000 AXNT20 KNHC 212343 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2300 UTC. ...SPECIAL FEATURES... TROPICAL STORM BRET IS CENTERED NEAR 34.2N 69.7W AS OF 2100 UTC MOVING ENE AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. MAXIMUM SUSTAINED WIND SPEED IS 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 MODERATE CONVECTION IS S OF THE CENTER FROM 32N-34N BETWEEN 70W-73W...AND FROM 27N-31N BETWEEN 66W-70W. TROPICAL STORM CINDY IS CENTERED NEAR 42.3N 45.0W AS OF 2100 UTC MOVING NE AT 24 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1002 MB. MAXIMUM SUSTAINED WIND SPEED IS 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 CONVECTION IS FROM 41N-43N BETWEEN 43W-48W. ...TROPICAL WAVES... TROPICAL WAVE IN THE ERN TRPCL ATLC EXTENDS S OF THE CAPE VERDE ISLANDS ALONG 13N25W TO 5N28W MOVING W AT 15-20 KT. SATELLITE IMAGERY AND SATELLITE DERIVED WINDS INDICATE CLEAR CYCLONIC FLOW IS AROUND THE WAVE AXIS. WHILE THERE IS NOT A RIDGE OF DEEP LAYER MOISTURE ASSOCIATED WITH THE WAVE...ENHANCED VALUES ARE SURROUNDING THE AXIS. SCATTERED MODERATE/STRONG CONVECTION IS FROM 10N-12N BETWEEN 26W-28W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 6N-8N BETWEEN 23W-30W. TROPICAL WAVE EXTENDS E OF THE WINDWARD ISLANDS ALONG 17N49W 11N52W 7N52W MOVING W NEAR 20 KT. SATELLITE IMAGERY INDICATES BROAD CYCLONIC FLOW IS AROUND THE WAVE AXIS. TOTAL PRECIPITABLE WATER IMAGERY ALSO SHOWS A SURGE OF DEEP LAYER MOISTURE IS AROUND THE AXIS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 12N-19N BETWEEN 46W-53W. TROPICAL WAVE IS ACROSS THE NW CARIBBEAN AND WRN CUBA ALONG 24N81W TO 17N82W MOVING WNW NEAR 15 KT. THE WAVE IS EMBEDDED WITHIN WIDESPREAD MODERATE MOISTURE ACROSS MUCH OF THE WRN CARIBBEAN. WAVE LOCATION IS DIFFICULT TO DETERMINE AND IS CURRENTLY BASED ON CONTINUITY AND SURFACE OBSERVATIONS IN THE NW CARIBBEAN. ISOLATED MODERATE CONVECTION IS WITHIN 100 NM EITHER SIDE OF THE WAVE AXIS. STRONGER ACTIVITY IS ALL ACROSS CUBA AS WELL. HOWEVER...THIS IS MORE A RESULT OF DAYTIME HEATING THAN THE WAVE. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA FROM THE PRIME MERIDIAN AT 16N ALONG 15N4W 17N12W ACROSS SENEGAL TO 11N22W. THE ITCZ PICKS UP ON THE OTHER SIDE OF A TROPICAL WAVE ALONG 7N31W TO 7N45W. ISOLATED MODERATE/STRONG CONVECTION IS FROM 2N-7N BETWEEN 30W-40W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-7N BETWEEN 44W-49W. ...DISCUSSION... GULF OF MEXICO... MUCH OF THE GULF OF MEXICO IS UNDER FAIR WEATHER THIS EVENING DUE TO THE COMBINATION OF WEAK SURFACE RIDGING ALONG 26N AND DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE CENTERED OVER TENNESSEE. LIGHT ANTI-CYCLONIC FLOW IS AROUND THE RIDGE WITH STRONGER SE WINDS UP TO 20 KTS ACROSS THE NE MEXICO COAST. TYPICAL AFTERNOON SHOWERS/THUNDERSTORMS ARE STILL ACROSS PORTIONS OF S FLORIDA DUE TO DAYTIME HEATING. A FEW ISOLATED SHOWERS ARE IN THE NE GULF N OF 26N E OF 91W. A TROPICAL WAVE S OF THE FLORIDA PENINSULA ACROSS WRN CUBA AND THE NW CARIBBEAN MAY ENHANCE CONVECTION ACROSS THE SE GULF AND YUCATAN PENINSULA OVER THE NEXT DAY OR SO AS IT MOVES W OR WNW. WEAK SURFACE RIDGING IS EXPECTED TO REMAIN ACROSS THE REMAINDER OF THE BASIN. CARIBBEAN SEA... A TROPICAL WAVE IN THE NW CARIBBEAN IS BRINGING A FEW ISOLATED SHOWERS/THUNDERSTORMS TO THIS AREA N OF 17N BETWEEN 80W-84W. STRONGER SHOWERS/THUNDERSTORMS ARE ACROSS MUCH OF CUBA DUE TO DAYTIME HEATING. SOME OF THIS ACTIVITY MAY BE ENHANCED BY AN UPPER LEVEL LOW THAT IS SPINNING OVER ERN CUBA NEAR 20N75W. A WEAK UPPER TROUGH IS ALSO OVER THE WINDWARD ISLANDS...BUT IS EMBEDDED WITH VERY DRY AIR. THIS DRY AIR IS MAINTAINING MOSTLY FAIR WEATHER ACROSS THE REMAINDER OF THE BASIN. A FEW AFTERNOON CONVECTIVE SHOWERS/THUNDERSTORMS ARE ACROSS HISPANIOLA AND PUERTO RICO. SIMILAR ACTIVITY IS ACROSS HONDURAS...NICARAGUA...AND PANAMA. SOME OF THE ACTIVITY ACROSS PANAMA IS INFLUENCED BY THE MONSOON TROUGH EXTENDING FROM THE E PACIFIC ACROSS COSTA RICA TO NRN COLOMBIA. ELY TRADEWINDS OF 20-25 KTS ARE ACROSS MUCH OF THE ERN CARIBBEAN. EXPECT THE TROPICAL WAVE IN THE NW CARIBBEAN TO MOVE OUT OF THE AREA OVER THE NEXT DAY OR. A TROPICAL WAVE E OF THE WINDWARD ISLANDS WILL PROBABLY BEGIN IMPACTING THE ISLANDS WITHIN THE NEXT 24 HRS BRINGING SHOWERS/THUNDERSTORMS...SOME HEAVY AT TIMES. ATLANTIC OCEAN... EVEN THOUGH TROPICAL STORM BRET IS N OF THE DISCUSSION AREA...SHOWERS/THUNDERSTORMS ASSOCIATED WITH THE SYSTEM ARE IMPACTING THE AREA N OF 26N BETWEEN 64W-72W. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE NW BAHAMAS. THE REMAINDER OF THE BASIN IS DOMINATED BY A BROAD SURFACE RIDGE ANCHORED AROUND A 1032 MB AZORES HIGH NEAR 39N32W PROVIDING FAIR WEATHER BASIN-WIDE. ALOFT...AN UPPER LEVEL RIDGE EXTENDS OVER THE FAR WRN ATLC FROM THE ERN CONUS. AN UPPER LEVEL TROUGH IS TO THE E N OF 29N. AN UPPER LEVEL RIDGE EXTENDS FROM NEAR 46N36W TO AN ANTI-CYCLONIC CENTER NEAR 21N49W. AN UPPER TROUGH EXTENDS FROM THE AZORES ISLANDS TO NEAR 24N38W. A SECOND ANTI-CYCLONIC CENTER IS JUST N OF THE CAPE VERDE ISLANDS NEAR 21N26W...WHILE ANOTHER UPPER LEVEL TROUGH COVERS THE FAR E ATLC EXTENDING FROM PORTUGAL TO THE CANARY ISLANDS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON