000 AXNT20 KNHC 081805 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED AUG 08 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 33W S OF 14N MOVING W NEAR 10 KT. THIS WAVE REMAINS WEAK AND DIFFICULT TO LOCATE DUE TO MULTIPLE LOW LEVEL SWIRLS IN THE VICINITY EMBEDDED WITHIN THE MONSOON TROUGH/ITCZ. THUS...THE CURRENT POSN REMAINS MOSTLY AN EXTRAPOLATION OF PREVIOUS ANALYSES. ISOLATED SHOWERS/TSTMS ARE WITHIN 90 NM OF THE AXIS FROM 7N-10N. TROPICAL WAVE IS ALONG 50/51W MOVING W NEAR 15 KT. WAVE REMAINS LARGE AMPLITUDE WITH INVERTED V PATTERN STILL NOTED IN THE SURROUNDING LOW AND MID LEVEL CLOUDS. THE ASSOCIATED MOISTURE PLUME CONTINUES TO SHOW UP WELL IN THE UW-CIMSS TPW PRODUCT. REGARDLESS...DEEP CONVECTION REMAINS MINIMAL WITH ONLY ONE SMALL CLUSTER OF MODERATE CONVECTION NOTED NEAR 17N52W. TROPICAL WAVE IS ALONG 58/59W S OF 16N MOVING W NEAR 15 KT. A WEAK WAVE PASSAGE WAS NOTED IN THE CAYENNE FRENCH GIANNA RAOB DATA JUST BEFORE 1200 UTC YESTERDAY. SCATTERED MODERATE CONVECTION IS WITHIN 200 NM EITHER SIDE OF THE AXIS FROM 9N-14N...APPROACHING THE SRN WINDWARD ISLANDS AND TRINIDAD. TROPICAL WAVE IS ALONG 79/80W S OF 19N MOVING W NEAR 15 KT. EXACT WAVE POSN REMAINS DIFFICULT TO LOCATE WITH CONVENTIONAL SATELLITE IMAGERY. OVER THE LAST FEW HOURS LIGHTNING DATA HAS DEPICTED A FEW TSTMS S OF THE CAYMAN ISLANDS WITHIN 90 NM OF THE AXIS N OF 17N. THIS MORNINGS SFC ANALYSIS ALSO REVEALED SOME WEAK TROUGHING IN THE VICINITY. IN ADDITION...A MODEST SURGE IN MOISTURE IS NOTED IN THE UW-CIMSS TPW PRODUCT. HOWEVER...THE TROUGHING FURTHER E MOVING THROUGH HISPANIOLA AND THE E/CENTRAL CARIBBEAN IS A MORE SIGNIFICANT FEATURE AT THE MOMENT. THERE CONTINUES TO BE SOME DEBATE ON WHETHER OR NOT THIS FEATURE IS A TROPICAL WAVE BUT HAVE CONTINUED TO ANALYZE IT AS A TROUGH AT THE MOMENT...AS IT IS VERY BLURRY IF ONE CAN TRACE THIS FEATURE BACK TO AFRICA. MORE ON THIS FEATURE IS DISCUSSED IN THE CARIB SECTION BELOW. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 13N17W 11N31W 11N40W 14N48W 12N52W 11N58W. THE ATLC PORTION OF THE ITCZ IS VERY QUIET THIS AFTERNOON WITH ALMOST NO DEEP CONVECTION NOTED E OF 30W. THERE ARE A FEW MODERATE TO STRONG CLUSTERS THAT ARE INLAND OVER AFRICA THOUGH. ISOLATED MODERATE CONVECTION IS S OF THE AXIS FROM 2N-10N BETWEEN 41W-48W. DISCUSSION... GULF OF MEXICO... A 1017 MB SFC HIGH IS QUASI-STATIONARY S OF LOUISIANA NEAR 26N90W. THIS CONTINUES TO PRODUCE FAIRLY LIGHT WINDS/LOW SEAS FOR THE GULF WHICH IS GENERALLY EXPECTED TO PERSIST OVER THE NEXT COUPLE OF DAYS. THE ONLY NOTABLE WEATHER IS THE CLUSTER OF MODERATE CONVECTION JUST S OF LOUISIANA FROM 27N-29N BETWEEN 89W-92W. THE CLOUD TOPS OVER THIS ACTIVITY ARE STRETCHING TO THE WNW WITH UPPER ESE FLOW SW OF THE LARGE ANTICYCLONE OVER THE SE U.S. THIS FEATURE AND THE INVERTED TROUGHING OVER THE SW PORTION DOMINATE THE UPPER PATTERN ACROSS THE BASIN. CARIBBEAN SEA... THE MOST SIGNIFICANT FEATURE IN THE CARIBBEAN BASIN CONTINUES TO BE THE INVERTED TROUGHING ALONG 69/70W THAT EXTENDS N THROUGH HISPANIOLA AND INTO THE ATLC. THIS IS PRODUCING SCATTERED MODERATE/ISOLATED STRONG CONVECTION N OF 13N BETWEEN 65W-71W. THE GFS MODEL SPREADS THE ASSOCIATED MOISTURE W/NW THROUGH HISPANIOLA...ERN CUBA...THE SE BAHAMAS AND JAMAICA THROUGH THU NIGHT. THE MOISTURE IS THEN EXPECTED TO SPREAD THROUGH THE REST OF CUBA...THE WRN BAHAMAS...AND SOUTH FLORIDA FRI THRU SUN. ELSEWHERE AT THE SFC TRADES ARE LIGHT TO MODERATE DUE TO THE WEAKNESS IN THE PRES GRADIENT BROUGHT ABOUT BY THE TROPICAL WAVE AND INVERTED TROUGH MOVING THROUGH THE BASIN. WINDS ANTICIPATED TO BE A LITTLER STRONGER TO THE E OF THE TROUGH AXIS ALONG 70W. IN THE UPPER LEVELS AN UPPER LOW IS SPINNING JUST N OF CENTRAL CUBA NEAR 23N77W. AN ELONGATED UPPER HIGH IS NEAR THE ABC ISLANDS. DIFFLUENCE BETWEEN THESE FEATURES IS ALSO SUPPORTING THE ACTIVITY S OF THE DOMINICAN REPUBLIC AND PUERTO RICO. ATLANTIC OCEAN... A FEW SHOWERS AND TSTMS ARE JUST OFFSHORE SOUTH FLORIDA AND THE WRN BAHAMAS. OTHERWISE THE WRN ATLC W OF 71W IS PRETTY QUIET. THE CARIBBEAN INVERTED SFC TROUGH EXTENDS N OF THE DOMINICAN REPUBLIC ALONG 19N70W 27N68W. SCATTERED SHOWERS/ISOLATED TSTMS WITH THIS FEATURE ARE MAINLY S OF 28N BETWEEN 63W-71W. IN ADDITION TO THE SFC SUPPORT THIS CONVECTION IS BEING SUPPORTED BY AN ELONGATED UPPER TROUGH EXTENDING SW FROM 30N65W TO CENTRAL CUBA NEAR 22N80W. A FEW EMBEDDED UPPER LOWS ARE ALSO NOTED IN THIS AFTERNOONS WV IMAGERY. UPPER FLOW IS WIDELY DIFFLUENT IN THIS VICINITY BETWEEN THE FLOW AROUND THE UPPER TROUGH/LOWS AND A SHORTWAVE RIDGE EXTENDING NNE FROM PUERTO RICO. OTHER LESS SIGNIFICANT UPPER LOWS ARE NEAR 23N57W AND 32N45W. THE LATTER HAS A TROUGH EXTENDING S TO NEAR 14N. UPPER RIDGING GENERALLY DOMINATES THE REMAINDER OF THE UPPER PATTERN EXCEPT FOR A WELL DEFINED UPPER LOW NEAR MADEIRA ISLAND. SW FLOW AHEAD OF THIS SYSTEM IS SPREADING MOISTURE NE THROUGH NW AFRICA. THE REMAINDER OF THE SFC PATTERN IS DOMINATED BY A 1030 MB HIGH NEAR 38N35W. THIS IS PRODUCING WIDESPREAD FAIR WEATHER AND MODERATE TRADES N OF 15N E OF 45W. NE WINDS REMAIN A LITTLE STRONGER ALONG THE COAST OF NW AFRICA WHERE THE HIGH INTERACTS WITH THERMAL TROUGHING OVER AFRICA...BUT NOT AS STRONG AS IT HAS BEEN OVER THE LAST COUPLE OF DAYS. $$ WILLIS