000 AXNT20 KNHC 201021 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SUN AUG 20 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...TROPICAL WAVES... TROPICAL WAVE OFF THE COAST OF W AFRICA IS ALONG 31W/32W S OF 19N WITH A 1012 MB LOW ALONG THE WAVE NEAR 9N MOVING W 15-20 KT. LOW IS EMBEDDED WITHIN THE ITCZ AXIS WITH AN INVERTED-V CURVATURE OBSERVED ON INFRARED SATELLITE IMAGERY. CONVECTION IS WITHIN THE ITCZ AXIS. TROPICAL WAVE IS ALONG 45W/46W S OF 20N MOVING W NEAR 10 KT. WELL DEFINED INVERTED-V CURVATURE IS OBSERVED ON INFRARED SATELLITE IMAGERY. CONVECTION IS WITHIN THE ITCZ AXIS. TROPICAL WAVE IN THE E CARIBBEAN IS ALONG 65W/66W S OF 20N MOVING W 10-15 KT. UPPER RIDGE IS ENHANCING SCATTERED MODERATE CONVECTION FROM 13N-15N BETWEEN 62W-64W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 12N15W 8N27W 9N52W 8N61W ACROSS THE N PORTION OF SOUTH AMERICA AND THE SW CARIBBEAN OVER COSTA RICA INTO THE E PACIFIC REGION. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 7N-11N E OF 16W TO THE COAST OF AFRICA AND WITHIN 120/150 NM OF LINE FROM 5N29W-10N36W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 6N-13N BETWEEN 24W-29W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 5N-11N BETWEEN 39W-60W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER RIDGE ANCHORED OVER E/CENTRAL TEXAS EXTENDS OVER THE N GULF N OF 24N W OF 89W. THE UPPER LOW IN THE W ATLC EXTENDS A TROUGH ACROSS FLORIDA TO THE UPPER LOW IN THE SW GULF CENTERED ALONG THE COAST OF MEXICO NEAR TAMPICO AND IS PROVIDING ENOUGH DIFFLUENCE OVER THE E GULF TO GENERATE CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER MOST OF THE GULF AND STRONG THUNDERSTORMS FROM 23N-27W E OF 86W ACROSS FLORIDA AND THROUGH THE FLORIDA STRAITS INTO THE W ATLC. CARIBBEAN SEA... BROAD UPPER LOW IN THE W CARIBBEAN IS CENTERED JUST W OF JAMAICA NEAR 18N81W COVERING THE AREA N OF 15N W OF 75W TO THE YUCATAN PENINSULA. THIS IS GENERATING ISOLATED SHOWERS N OF 19N FROM THE WINDWARD PASSAGE TO OVER THE YUCATAN CHANNEL. BROAD UPPER RIDGE EXTENDS ACROSS THE S CARIBBEAN FROM COSTA RICA/NICARAGUA ALONG 14N70W TO ACROSS THE LESSER ANTILLES NEAR 16N61W INTO THE W TROPICAL ATLC. THIS IS PROVIDING ENOUGH DIFFLUENCE OVER S AND E CARIBBEAN TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 16N W OF 67W WITH CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION FROM 11N-16N BETWEEN 77W-84W. MODERATE TRADEWINDS ARE ACROSS THE AREA. ATLANTIC OCEAN... THE UPPER LOW IN THE W ATLC IS CENTERED NEAR 28N78W EXTENDING A TROUGH W ACROSS FLORIDA INTO THE GULF OF MEXICO AND COVERING THE W ATLC N OF 21N W OF 72W WITH AN ASSOCIATED 1012 MB LOW INLAND OVER THE COAST OF GEORGIA. THE UPPER LOW IS GENERATING THE SCATTERED SHOWERS/THUNDERSTORMS FROM 22N-28N W OF 76W ACROSS FLORIDA INTO THE E GULF OF MEXICO. AN UPPER LOW IS SE OF BERMUDA NEAR 30N60W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 21N-30N BETWEEN 50W-65W. AN UPPER RIDGE IS BEING INDUCED BETWEEN THESE TWO UPPER LOWS. THE UPPER RIDGE EXTENDS FROM THE E CARIBBEAN ACROSS THE LESSER ANTILLES NEAR 16N61W INTO THE W TROPICAL ATLC TO NEAR 27N46W. THE REMAINDER OF THE ATLC IS MOSTLY DOMINATED BY AN UPPER HIGH CENTERED N OF THE CAPE VERDE ISLANDS NEAR 20N21W WITH A WEAK UPPER TROUGH EXTENDING S OVER THE CANARY ISLANDS TO INLAND OVER NW AFRICA. DRY AIR REMAINS IN PLACE OVER THE E ATLC SO NO SIGNIFICANT CLOUDS OR SHOWERS ARE ASSOCIATED WITH THESE FEATURES. A SURFACE RIDGE DOMINATES THE ATLC WITH THE SURFACE HIGHS N OF THE REGION. SIGNIFICANT AMOUNTS OF AFRICA DUST CONTINUE TO MOVE OFF THE COAST OF W AFRICA TO NEAR 45W. $$ WALLACE