000 AXNT20 KNHC 082353 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN JUL 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... A NEW TROPICAL WAVE IS INTRODUCED ALONG 37W BASED ON SATELLITE IMAGERY AND SSMI DERIVED PRECIPITABLE WATER. THIS IS A HIGH AMPLITUDE TROPICAL WAVE WITH SOME TURNING NEAR 11N. THE SAL VERTICAL SOUNDING SHOWED THE PASSAGE OF THE WAVE ON THE 4TH OF JULY. THIS TROPICAL WAVE WILL BE ADDED ON THE 00Z SURFACE MAP. THE TROPICAL WAVE THAT WAS PREVIOUSLY ALONG 40W/41W IS RELOCATED FURTHER W ALONG 51W BASED ON THE HOVMOLLER DIAGRAM THAT CLEARLY SHOWS THE WESTWARD PROPAGATION OF THE WAVE...AND LATEST SATELLITE IMAGERY THAT REVEALS AN INCREASE IN CONVECTIVE ACTIVITY ON EITHER SIDE OF THE WAVE AXIS. THE CAYENNE VERTICAL SOUNDING ALSO INDICATES THAT THE WAVE IS JUST OVER THE AREA. CONVECTION HAS FLARED UP OVER FRENCH GUIANA AND SURINAME. A TROPICAL WAVE IS ALONG 66W SOUTH OF 16N MOVING W 10-15 KT. THIS WAVE HAS LOST MUCH OF ITS IDENTITY OVER THE LAST COUPLE OF DAYS...AND NOW IS MAINLY JUST A SURGE OF MOISTURE AS DEPICTED WELL BY SSMI DERIVED PRECIPITABLE WATER. DEEP CONVECTION REMAINS MINIMAL ON BOTH SIDES OF THE AXIS. A TROPICAL WAVE IN THE CARIBBEAN IS ALONG 82W/83W MOVING W NEAR 15 KT. THE WAVE...COUPLE WITH THE EPAC ITCZ IS GENERATING SCATTERED MODERATE CONVECTION OVER THE SW CARIBBEAN AND CENTRAL AMERICA S OF 13N. A DIFFLUENT PATTERN ALOFT IS ALSO ENHANCING THIS CONVECTIVE ACTIVITY. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 8N12W 5N25W 6N38W 9N50W 7N60W. CLUSTERS OF MODERATE CONVECTION ARE FROM 7N-12N BETWEEN 49W-56W MAINLY ASSOCIATED WITH THE TROPICAL WAVE ALONG 51W. WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 80NM N OF THE AXIS BETWEEN 22W-32W...AND WITHIN 100 NM SOUTH OF THE AXIS BETWEEN 40W-45W. ...DISCUSSION... GULF OF MEXICO... A SFC TROUGH REMAINS OVER THE SE PORTION OF THE GULF EXTENDING FROM THE WEST COAST OF FLORIDA NEAR 27N82W TO 24N86W. THE TROUGH IS STILL GENERATING SCATTERED SHOWERS OVER THE AREA...INCLUDING THE FLORIDA PENINSULA. THIS ACTIVITY ALSO AIDED BY UPPER DIFFLUENCE ASSOCIATED WITH AN UPPER HIGH LOCATED OVER CENTRAL FLORIDA. A WEAK 1016 MB HIGH ALSO REMAINS OVER THE NORTH-CENTRAL GULF WATERS NEAR 28N88W. THIS FEATURE IS EXPECTED TO DISSIPATE AS THE ATLC RIDGE BUILDS WWD BEGINNING TONIGHT. AN UPPER LOW IS SPINNING OVER CENTRAL MEXICO NEAR 20N100W SUPPORTING SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE SW PORTION OF THE GULF. FAIR WEATHER AND LIGHT TO MODERATE WINDS AROUND RIDGING DOMINATE THE REMAINDER OF THE REGION. CARIBBEAN SEA... ONCE AGAIN...THE MOST ACTIVE WEATHER ACROSS THE BASIN IS FOUND OVER THE SW CARIBBEAN AND SOUTHERN CENTRAL AMERICA DUE TO THE PRESENCE OF A TROPICAL WAVE AND THE EPAC ITCZ. SEE ABOVE. A SEMI-PERMANENT LOW PRES OVER COLOMBIA IS PRODUCING CLUSTERS OF MODERATE TO ISOLATED STRONG CONVECTION OVER WESTERN VENEZUELA AND NORTHERN COLOMBIA. WV IMAGERY SHOWS A BAND OF HIGH CLOUDS ASSOCIATED WITH UPPER WLY WINDS OVER THE SOUTHERN CARIBBEAN SOUTH OF 14N AND E OF NICARAGUA. DIFFLUENCE BETWEEN THE UPPER HIGH OVER FLORIDA AND AN UPPER LOW THAT PERSISTS JUST SOUTH OF JAMAICA IS ENHANCING SCATTERED SHOWERS AND TSTMS OVER CUBA AND JAMAICA. MODERATE TO FRESH TRADES ARE IN PLACE S OF THE ATLC SFC RIDGE...AND EXPECTED TO PERSIST THROUGH MIDWEEK. THE TRADES ARE ALLOWING TYPICAL PATCHES OF LOW LEVEL MOISTURE WITH EMBEDDED ISOLATED SHOWERS TO PUSH W ACROSS THE AREA. ACCORDING TO THE SAHARAN AIR LAYER FROM CIMSS...A PATCH OF AFRICAN DUST IS REACHING THE NE CARIBBEAN...INCLUDING PUERTO RICO AND THE VIRGIN ISLANDS BRINGING A MORE DRY AND STABLE ATMOSPHERE. ATLANTIC OCEAN... AN AREA OF SCATTERED SHOWERS/TSTMS REMAINS OFF THE FLORIDA COAST...WITHIN 120NM EITHER SIDE OF A LINE FROM PALM BEACH TO 31N70W. THE ACTIVITY IS BEING SUPPORTED BY UPPER DIFFLUENCE AROUND AN UPPER RIDGE AXIS. THE REMAINDER OF THE DISCUSSION AREA IS DOMINATED BY THE BERMUDA-AZORES HIGH ANCHORED ON A 1032 MB HIGH NEAR 42N20W. THIS IS PRODUCING ABUNDANT FAIR WEATHER AND LIGHT TO MODERATE TRADES E OF 70W. THE WEAK TROUGHING/LOW LEVEL CONFLUENCE OVER THE WRN ATLC WILL GRADUALLY DISSIPATE/LIFT NE OVER THE NEXT DAY OR SO AS THE ATLC RIDGE BUILDS W ACROSS FLORIDA AND INTO THE GULF. ELSEWHERE ALOFT ON THE LARGE SCALE...RIDGING CONTINUES TO DOMINATE THE FAR W AND E PORTIONS OF THE DISCUSSION AREA WITH BROAD TROUGHING OVER THE CENTRAL ATLC. OTHER SMALLER SCALE UPPER FEATURES ARE EMBEDDED IN THIS PATTERN BUT ARE NOT GENERATING SIGNIFICANT WEATHER. $$ GR