000 AXNT20 KNHC 300600 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT JUL 30 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0545 UTC. ...SPECIAL FEATURES... TROPICAL STORM DON WAS DOWNGRADED TO A DEPRESSION AT 0300 UTC CENTERED INLAND OVER THE TEXAS COAST NEAR 27.2N 97.5W. THE ESTIMATED MINIMUM CENTRAL PRESSURE AT LANDFALL WAS 1006 MB. MAXIMUM SUSTAINED WIND SPEEDS ARE 30 KT WITH GUSTS TO 40 KT. MOST OF THE CONVECTION ASSOCIATED TO DON HAS MOVED INLAND WITH ONLY A FEW ISOLATED SHOWERS LINGERING ALONG THE IMMEDIATE COAST OF SOUTHERN TEXAS AND MEXICO S OF 27N. A TROPICAL WAVE IS MOVING ACROSS THE EASTERN TROPICAL ATLC ANALYZED FROM 19N49W TO A 1008 MB LOW CENTERED NEAR THE SOUTHERN EXTENT OF THE WAVE NEAR 11N45W. THIS WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP MOISTURE ON TPW PRODUCT. BROAD CYCLONIC FLOW IS OBSERVED IN THE LOW LEVEL CLOUD PATTERN ON SATELLITE IMAGERY. THIS WAVE WARRANTS WATCHING AS SOME MODELS FORECAST DEVELOPMENT WITH A THREAT TO THE LESSER ANTILLES AND PUERTO RICO. ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE 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 WEST-NORTHWESTWARD AT 15 TO 20 KT. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 8N-14N BETWEEN 37W-50W. THIS AREA OF CONVECTION IS ALSO RELATED TO THE ITCZ. ...TROPICAL WAVES... A TROPICAL WAVE IS W OF THE CAPE VERDE ISLANDS ANALYZED FROM 23N29W TO 13N30W MOVING W AT 15 KT. SATELLITE DATA SHOWS CYCLONIC TURNING ALONG THE WAVE AXIS N OF 18N. THIS WAVE IS LOCATED ALONG THE LEADING EDGE OF A LOW-MID MOISTURE SURGE DEPICTED ON TOTAL PRECIPITABLE WATER PRODUCT. HOWEVER...NO SIGNIFICANT CONVECTION IS NOTED WITH THE WAVE AT THIS TIME. A TROPICAL WAVE IS MOVING ACROSS THE WESTERN CARIBBEAN ANALYZED FROM 21N80W TO 12N82W MOVING W AT 15-20 KT. THE WAVE IS EMBEDDED WITHIN AN AREA OF DEEP MOISTURE ON TPW PRODUCT. BROAD LOW LEVEL CLOUD CYCLONIC CURVATURE IS OBSERVED ON SATELLITE DATA. THE WAVE IS JUST N OF THE MONSOON TROUGH LOCATED ON THE SW CARIBBEAN. THE COMBINATION OF THESE TWO SYSTEMS IS GENERATING A BROAD AREA OF SCATTERED HEAVY SHOWERS AND THUNDERSTORMS OVER A GREAT PORTION OF THE CENTRAL AND WESTERN CARIBBEAN W OF 72W. NO SIGNIFICANT DEVELOPMENT IS EXPECTED WITH THIS WAVE DUE TO INTERACTION WITH LAND. HOWEVER...LOCALLY HEAVY RAINFALL TO PORTIONS OF CENTRAL AMERICA ARE EXPECTED THROUGH THE WEEKEND AS THE SYSTEM TRACKS W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS GUINEA-BISSAU IN WEST AFRICA ...ENTERING THE ATLC ALONG 12N17W TO 11N22W. THE ITCZ CONTINUES FROM THIS POINT TO 13N29W...RESUMING W OF A TROPICAL WAVE NEAR 12N33W TO 10N40W...THEN RESUMES AGAIN S OF ANOTHER TROPICAL WAVE NEAR 9N45W TO THE COAST OF SURINAME IN SOUTH AMERICA NEAR 6N55W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 8N-14N BETWEEN 30W-50W. THIS AREA OF CONVECTION IS ALSO ASSOCIATED TO THE TROPICAL WAVE MOVING ACROSS THE EASTERN TROPICAL ATLC. ...DISCUSSION... GULF OF MEXICO... TROPICAL DEPRESSION DON IS NOW INLAND OVER SOUTHERN TEXAS. MOST OF THE CONVECTION ASSOCIATED TO DON HAS MOVED INLAND WITH ONLY A FEW ISOLATED SHOWERS LINGERING ALONG THE IMMEDIATE COAST OF SOUTHERN TEXAS AND MEXICO S OF 27N. THE REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF A VERY DRY AIRMASS ALOFT WITH STRONG SUBSIDENCE SUPPRESSING DEEP CONVECTION ACROSS THE AREA. JUST A SMALL CLUSTER OF SCATTERED SHOWERS REMAIN OVER THE BAY OF CAMPECHE S OF 21N E OF 95W. OTHERWISE...SURFACE RIDGING EXTENDS FROM NE TO SW ANCHORED BY A 1019 MB HIGH OVER THE SE CONUS. CARIBBEAN SEA... A TROPICAL WAVE MOVES ACROSS THE WESTERN CARIBBEAN. THIS SYSTEM ALONG WITH THE MONSOON TROUGH IN THE SW CARIBBEAN ARE GENERATING A BROAD AREA OF SCATTERED HEAVY SHOWERS AND THUNDERSTORMS OVER A GREAT PORTION OF THE CENTRAL AND WESTERN CARIBBEAN W OF 72W. THIS AREA OF PRECIPITATION AND MOISTURE IS EXPECTED TO SHIFT WESTWARD OVER THE NEXT 24 HOURS WITH THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AND POSSIBLE FLASH FLOODING ACROSS CENTRAL AMERICA LASTING THROUGH THE WEEKEND. THE REMAINDER OF THE CARIBBEAN BASIN IS EXPERIENCING FAIR WEATHER CONDITIONS WITH ISOLATED MODERATE TO HEAVY SHOWERS EMBEDDED IN THE MODERATE EASTERLY TRADE WINDS...ESPECIALLY OVER THE NE CARIBBEAN N OF 14N E OF 68W. ATLANTIC OCEAN... ASIDE THE TROPICAL WAVES MOVING ACROSS THE TROPICAL REGION...A STRONG HIGH PRESSURE SYSTEM DOMINATES THE DISCUSSION AREA THIS EVENING...ANCHORED WEST OF THE AZORES AND EXTENDING A RIDGE AXIS SW TO THE FLORIDA PENINSULA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA