000 AXNT20 KNHC 102356 CCA TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU AUG 10 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN SECTIONS OF SOUTH AMERICA...AND THE 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 2315 UTC. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 43W SOUTH OF 18N MOVING WEST 15-20 KT. THIS WAVE CONTINUES TO HAVE A WELL DEFINED STRUCTURE WITH AN INVERTED V-SHAPE AND A GOOD AMOUNT OF LOW-MID LEVEL CYCLONIC TURNING. DESPITE THE WELL-DEFINED STRUCTURE...THE WAVE IS EMBEDDED IN A VERY DRY ENVIRONMENT LIMITING ANY SIGNIFICANT CONVECTION FROM DEVELOPING. HOWEVER THERE ARE SCATTERED SHOWERS AND TSTMS NEAR THE ITCZ AXIS LIKELY ENHANCED BY THIS WAVE...DISCUSSED IN MORE DETAIL IN THE ITCZ SECTION. A TROPICAL WAVE IS IN THE EASTERN CARIBBEAN ALONG 65W S OF 20N MOVING W NEAR 20 KT. THIS WAVE SHOWED SOME SIGNS OF POSSIBLY DEVELOPING YESTERDAY EVENING WITH A CLEAR MID-LEVEL CIRCULATION FORMING ALONG OR JUST AHEAD OF THE WAVE AXIS. SINCE THEN...THE APPEARANCE OF THIS WAVE HAS DETEORIATED ON SATELLITE IMAGERY WITH LITTLE ORGANIZATION OF ITS SHOWER ACTIVITY. IN FACT...THE PRECIP CONTINUES TO BECOME INCREASINGLY MORE DISORGANIZED WITH ONLY ISOLATED TO SCATTERED SHOWERS FOUND WITHIN 350 NM EITHER SIDE OF THE WAVE AXIS. THE UPPER LEVEL ENVIRONMENT IS UNFAVORABLE WITH STRONG NLY WINDS AND WIDESPREAD DRY AIR ON THE W SIDE OF AN UPPER LOW N OF THE VIRGIN ISLANDS. A TROPICAL WAVE IS ALONG 95W MOVING W 15-20 KT. THIS WAVE HAS MOVED ALMOST ENTIRELY INTO THE E PACIFIC BASIN AND HAS BECOME ILL-DEFINED. ...THE ITCZ... ITCZ IS CENTERED ALONG 12N15W 11N30W 12N45W 10N54W 12N64W. THERE ARE NO ANY AREAS OF SIGNIFICANT CONVECTION NEAR THE AXIS THIS EVENING. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 300 NM TO THE S OF THE AXIS E OF 41W. SOME OF THIS ACTIVITY IS BECOMING A LITTLE MORE CONCENTRATED BETWEEN 31W-41W LIKELY ENHANCED BY THE TROPICAL WAVE ALONG 43W. SIMILAR ACTIVITY IS WITHIN 240 NM EITHER SIDE OF THE AXIS W OF 47W. ...DISCUSSION... THE GULF OF MEXICO... THE MAIN FEATURE IN THE GULF IS AN UPPER LEVEL LOW WHICH IS NOW CENTERED IN THE WRN GULF NEAR 26N94W. THIS LOW HAS BEEN TRACKING FAIRLY QUICKLY ACROSS THE REGION...NEAR 20 KT. SCATTERED SHOWERS AND ISOLATED TSTMS ARE SPIRALING AROUND THE LOW MAINLY ON THE W AND S SIDE OF THE CIRCULATION FROM 23N-30N W OF 93W. THERE ARE A FEW WEAK SHOWERS THAT HAVE DEVELOPED ON THE E SIDE OF THE CIRCULATION FROM 24N-26N BETWEEN 85W-87W. AS OF 2100 UTC...THE UPPER LOW APPEARS TO BE BUILDING TO THE SFC WITH A FEW BUOYS/SHIPS SHOWING SOME CYCLONIC WIND SHIFT IN THE AREA. THIS SFC REFLECTION IS ANALYZED AS A TROF WITH THE AXIS ALONG 94W FROM 24N-27N. THE REMAINDER OF THE EAST AND CENTRAL GULF IS DOMINATED BY UPPER LEVEL DRY STABLE AIR LIMITING ANY SHOWER ACTIVITY TO ISOLATED. AT THE SURFACE...HIGH PRES RIDGING FROM THE ATLC HAS BUILT ACROSS THE GULF OF MEXICO WITH A 1018 MB HIGH CENTER NEAR 28N85W. THIS PATTERN IS KEEPING WINDS RATHER LIGHT AND GENERALLY FROM THE S-SE. THE GREATEST CHANCE OF RAIN TOMORROW WILL CONTINUE TO BE IN THE FAR W GULF IN THE VICINITY OF THE UPPER LOW....WHICH SHOULD BE INLAND OVER TEXAS/MEXICO AT THIS TIME TOMORROW. FAIRLY DRY AIR WILL REMAIN ABOVE MUCH OF THE AREA ALLOWING MOSTLY FAIR WEATHER TO CONTINUE ON FRI. THE CARIBBEAN SEA... THE EASTERN CARIBBEAN TROPICAL WAVE THAT SHOWED SOME POTENTIAL FOR DEVELOPMENT YESTERDAY HAS GREATLY DIMINISHED TODAY. THIS WAVE BASICALLY CONSISTS OF ONLY DISORGANIZED SCATTERED SHOWERS WHICH LIE FROM 11N-19N BETWEEN 60W-70W. THIS SYSTEM WAS LIKELY HIGHLY SHEARED AND INTRUDED BY DRY AIR FROM AN UPPER LEVEL LOW TO THE N OF THE NRN LEEWARD ISLANDS CENTERED NEAR 21N63W. MORE CONVECTIVE WEATHER IS IN THE SW CARIBBEAN AND ACROSS CENTRAL AMERICA WHERE SCATTERED MODERATE CONVECTION LIES FROM 11N-18N BETWEEN 80W-86W. THIS ACTIVITY HAS BEEN SURGING WESTWARD OVER THE LAST COUPLE OF DAYS WITHIN EASTERLY FLOW AND IS NOW BEING ENHANCED BY UPPER DIFFLUENCE BETWEEN THE GULF OF MEXICO UPPER LOW AND AN UPPER HIGH CENTERED NEAR COSTA RICA. THE REMAINDER OF THE CARIBBEAN IS UNDER A BROAD ATLC UPPER TROUGH WITH MAINLY DRY AIR. IN THE LOWER LEVELS...15 TO 25 KT EASTERLY TRADE FLOW CONTINUES TO DOMINATE MUCH OF THE CARIBBEAN THIS EVENING...DUE TO THE INTERACTION BETWEEN THE ATLC HIGH NORTH OF THE AREA WITH THE COLOMBIAN LOW. THE STRONGEST WINDS ARE LOCATED BETWEEN THE COLOMBIAN/VENEZUELAN COASTS AND PUERTO RICO/HISPANIOLA DUE TO THE TIGHTER PRES GRADIENT AND PERHAPS SOME ENHANCEMENT BY THE APPROACHING TROPICAL WAVE. SOME MOISTURE ASSOCIATED WITH THE WAVE WILL SPREAD TOWARDS THE CENTRAL AND WRN CARIBBEAN FRI AND SAT. THE ATLANTIC OCEAN... THE ATLC OCEAN IS FAIRLY QUIET THIS EVENING WITH AN UPPER LEVEL RIDGE/TROUGH/RIDGE PATTERN ACROSS THE AREA. A LARGE UPPER LEVEL RIDGE IS WELL ESTABLISHED ACROSS THE U.S. EXTENDING INTO THE WRN ATLC OUT TO 73W. A STATIONARY FRONT LIES TO THE N OF THE DISCUSSION AREA ALONG 33N W OF 65W LEADING INTO A COLD FRONT FARTHER EAST EVENTUALLY WRAPPING INTO A HIGH LATITUDE LOW. THIS FRONTAL BOUNDARY IS GENERATING A LINE OF CLOUDINESS AND SCATTERED SHOWERS N OF 28N W OF 50W. SOME OF THE GLOBAL MODELS INDICATE THAT THIS FRONT WILL BE SINKING SWARD INTO THE DISCUSSION AREA THIS WEEKEND. A BROAD UPPER TROUGH COVERS A GOOD PORTION OF THE CENTRAL ATLC WITH THE AXIS EXTENDING FROM A WEAK UPPER LOW NEAR 32N44W SWWARD TO AN UPPER LOW N OF THE VIRGIN ISLANDS NEAR 20N63W. VERY LITTLE SHOWER ACTIVITY IS ASSOCIATED WITH THESE UPPER LOWS...IN FACT...FAIRLY DRY STABLE AIR IS WIDESPREAD UNDER THE TROUGH. THE REMAINDER OF THE ATLC IS DOMINATED BY AN UPPER RIDGE WITH THE HIGH CENTER NEAR 17N38W. WIDESPREAD DRY UPPER LEVEL AIR IS UNDER THE UPPER RIDGE LIMITING ANY SHOWER ACTIVITY TO VERY ISOLATED. AT THE SURFACE...A NARROW RIDGE IS THE THEME WITH THREE SMALL HIGH PRESSURE CENTERS ANALYZED AT 1021 MB NEAR 28N32W...1019 MB NEAR 25N54W AND 1019 MB NEAR 26N68W...WITH THE RIDGE AXIS EXTENDING W THROUGH CENTRAL FLORIDA. $$ CANGIALOSI