000 AXNT20 KNHC 252346 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT AUG 25 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 ALONG 27W S OF 20N MOVING W 10-15 KT. SATELLITE PICTURES SHOW BROAD TURNING IN THE STRATOCUMULUS CLOUDS. WIDELY SCATTERED MODERATE CONVECTION IS FROM 10N-12N BETWEEN 22W-29W. TROPICAL WAVE IS ALONG 51W/52W S OF 16N MOVING W 10 KT. VIS SAT IMAGERY SHOWS A SWIRL OF LOW CLOUDS ALONG THE WAVE AXIS...BUT WITHIN THE ITCZ NEAR 11N52W. ISOLATED MODERATE CONVECTION IS ASSOCIATED WITH THIS FEATURE. THIS TROPICAL WAVE WILL MOVE INTO TROPICAL N ATLC TONIGHT. TROPICAL WAVE IS IN THE W CARIBBEAN ALONG 82W/83W S OF 18N MOVING W NEAR 15 KT. A CYCLONIC TURNING IS ON THE NORTHERN END OF THE WAVE NEAR THE CAYMAN ISLANDS WHERE THERE ARE SCATTERED SHOWERS AND TSTMS. THE WAVE IS ALSO GENERATING SCATTRED MODERATE CONVECTION OVER THE SW CARIBBEAN WEST OF 80W. HIGH AMPLITUDE TROPICAL WAVE IS ALONG 95W S OF 24N MOVING W 15 KT. A 1009 MB LOW IS ALONG THE WAVE AXIS NEAR 20N95W. THIS BROAD AREA OF LOW PRESSURE IS PRODUCING CLOUDINESS AND THUNDERSTORMS IN THE SOUTHWESTERN GULF OF MEXICO. THIS SYSTEM IS FORECAST TO MOVE WESTWARD AND INLAND OVER MEXICO ON SUNDAY WITH NO SIGNIFICANT DEVELOPMENT. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 11N15W 9N26W 10N35W 11N49W 9N60W. BESIDES FOR THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES... ISOLATED MODERATE CONVECTION IS WITHIN 50-70 NM OF AXIS BETWEEN 34W AND 44W. A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS APPROACHING THE WEST COAST OF AFRICA PROBABLY ASSOCIATED WITH THE NEXT TROPICAL WAVE. DISCUSSION... GULF OF MEXICO... A SFC TROUGH IS OVER SOUTH FLORIDA AND WESTERN CUBA PRODUCING SCATTERED TO NUMEROUS SHOWERS WITH EMBEDDED TSTMS OVER THE AREA. ASSOCIATED MOISTURE IS AIDED BY THE TROPICAL WAVE LOCATED OVER THE NW CARIBBEAN. A DIFFLUENT PATTERN ALOFT BETWEEN A COUPLE OF UPPER LOWS...ONE OVER THE CENTRAL GULF AND THE SECOND ONE OVER THE NORTHERN BAHAMAS IS ALSO ENHANCING THIS CONVECTIVE ACTIVITY. FREQUENT LIGHTNING AND LOCALLY HEAVY RAIN ARE POSSIBLE. A 1009 MB LOW ASSOCIATED WITH A TROPICAL WAVE IS PRODUCING CLOUDINESS AND THUNDERSTORMS IN THE SOUTHWESTERN GULF OF MEXICO. CONVECTION HAS FLARED UP OVER THE YUCATAN PENINSULA EARLY THIS EVENING. MERIDA REPORTED HEAVY TSRA WITH REDUCED VISIBILITY. UPPER DIFFLUENCE...RELATED TO AN UPPER HIGH LOCATED BETWEEN TAMPICO AND VERACRUZ IS ALSO SUPPORTING THIS CONVECTION. A PAIR OF 1014 MB SFC HIGHS ARE OVER THE NORTHERN GULF WATERS NEAR 29N84W AND 29N92W. THIS WEAK HIGH PRES RIDGE WILL REMAIN ALONG 30N THROUGH WED. CARIBBEAN SEA... A TROPICAL WAVE IS OVER THE CARIBBEAN SEA. SEE TROPICAL WAVE SECTION. FURTHER E...SCATTERED MODERATE CONVECTION IS NEAR LAKE MARACAIBO IN VENEZUELA AND OVER NORTHERN COLOMBIA. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OVER AND JUST SOUTH OF HISPANIOLA ASSOCIATED WITH AN UPPER LOW CENTERED NEAR 13N72W. AN UPPER RIDGE FROM THE ATLC EXTENDS WWD INTO THE EASTERN CARIBBEAN. ANOTHER UPPER LEVEL RIDGE ANCHORED ON HIGH OVER THE WESTERN GULF OF MEXICO DOMINATES THE WESTERN CARIBBEAN WITH SIGNIFICANT MOISTURE. TRADEWINDS ARE MOSTLY 10-15 KT THROUGHOUT THE SEA. ATLANTIC OCEAN... A SURFACE TROUGH IS OVER N FLORIDA AND THE COAST OF GEORGIA GENERATING SCATTERED MODERATE TO ISOLATED STRONG CONVECTION. A WEAK COLD FRONT IS OVER THE ATLANTIC FORECAST AREA AND PRETTY FAR SOUTH FOR THIS TIME OF THE YEAR. IT EXTENDS FROM A 1012 MB LOW LOCATED NEAR 27N52W ALONG 24N60W 29N69W. ISOLATED MODERATE CONVECTION IS WITHIN 60 NM OF THE FRONT. THIS FEATURE IS FORECAST TO DISSIPATE OVERNIGHT. A RIDGE AXIS IS OVER THE EASTERN ATLANTIC ALONG 32N27W 25N35W TO A 1016 MB HIGH NEAR 25N39W. FAIR WEATHER AND LIGHT WINDS DOMINATE THE AREA. ALOFT... A RIDGE/TROUGH/RIDGE PATTERN COVERS THE DISCUSSION AREA. A RIDGE IS OVER THE W ATLANTIC N OF 20N BETWEEN 65W-75W. A TUTT LOW IS NE OF PUERTO RICO NEAR 23N57W. AN UPPER TROUGH CONNECTS THIS LOW WITH THE OTHER ONE LOCATED SOUTH OF HISPANIOLA. A LARGE UPPER LEVEL HIGH IS CENTERED NEAR 22N40W AND DOMINATES THE REMAINDER OF THE OCEAN. VERY DRY AIR ALOFT RESULTING IN STRONG SUBSIDENCE IS SEEN N OF 18N AND WEST OF 5OW. $$ GR