N 47.3W. CINDY IS MOVING NORTHEASTWARD 25 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1002 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 50 KT WITH GUSTS TO 60 KT. PUBLIC ADVISORIES ON CINDY ARE ISSUED UNDER WMO HEADER WTNT33 KNHC AND UNDER AWIPS HEADER MIATCPAT3. FORECAST/ADVISORIES ARE ISSUED UNDER WMO HEADER WTNT23 KNHC AND UNDER AWIPS HEADER MIATCMAT3. SCATTERED MODERATE TO STRONG RAINSHOWERS AND THUNDERSTORMS ARE WITHIN 90-150 NM AROUND THE CENTER. ...TROPICAL WAVES... A TROPICAL WAVE IS IN THE EASTERN TROPICAL ATLC S OF CAPE VERDE ISLANDS ANALYZED FROM 12N23W TO 5N26W...MOVING W AT 15-20 KT. THIS WAVE IS EMBEDDED WITHIN A REGION OF ELEVATED VALUES OF MOISTURE ON TOTAL PRECIPITABLE WATER PRODUCT. LOW LEVEL CLOUD CYCLONIC TURNING IS VERY WELL OBSERVED ON VISIBLE SATELLITE IMAGERY...AS WELL AS AN EARLIER ASCAT PASS AND LOW LEVEL SATELLITE DERIVED WINDS. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 4N-12N BETWEEN 22W-30W. THIS AREA OF CONVECTION IS ALSO RELATED TO THE ITCZ. A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL ATLC WITH AXIS ANALYZED FROM 16N47W TO 6N50W MOVING W AT 15-20 KT. THIS WAVE MOVES ALONG THE LEADING EDGE OF A DEEP MOISTURE SURGE ON TPW. LOW LEVEL CLOUD CYCLONIC TURNING IS VERY CLEAR ON VISIBLE SATELLITE IMAGERY AND DERIVED WINDS. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 200 NM W OF THE AXIS N OF 11N. A TROPICAL WAVE IS MOVING ACROSS THE NW CARIBBEAN WITH AXIS ANALYZED FROM NEAR 23N80W TO 18N81W. THE MOISTURE ASSOCIATED TO THIS WAVE IS LIMITED AND ASSOCIATED TO AN UPPER LEVEL CYCLONIC CIRCULATION CENTERED IN THE WINDWARD PASSAGE. CYCLONIC TURNING IS VERY SUBTLE AROUND THE WAVE AXIS. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 90 NM ON EITHER SIDE OF ITS AXIS. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS OVER AFRICA AND BRIEFLY ENTERS THE ATLC OCEAN FROM THE COAST OF SENEGAL NEAR 15N17W TO 12N20W. THE ITCZ CONTINUES W OF A TROPICAL WAVE FROM 7N29W TO 8N42W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 100/150 NM ON EITHER SIDE OF THE ITCZ AXIS. THIS AREA OF CONVECTION IS ALSO CONFINED TO THE TROPICAL WAVE MENTIONED ABOVE. ...DISCUSSION... GULF OF MEXICO... THE UPPER LEVELS OF THE ATMOSPHERE ACROSS THE GULF ARE RELATIVELY DRY WITH MODERATE SUBSIDENCE NOTICED ON WATER VAPOR IMAGERY. AT SURFACE...THE PRESSURE GRADIENT IS COMPARATIVELY FLAT GENERATING A WEAK ANTICYCLONIC FLOW OBSERVED ACROSS THE AREA...WITH LOW TOP ISOLATED SHOWERS EMBEDDED IN THE FLOW N OF 26N E OF 93W. SOME OF THESE SHOWERS MAY BECOME STRONG THROUGHOUT THE LATE AFTERNOON HOURS...ESPECIALLY THOSE CLOSE TO THE COASTAL WATERS OF LOUISIANA. NO SIGNIFICANT DEEP CONVECTIVE PRECIP IS FOUND ELSEWHERE ACROSS THE BASIN. A TROPICAL WAVE CURRENTLY MOVING ACROSS THE NW CARIBBEAN BASIN WILL ENTER THE FAR SE GULF IN THE NEXT 6-12 HOURS...BRINGING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TO THE FLORIDA STRAITS E OF 83W. CARIBBEAN SEA... A TROPICAL WAVE IS MOVING ACROSS THE NW BASIN ANALYZED FROM NEAR 23N80W TO 18N81W GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 90 NM ON EITHER SIDE OF ITS AXIS. THIS WAVE IS ALSO INTERACTING WITH AN UPPER LEVEL CYCLONIC CIRCULATION CENTERED IN THE WINDWARD PASSAGE. THE WAVE WILL CONTINUE TO TRACK WNW WITH LIMITED ACTIVITY DURING THE NEXT 24 HOURS. SIMILAR CONVECTION IS FOUND IN THE FAR SW BASIN...WITHIN 70 NM OFF THE COAST OF COLOMBIA...PANAMA...AND COSTA RICA...DUE TO CLOSE PROXIMITY TO THE MONSOON TROUGH ANALYZED ACROSS CENTRAL AMERICA INTO NORTHERN COLOMBIA. FAIR WEATHER CONDITIONS ARE OBSERVED ACROSS THE REMAINDER OF THE CARIBBEAN...WITH EASTERLY TRADE WINDS RANGING FROM 10-20 KT. THE MONSOON TROUGH IS EXPECTED TO LIFT N WITHIN THE NEXT 24-36 HOURS WITH CONVECTION EXPANDING ACROSS THE SW BASIN AND INLAND PORTIONS OF CENTRAL AMERICA REACHING TO NORTHERN NICARAGUA. IN THE MEAN TIME...A TROPICAL WAVE CURRENTLY IN THE CENTRAL TROPICAL ATLC WILL BEGIN TO AFFECT THE LESSER ANTILLES IN THE NEXT 24 HOURS. ATLANTIC OCEAN... SCATTERED HEAVY SHOWERS AND THUNDERSTORMS EXTEND INTO OUR DISCUSSION AREA S OF TROPICAL STORM BRET FROM 26N TO 34N BETWEEN 68W-72W. THIS AREA OF CONVECTION IS EXPECTED TO MOVE NE OUT OF OUR AREA OVER THE NEXT 24 HOURS. A BROAD SURFACE RIDGE DOMINATED THE REMAINDER OF THE ATLC N OF 17N...ANCHORED BY A 1034 MB HIGH W OF THE AZORES NEAR 39N32W...LEAVING THE REMAINDER OF THE DISCUSSION AREA WITH FAIR WEATHER THIS AFTERNOON. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA