000 AXNT20 KNHC 201042 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI JUN 20 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 23W S OF 12N MOVING W 10-15 KT. THE WAVE SHOWS UP VERY WELL ON THE TPW PRODUCT AND THE HOVMOLLER DIAGRAM THAT CLEARLY INDICATES THE WWD PROPAGATION OF THE WAVE. LOW LEVEL SATELLITE DERIVED WINDS ALSO SUPPORTS THE POSITION OF THE WAVE AXIS WHICH EXHIBITS SOME CYCLONIC TURNING NEAR 7N. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS MAINLY AHEAD OF THE WAVE AXIS FROM 5N-11N BETWEEN 23W-27W. AN ACTIVE TROPICAL WAVE IS AFFECTING THE LESSER ANTILLES EARLY THIS MORNING WITH SCATTERED TO NUMEROUS SHOWERS...TSTMS AND GUSTY WINDS. ITS AXIS IS ALONG 61W/62W S OF 19N MOVING W 15-20 KT. A BROAD AREA OF CYCLONIC TURNING IS ASSOCIATED WITH THE WAVE. SURFACE OBSERVATIONS FROM THOSE ISLANDS REVEAL THAT THE WAVE HAS ENTERED THE E CARIBBEAN. SFC PRESSURES ARE FALLING TO NEAR 2 MB IN THIS AREA. THE MIMIC-TPW PRODUCT SHOWS THE WAVE VERY WELL WHERE A GOOD SURGE OF MOISTURE IS NOTED. THE WAVE IS EXPECTED TO AFFECT THE UK/US VIRGIN ISLANDS THIS MORNING AND PUERTO RICO THROUGHOUT THE DAY...BRINGING AN INCREASE IN SHOWER/TSTM ACTIVITY AND GUSTY WINDS. THE WAVE SHOULD REACH DOMINICAN REPUBLIC EARLY SATURDAY. ...ITCZ... THE ITCZ IS PRETTY ACTIVE EARLY THIS MORNING. ITS AXIS IS CENTERED ALONG 10N18W 6N26W 4N35W 3N45W INTO NRN BRAZIL NEAR 1N51W. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE FROM THE EQUATOR TO 5N BETWEEN 27W-40W. SIMILAR CONVECTION IS WITHIN 100 NM N OF AXIS AND WEST OF 40W TO THE SOUTH AMERICA COAST. ...DISCUSSION... GULF OF MEXICO... AN UPPER TROUGH IS OVER THE WESTERN HALF OF THE GULF EXTENDING FROM SE LOUISIANA TO THE BAY OF CAMPECHE. MODERATE TO STRONG SUBSIDENCE IS NOTED ALONG THE TROUGH AXIS. AN UPPER LEVEL RIDGE...ANCHORED ON A HIGH OVER CENTRAL AMERICA IS BUILDING OVER THE EASTERN HALF OF THE GULF REGION. A SWATH OF UPPER LEVEL MOISTURE IS BETWEEN THESE UPPER LEVEL FEATURES OVER THE YUCATAN PENINSULA AND THE SE GULF. AT THE SURFACE...A STATIONARY FRONT STRETCHES FROM SE LOUISIANA TO A 1013 MB LOW OVER S GEORGIA. A WEAK RIDGE DOMINATES THE REMAINDER OF THE AREA WITH MOSTLY FAIR WEATHER AND LIGHT WINDS. DIFFLUENCE ALOFT ON THE SE SIDE OF THE ABOVE MENTIONED UPPER TROUGH IS AIDING IN SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS THE EASTERN PORTION OF THE BAY OF CAMPECHE...THE YUCATAN PENINSULA AND THE SE GULF. CARIBBEAN... A RIDGE/TROUGH PATTERN IS OBSERVED OVER THE CARIBBEAN SEA. THE RIDGE COVERS THE WEST AND CENTRAL CARIBBEAN WHILE AN UPPER-LEVEL TROUGH FROM THE E-CENTRAL ATLC HAS ITS BASE OVER THE FAR SE CARIBBEAN AND THE WINDWARD ISLANDS. THE TROPICAL WAVE OVER THE LESSER ANTILLES IS INTERACTING WITH THIS UPPER-LEVEL TROUGH. AS A RESULTS...CONVECTION HAS INCREASED ESPECIALLY NEAR THE NORTHERN END OF THE WAVE AXIS. UPPER DIFFLUENCE BETWEEN AN UPPER-LEVEL TROUGH OVER THE EASTERN SEABOARD AND THE RIDGE OVER THE CARIBBEAN IS PRODUCING A BAND OF MULTILAYERED CLOUDS WITH EMBEDDED SHOWERS EXTENDING FROM THE CENTRAL BAHAMAS NE OVER THE W ATLC. SOME SHOWER ACTIVITY IS ALSO NOTED OVER N CENTRAL AMERICA AND THE SW CARIBBEAN NEAR 10N80W...LIKELY DUE A DIFFLUENT PATTERN ALOFT ASSOCIATED WITH THE AFOREMENTIONED UPPER-LEVEL RIDGE. AT THE SURFACE...THE ATLC RIDGE WILL BUILD SW OVER THE AREA AND STRENGTHEN THROUGH MON PRODUCING MODERATE TO FRESH TRADE WINDS ACROSS THE BASIN WITH THE STRONGEST WINDS UP TO 30 KT JUST OFFSHORE THE COLOMBIAN COAST. ATLANTIC... A BROAD UPPER TROUGH IS OVER THE EASTERN U.S. WHILE AN UPPER RIDGE EXTENDS FROM THE CARIBBEAN ALL THE WAY NE TO BEYOND 31N58W. THIS TROUGH SUPPORTS A FRONTAL BOUNDARY THAT CLIPS THE FAR NW PORTION OF THE AREA THEN CONTINUES NW TO A 1013 SFC LOW OVER S GEORGIA. AN UPPER LEVEL TROUGH EXTENDS OVER THE E-CENTRAL ATLC WITH THE BASE REACHING THE FAR SE CARIBBEAN AND THE WINDWARD ISLANDS. AN UPPER-LEVEL RIDGE DOMINATES MOST OF THE TROPICS AND IS ENHANCING CONVECTION ALONG THE ITCZ AXIS TODAY. HIGH PRES IS IN CONTROL OF THE FORECAST AREA EXTENDING A RIDGE WWD TO THE BAHAMAS AND CUBA. THIS SYSTEM IS FORECAST BY THE COMPUTER MODELS TO STRENGTHEN THROUGH MON PRODUCING A BELT OF MODERATE TO FRESH ELY WINDS ACROSS THE TROPICAL ATLC FROM THE AFRICAN COAST TO THE CENTRAL CARIBBEAN. $$ GR/CW