000 AXNT20 KNHC 211225 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT AUG 21 2010 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1045 UTC. ...SPECIAL FEATURES... A 1009 MB ELONGATED LOW IS CENTERED OVER THE TROPICAL EASTERN ATLC NEAR 11N28W REMAINS THE FOCAL POINT OF A BROAD MONSOONAL TROUGH S OF 15N BETWEEN 28W-38W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION COVERS A BROAD AREA FROM 5N-16N BETWEEN 20W-40W. WHILE CONVECTION REMAINS GENERALLY UNORGANIZED...THE UPPER LEVEL ENVIRONMENT FOR TROPICAL CYCLONE DEVELOPMENT IS FAVORABLE FOR DEVELOPMENT AND A TROPICAL DEPRESSION COULD FORM DURING THE NEXT COUPLE OF DAYS. THERE IS A MEDIUM CHANCE OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT FEW DAYS AS IT MOVES SLOWLY WESTWARD. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 24N44W TO 11N42W MOVING W AT 10-15 KT. NIGHT VISIBLE SATELLITE IMAGERY INDICATES WEAK LOW-LEVEL CYCLONIC TURNING ALONG THE WAVE AXIS AND THIS WAS ALSO NOTED ON SATELLITE DERIVED WINDS. AN AREA OF MAXIMUM DEEP LAYER MOISTURE IS OBSERVED ON THE TPW IMAGERY EMBEDDED IN THE WAVE. HOWEVER... MUCH OF THIS MOISTURE IS POSITIONED BENEATH A STABLE SAHARAN AIR LAYER THAT COVERS MUCH OF THE CENTRAL AND E ATLC. THEREFORE...NO SIGNIFICANT DEEP ORGANIZED CONVECTION ACCOMPANIES THE WAVE... HOWEVER ISOLATED SHOWERS ARE WITHIN 20 NM WEST OF THE AXIS N OF 20N AND S OF 14N. A TROPICAL WAVE EXTENDS FROM 24N64W TO 16N66W MOVING WNW AT 10-15 KT. THE WAVE COINCIDES WITH A MID/UPPER LEVEL LOW CENTERED NEAR 25N68W. MODERATE TOTAL PRECIPITABLE WATER VALUES ACCOMPANY THIS SYSTEM N OF 17N...AS THIS MOISTURE CONTINUES TO ADVECT NORTHWARD DUE TO A WEAKNESS IN THE SUBTROPICAL RIDGE BETWEEN 60W-70W. NO DEEP CONVECTION IS OBSERVED AT THE MOMENT DUE TO THE LACK OF SUFFICIENT LOW-LEVEL MOISTURE. ONLY A FEW ISOLATED SHOWERS ARE NOTED WITHIN 30 NM IN THE VICINITY OF THE WAVE AXIS NORTH OF PUERTO RICO. TROPICAL WAVE IS OVER THE SW GULF OF MEXICO EXTENDING FROM 23N96W TO 13N92W MOVING W AT 5-10 KT. LOW-LEVEL CYCLONIC FLOW IS IN THE VICINITY OF THE WAVE...NOTED ON THE NIGHT VISIBLE SATELLITE IMAGERY. LOW-LEVEL SURFACE CONVERGENCE ALONG WITH PLENTY OF LOW-LEVEL MOISTURE IS GENERATING A LARGE AREA OF SCATTERED MODERATE AND ISOLATED STRONG CONVECTION OVER MUCH OF THE BAY OF CAMPECHE AND MEXICO COAST S OF 23N W OF 92W. ...ITCZ... THE ITCZ AXIS IS BETTER DEFINED NE OF S AMERICA CENTERED ALONG 11N44W 10N57W 12N70W. EMBEDDED WITHIN THE MONSOONAL TROUGH MENTIONED IN THE SPECIAL FEATURES SECTION...A 1011 MB LOW IS CENTERED NEAR 15N22W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 5N-16N BETWEEN 20W-40W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE COVERS MOST OF THE GULF OF MEXICO. WATER VAPOR IMAGERY SHOWS A MID/UPPER LEVEL DRY AIRMASS MOVING WESTWARD ACROSS MUCH OF THE BASIN TONIGHT...PROVIDING STABLE CONDITIONS ACROSS THE AREA. THIS UPPER LEVEL RIDGE SUPPORTS A 1016 MB HIGH CENTERED OVER THE NE BASIN NEAR 26N86W. HOWEVER...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS STILL REMAIN OVER THE FAR E AND SE GULF AFFECTING THE W COASTAL WATERS OF THE FLORIDA PENINSULA INCLUDING THE FLORIDA KEYS...FROM A WEAK SURFACE TROUGH PREVIOUSLY ALIGNED OVER THE W FLORIDA COASTLINE FROM 25N TO 30N. THE SW GULF IS UNDER THE INFLUENCE OF A TROPICAL WAVE ALONG 95W IMPACTING THE BAY OF CAMPECHE S OF 23N W OF 90W WITH SCATTERED SHOWERS AND TSTMS. CARIBBEAN SEA... ABUNDANT MOISTURE AND INSTABILITY IS NOTED ACROSS THE SW CARIBBEAN DUE TO CONVERGENCE IN THE VICINITY OF AN EXTENTION OF THE ITCZ ALONG 11N CROSSING FROM NORTHERN COLOMBIA TO CENTRAL NICARAGUA...GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS W OF 74W S OF 15N. FARTHER EAST...WATER VAPOR IMAGERY SHOWS A MID/UPPER LEVEL DRY AIRMASS ACROSS MUCH OF THE BASIN E OF 74W...PROVIDING STABLE CONDITIONS ACROSS THE AREA. HOWEVER...IN THIS REGION OF DRY AND STABLE AIR...A TROPICAL WAVE IS ANALYZED MOVING OVER PUERTO RICO ALONG 66W WITH NO ASSOCIATED DEEP CONVECTION DUE TO THE LACK OF LOW-LEVEL MOISTURE. ONLY A FEW ISOLATED SHOWERS ARE NOTED WITHIN 30 NM IN THE VICINITY OF THE WAVE AXIS NORTH OF PUERTO RICO. ATLANTIC OCEAN... UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE SE CONUS. WITH A FRONTAL BOUNDARY DRAPED NEAR THE NORTHERN EDGE OF THE DISCUSSION AREA ALONG 32N...WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING OVER THE W ATLC N OF 28N W OF W OF 73W. SE OF THE UPPER LEVEL ANTICYCLONE...AN MID/UPPER LEVEL LOW IS CENTERED NEAR 25N68W AND EXTENDS UPPER LEVEL TROUGHING TO 31N BETWEEN 60W-72W AND SOUTHWARD INTO THE NE CARIBBEAN SEA. A TROPICAL WAVE IS ALONG 66W WITH NO ASSOCIATED DEEP CONVECTION DUE TO THE LACK OF LOW-LEVEL MOISTURE. ONLY A FEW ISOLATED SHOWERS ARE NOTED WITHIN 30 NM IN THE VICINITY OF THE WAVE AXIS NORTH OF PUERTO RICO. ELSEWHERE ACROSS THE REMAINDER OF THE CENTRAL AND EASTERN ATLC...SURFACE RIDGING DOMINATES N OF 24N ANCHORED BY A 1023 MB HIGH CENTERED NEAR 34N22W MAINTAINING GENERALLY FAIR WEATHER. THE RIDGE AXIS EXTENDS FROM THE HIGH CENTER TO THE W ATLC NEAR 29N65W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA