000 AXNT20 KNHC 291201 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI JUL 29 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...SPECIAL FEATURES... THE CENTER OF TROPICAL STORM DON IS NEAR 25.7N 94.3W AT 29/1200 UTC. THIS POSITION FOR DON ALSO IS ABOUT 255 MILES/395 KM TO THE SOUTHEAST OF CORPUS CHRISTI TEXAS. DON IS MOVING TOWARD THE WEST-NORTHWEST AT 12 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 45 KT WITH GUSTS TO 55 KT. THE INTERMEDIATE PUBLIC ADVISORY FOR DON IS ISSUED UNDER THE WMO HEADER WTNT34 KNHC AND UNDER THE AWIPS HEADER MIATCPAT4. THE FORECAST/ADVISORY FOR DON IS ISSUED UNDER THE WMO HEADER WTNT24 KNHC AND UNDER THE AWIPS HEADER MIATCMAT4. NUMEROUS STRONG RAINSHOWERS AND THUNDERSTORMS ARE WITHIN AN 85 NM RADIUS OF 24.5N94W. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 16N40W 12N41W TO 8N41W. A 1008 MB LOW PRESSURE CENTER IS NEAR 8N41W. AN INVEST WAS STARTED ON THE 8N41W LOW PRESSURE CENTER AT 29/0600 UTC FOR THE PURPOSE OF STARTING GUIDANCE ON IT. STRONG RAINSHOWERS AND THUNDERSTORMS ARE FROM 2N TO 8N BETWEEN 37W AND 39W...AND FROM 8N TO 10N BETWEEN 41W AND 44W. ISOLATED MODERATE RAINSHOWERS ARE FROM 10N TO 13N BETWEEN 34W AND 44W. THIS AREA OF DISTURBED WEATHER IS SHOWING SIGNS OF ORGANIZATION...AND ENVIRONMENTAL CONDITIONS ARE CONDUCIVE FOR GRADUAL DEVELOPMENT DURING THE NEXT FEW DAYS. IT IS POSSIBLE THAT THIS SYSTEM MAY BECOME A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES WESTWARD OR WEST- NORTHWESTWARD 15 TO 20 MPH. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 20N21W 16N232W 11N24W. ISOLATED MODERATE RAINSHOWERS ARE FROM 10N TO 12N BETWEEN 20W AND 25W. A TROPICAL WAVE STARTS IN THE ATLANTIC OCEAN NEAR 23N68W. IT CROSSES THE WESTERN PART OF THE DOMINICAN REPUBLIC...TO 16N72W IN THE CARIBBEAN SEA...TO NORTHEASTERN COASTAL COLOMBIA ALONG 11N BETWEEN 72W AND 73W. HISPANIOLA IS IN THE AREA OF AN UPPER LEVEL SHEAR AXIS. RAINSHOWERS ARE POSSIBLE FROM THE NETHERLANDS ANTILLES TO THE COASTAL WATERS AND POSSIBLY COASTAL PLAINS OF HISPANIOLA...PUERTO RICO...AND THE VIRGIN ISLANDS BETWEEN 64W AND 74W. AN UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 16N79W. RAINSHOWERS COVER THE WINDWARD PASSAGE AND WESTWARD...TO THE NORTH OF 18N BETWEEN THE WINDWARD PASSAGE AND 84W...AND FROM 14N TO 17N BETWEEN 80W AND 83W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH THE PRIME MERIDIAN ALONG 18N TO 23N11W 15N17W TO 13N22W. THE ITCZ CONTINUES FROM 13N24W TO 9N38W 8N42W...INTO NORTH CENTRAL FRENCH GUIANA. ISOLATED MODERATE RAINSHOWERS AND POSSIBLE THUNDERSTORMS ARE FROM 4N TO 10N BETWEEN 23W AND 33W...AND ELSEWHERE TO THE SOUTH OF 10N TO THE WEST OF 40W. ...DISCUSSION... GULF OF MEXICO... TROPICAL STORM DON IS THE MAIN ATTRACTION AT THIS MOMENT. AN UPPER LEVEL INVERTED TROUGH HAS MOVED INTO THE EASTERN GULF OF MEXICO ALONG 85W/86W FROM THE FLORIDA BIG BEND AND FLORIDA PANHANDLE SOUTHWARD BEYOND THE YUCATAN CHANNEL. NO SIGNIFICANT DEEP CONVECTIVE PRECIPITATION ACCOMPANIES THIS TROUGH. THE WESTERN END OF A SURFACE RIDGE CROSSES FLORIDA ALONG 30N INTO BEYOND THE FLORIDA PANHANDLE. CARIBBEAN SEA... A TROPICAL WAVE STARTS IN THE ATLANTIC OCEAN NEAR 23N68W. IT CROSSES THE WESTERN PART OF THE DOMINICAN REPUBLIC...TO 16N72W IN THE CARIBBEAN SEA...TO NORTHEASTERN COASTAL COLOMBIA ALONG 11N BETWEEN 72W AND 73W. HISPANIOLA IS IN THE AREA OF AN UPPER LEVEL SHEAR AXIS. RAINSHOWERS ARE POSSIBLE FROM THE NETHERLANDS ANTILLES TO THE COASTAL WATERS AND POSSIBLY COASTAL PLAINS OF HISPANIOLA...PUERTO RICO...AND THE VIRGIN ISLANDS BETWEEN 64W AND 74W. AN UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 16N79W. RAINSHOWERS COVER THE WINDWARD PASSAGE AND WESTWARD...TO THE NORTH OF 18N BETWEEN THE WINDWARD PASSAGE AND 84W...AND FROM 14N TO 17N BETWEEN 80W AND 83W. THE TROUGH CONTINUES FROM THE 16N79W CYCLONIC CENTER TO SOUTHEASTERN COASTAL NICARAGUA. THE MONSOON TROUGH PASSES THROUGH NORTHERN COASTAL COLOMBIA NEAR 10N76W BEYOND SOUTHERN COSTA RICA INTO THE EASTERN PACIFIC OCEAN. SCATTERED TO NUMEROUS STRONG RAINSHOWERS AND THUNDERSTORMS ARE TO THE SOUTH OF 13N BETWEEN 75W IN COLOMBIA AND 85W IN THE SOUTHERN HALF OF NICARAGUA. LOCALLY HEAVY RAINFALL AND FLASH FLOODING ARE POSSIBLE IN CENTRAL AMERICA TO THE NORTH OF 15N AT LEAST DURING THE NEXT 24 HOURS OR SO. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH PASSES THROUGH 32N54W IN THE CENTRAL ATLANTIC OCEAN...TO 25N55W TO 18N60W NEAR THE NORTHEASTERN CORNER OF THE CARIBBEAN SEA. A SHEAR AXIS CONTINUES FROM 18N60W TO 20N70W. A TROUGH EXTENDS FROM 20N70W...PRACTICALLY ALONG THE NORTHERN COAST OF THE DOMINICAN REPUBLIC...TOWARD AN UPPER LEVEL CYCLONIC CIRCULATION CENTER THAT IS NEAR 16N79W. THIS CYCLONIC CENTER IS ABOUT 120 NM TO THE SOUTHWEST OF JAMAICA. AN UPPER LEVEL TROUGH EXTENDS FROM A 34N23W CYCLONIC CIRCULATION CENTER...TO 28N29W AND 24N32W. A SURFACE RIDGE PASSES THROUGH 34N48W TO 30N61W...TO A 1021 MB HIGH PRESSURE CENTER THAT IS NEAR 31N79W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT