000 AXNT20 KNHC 110601 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT MON AUG 11 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURES... A TROPICAL WAVE LOCATED OVER THE CENTRAL ATLANTIC ALONG 45W/46W OR ABOUT 780 NM EAST OF THE WINDWARD ISLANDS IS SUPPORTING AN AREA OF CONCENTRATED AND DISORGANIZED SCATTERED SHOWERS AND THUNDERSTORMS FROM 11N-16N BETWEEN 42W-49W. SATELLITE IMAGERY SHOWS SCATTERED MODERATE TO ISOLATED STRONG CONVECTION NORTH OF A 1009 MB LOW EMBEDDED ON THE WAVE AXIS NEAR 11N. THIS SYSTEM HAS THE POTENTIAL TO BECOME A TROPICAL DEPRESSION DURING THE NEXT COUPLE OF DAYS AS IT MOVES WESTWARD AT ABOUT 10 TO 15 KT. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 20W/21W S OF 17N MOVING W AT 10-15 KT. SOME CYCLONIC TURNING IS SEEN ALONG THE WAVE AXIS NEAR 12N WITH ISOLATED MODERATE SHOWERS FROM 7N-15N BETWEEN 18W-23W. A TROPICAL WAVE IS ALONG 66W/67W S OF 20N MOVING W 15-20 KT. THE WAVE CONTINUES TO SHOW A NARROW NORTH-SOUTH MOISTURE MAXIMUM ON SATELLITE IMAGERY. NO DEEP CONVECTION IS OBSERVED WITH SCATTERED SHOWERS WITHIN 90 NM ON EITHER SIDE OF THE WAVE AXIS...ACROSS PUERTO RICO ON THE NORTHERN END AND THE ABC ISLANDS ON THE SOUTHERN END. A SURGE OF AFRICAN DUST FOLLOWS THIS WAVE. A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN ALONG 76W S OF 21N MOVING W NEAR 15 KT. THE WAVE SHOWS AN INVERTED-V CLOUD SIGNATURE ON SATELLITE IMAGERY ACROSS THE CARIBBEAN SEA WATERS. THIS WAVE IS MOVING BENEATH A MIDDLE TO UPPER LEVEL LOW LOCATED OVER CENTRAL CUBA WHICH EXTENDS TROUGHING S-SW TO THE NICARAGUA AND HONDURAS BORDER. SCATTERED MODERATE CONVECTION IS ACROSS HAITI AND ERN CUBA AND MAY BE MORE RELATED TO THE UPPER TROUGHING THAN TO THE TROPICAL WAVE. ...THE ITCZ... THE ITCZ IS CENTERED ALONG 12N15W 12N17W 11N23W 12N42W 9N47W 7N59W. OUTSIDE OF THE CONVECTION ASSOCIATED WITH THE TWO TROPICAL WAVES...THERE IS SCATTERED MODERATE CONVECTION FROM 8N-12N BETWEEN 22W-29W. SIMILAR CONVECTION IS ALSO NOTED WITHIN 90 NM ON EITHER SIDE OF THE AXIS BETWEEN 31W-37W. ...DISCUSSION... GULF OF MEXICO... AN UPPER-LEVEL HIGH CENTERED OVER THE BIG BEND REGION OF TEXAS EXTENDS RIDGING OVER THE GULF WATERS NORTH OF 22N. AN UPPER LEVEL TROUGH LIES SOUTH OF THE RIDGE AND EXTENDS FROM THE W ATLC THROUGH THE STRAITS OF FLORIDA INTO THE GULF REGION ALONG 20N TO THE MEXICO COASTLINE NEAR 20N97W. THIS TROUGH SUPPORTS A DISSIPATING STATIONARY FRONT WHICH CROSSES CENTRAL FLORIDA THEN CONTINUES NW TO SE LOUISIANA. ISOLATED SHOWERS ARE SOUTH OF THE FRONTAL BOUNDARY AFFECTING THE ERN GULF FROM 25N-27N E OF 88W TO THE FLORIDA PENINSULA. AT THE SURFACE...A RIDGE ANCHORED ON A 1017 MB HIGH OVER WRN CUBA INFLUENCES THE REMAINDER OF THE GULF. THE SURFACE CIRCULATION AROUND THIS HIGH IS PROVIDING THE WRN AND CENTRAL GULF WITH LIGHT SOUTHERLY RETURN FLOW. THESE WINDS ARE EXPECTED TO INCREASE THROUGH TUE AS A LOW PRESSURE SYSTEM DEVELOPS OVER TEXAS AND NE MEXICO. CARIBBEAN SEA... AN UPPER-LEVEL LOW HAS BEEN MEANDERING OVER CUBA DURING THE LAST FEW DAYS ENHANCING SCATTERED SHOWERS ACROSS CUBA AND WRN HISPANIOLA. THE CYCLONIC FLOW COVERS THE YUCATAN PENINSULA AND NW CARIBBEAN EXTENDING EWD OVER HISPANIOLA. UPPER DIFFLUENCE BETWEEN THIS LOW AND A RIDGE CENTERED NEAR 12N76W WHICH COVERS MUCH OF THE SRN CARIBBEAN BASIN IS SUPPORTING SCATTERED MODERATE TO STRONG CONVECTION OVER THE SW CARIBBEAN FROM 8N-14N BETWEEN 74W-83W. MODERATE TO STRONG SUBSIDENCE AND DRY AIR IS IN CONTROL ACROSS THE ERN AND CENTRAL CARIBBEAN SEA E OF 73W. MODERATE TO STRONG EASTERLY TRADE WINDS ARE BLOWING ACROSS THE BASIN WITH THE STRONGEST WINDS OFFSHORE OF THE NRN COLOMBIAN COAST. TWO TROPICAL WAVES ARE MOVING WWD ACROSS THE BASIN...SEE TROPICAL WAVE SECTION FOR MORE DETAILS. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH IS LOCATED OVER THE ERN U.S. INTO THE FAR W ATLC WITH THE ASSOCIATED STATIONARY FRONTAL BOUNDARY ENTERING THE AREA NEAR 31N70W EXTENDING TO CENTRAL FLORIDA AND INTO THE GULF OF MEXICO. AN UPPER RIDGE IS TO THE SE CENTERED NEAR 29N66W. UPPER DIFFLUENCE BETWEEN THIS HIGH THE UPPER-LEVEL LOW SPINNING OVER ERN CUBA IS HELPING TO GENERATE SCATTERED SHOWERS AND TSTMS FROM 26N-32N BETWEEN 53W-69W. ELSEWHERE AN UPPER LOW IS OVER THE CENTRAL ATLC NEAR 27N51W WITH ANOTHER WEAK UPPER-LEVEL LOW OVER THE ERN ATLC NEAR 24N35W. AN UPPER-LEVEL HIGH IS LOCATED NEAR 23N21W EXTENDING A RIDGE ACROSS THE DEEP TROPICS. THIS UPPER SYSTEM IS ENHANCING CONVECTION ALONG THE ITCZ. OTHERWISE...THE ATLANTIC FORECAST AREA IS DOMINATED BY A 1026 MB SURFACE HIGH CENTERED NEAR 34N45W. THIS HIGH EXTENDS A RIDGE TO THE BAHAMAS AND WILL REMAIN NEARLY STATIONARY DURING THE NEXT 24 HOURS OR SO. $$ HUFFMAN