000 AXNT20 KNHC 092330 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU AUG 09 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 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...METEOROLOGICAL ANALYSIS... WEATHER OBSERVATIONS...AND RADAR. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ADDED TO THE SFC MAP ALONG 25W S OF 16N ESTIMATED TO BE MOVING W 10 KT. MET-9 SATELLITE HOVMOLLER DIAGRAMS WERE THE MAIN SOURCE USED TO TRACK THIS FEATURE BACK OVER AFRICA. A LONG-TERM SATELLITE LOOP SHOWED THE BREAKING OF THIS ONCE LARGER WAVE NEAR THE AFRICAN COAST A DAY OR TWO AGO. THE MORE CONVECTIVE PART...THE NRN BRANCH...WAS SWEPT NEWD BY A STRONG UPPER LOW/TROUGH. THE SRN PORTION APPEARED TO CONTINUE TRACKING W...WHICH IS THE FEATURE THAT WAS JUST ADDED TO THE ANALYSIS. CURRENTLY...THIS WEAK SYSTEM IS NEAR THE WRN EDGE OF A LARGE CYCLONIC GYRE OVER W AFRICA. WHILE LOW-LEVEL TURNING IS APPARENT ON SATELLITE IMAGERY NEAR THIS LOW AMPLITUDE WAVE...CONVECTION IS MINIMAL. TROPICAL WAVE IS ALONG 39W S OF 14N MOVING W 10 KT. THIS LOW AMPLITUDE WAVE REMAINS WEAK ONLY CAUSING A SLIGHT PERTURBATION IN THE ITCZ. LITTLE SHOWER ACTIVITY IS ASSOCIATED WITH THIS FEATURE. HIGHER AMPLITUDE TROPICAL WAVE IS ALONG 59W/60W MOVING W NEAR 15 KT. THIS WAVE HAS BEEN EASY TO TRACK SINCE EMERGING OFF THE AFRICAN COAST ABOUT A WEEK AGO. THE UW-CIMSS TPW PRODUCT DEPICTS THIS WAVE NICELY AS A NARROW SURGE OF MOISTURE. SIGNIFICANTLY DRIER AIR/DUST IS BEING ADVECTED W BEHIND IT. THIS WAVE HAS PICKED SOME DEEP MOISTURE TODAY DUE TO THE DIFFLUENT ZONE ALOFT ALONG AND E OF THE WAVE. SCATTERED SHOWERS AND TSTMS ARE WEAKENING WITHIN 120 NM EITHER SIDE OF THE AXIS. TROPICAL WAVE IS ALONG 70W S OF 19N MOVING W NEAR 15 KT. SCATTERED TO NUMEROUS SHOWERS AND TSTMS ARE SHEARED OFF TO THE E OF THE AXIS FROM 13N-16N BETWEEN 64W-69W. MORE ACTIVITY HAS DEEPENED FURTHER W...BUT THIS APPEARS MORE ASSOCIATED WITH A SFC TROUGH AND A LARGE UPPER DIFFLUENT ZONE. MORE ON THIS ACTIVE WEATHER IN THE CARIB DISCUSSION SECTION. TROPICAL WAVE IS ALONG 84W S OF 20N MOVING W 10-15 KT. THIS WAVE LIES UNDERNEATH AN UPPER LOW WHICH IS HELPING TO GENERATE SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 90 NM OF THE AXIS. LITTLE LOW-LEVEL TURNING OR WAVE-TYPE SIGNATURE IS EVIDENT. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 12N16W 12N26W 10N38W 8N47W 11N58W. THE AXIS REMAINS QUIET THIS EVENING WITH ONLY SCATTERED MODERATE CONVECTION WITHIN 150 NM S OF THE AXIS BETWEEN 50W-54W. STRONG CONVECTIVE BLOW-UP IS OVER AFRICA APPROACHING THE COAST ASSOCIATED WITH THE NEXT TROPICAL WAVE. DISCUSSION... GULF OF MEXICO... THE COMBINATION OF A STRONG UPPER HIGH OVER THE SRN U.S. AND AN UPPER LOW ABOVE THE NW CARIB IS PRODUCING STRONG UPPER ELY FLOW ACROSS THE GULF. SCATTERED TSTMS FIRED UP THIS AFTERNOON ACROSS THE FLORIDA PANHANDLE WITH SOME WEAKENING DEBRIS ACTIVITY OVER THE COASTAL WATERS. BESIDES FOR THAT...THE REGION REMAINS QUIET WITH ONLY PATCHES OF MID-HIGH LEVEL CLOUDS. AT THE SFC...THE PATTERN REMAINS WEAK WITH A QUASI-STATIONARY 1016 MB HIGH CENTER NEAR 28N93W. THIS WEAK PRES GRAD IS EXPECTED TO CONTINUE FOR A FEW MORE DAYS ALLOWING WINDS AND SEAS TO REMAIN LIGHT/LOW. MOISTURE IS EXPECTED TO INCREASE ACROSS THE SE PORTION OF THE REGION THIS WEEKEND AS THE SFC TROUGH IN THE ATLC/N CARIB PUSHES INTO THE REGION. CARIBBEAN SEA... SEVERAL LOW-LEVEL FEATURES ALONG WITH A LARGE AREA OF UPPER DIFFLUENCE IS PRODUCING A CONSIDERABLE AMOUNT OF MOISTURE OVER THE CARIB. THE DIFFLUENT UPPER PATTERN CONSISTS OF AN UPPER LOW APPROACHING THE YUCATAN PENINSULA...TWO UPPER HIGHS NEAR 16N78W AND 15N65W AND ANOTHER UPPER LOW TO THE N OF THE REGION JUST E OF THE BAHAMAS. WITHIN THIS MOIST ENVIRONMENT THERE ARE TWO AREAS WHERE CONVECTION IS FOCUSED. THE MOST PRONOUNCED IS THE N CENTRAL/W CARIB...INCLUDING JAMAICA AND ERN CUBA N OF 15N BETWEEN 74W-79W. THIS SCATTERED MODERATE CONVECTION IS BEING TRIGGERED BY A SFC TROUGH WHICH IS ANALYZED ACROSS THE CENTRAL BAHAMAS TO THE CENTRAL CARIB SEA ALONG 25N76W 21N78W 15N76W. SLIGHTLY WEAKER CONVECTION IS OVER THE ERN CARIB FROM 13N-16N BETWEEN 64W-69W. THIS ACTIVITY IS ASSOCIATED WITH A TROPICAL WAVE NEAR 70W...REFER TO THE SECTION ABOVE FOR MORE INFO. SCATTERED SHOWERS ARE POSSIBLE JUST ABOUT ANYWHERE ELSE IN THE BASIN DUE TO THE MOIST ENVIRONMENT IN PLACE. ATLANTIC OCEAN... THE NRN HALF OF A SFC TROUGH EXTENDS NNE FROM ERN CUBA ACROSS THE CENTRAL BAHAMAS ALONG 22N78W 26N76W 30N72W. THIS PART OF THE TROUGH AXIS IS QUITE A BIT QUIETER...IN TERMS OF CONVECTION...AS COMPARED TO THE PORTION IN THE CARIB. A MID-HIGH LEVEL CLOUD DECK COVERS MOST OF THE REGION BETWEEN 50W-75W ASSOCIATED WITH THIS TROUGH AND DIFFLUENCE ALOFT BETWEEN AN UPPER LOW NEAR 25N69W AND OTHER UPPER FEATURES BOTH TO THE N AND S OF THE REGION. THE UPPER PATTERN THEN FOLDS INTO A LARGE SCALE HIGHLY ELONGATED TROUGH EXTENDING SW ALONG 32N31W 24N51W 12N58W. RIDGING TAKES OVER E OF THERE STRETCHING W FROM AN ANTICYCLONE OVER AFRICA ALONG 23N4W 20N23W 15N46W. ABUNDANT DRY AIR ALOFT COVERS THE NE PORTION OF THE AREA ROUGHLY N OF 20N E OF 30W. ELSEWHERE AT THE SFC...THE MAIN FEATURE IS A 1027 MB HIGH CENTERED NEAR 37N36W. THIS HIGH IS PRODUCING LIGHT TO MODERATE TRADES ACROSS THE BULK OF THE ATLC DISCUSSION AREA. A QSCAT PASS NEAR 20Z SHOWS A SMALL AREA OF SLIGHTLY STRONGER WINDS NEAR THE COAST OF NW AFRICA...BUT THESE WINDS ARE MUCH WEAKER THAN THE PAST FEW DAYS. $$ CANGIALOSI