000 AXNT20 KNHC 211036 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT JUN 21 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... TROPICAL WAVE IS ALONG 32W S OF 11N MOVING W NEAR 20 KT. BROAD MID LEVEL INVERTED-V CURVATURE IS SHOWN ON SATELLITE IMAGERY AND THE MIMIC-TPW ANIMATION DEPICTS A MOISTURE SURGE BETWEEN 27W-33W. THE UPPER LEVEL FLOW IS KEEPING MOST OF THE CONVECTION TO THE W OF THE WAVE AXIS. CLUSTERS OF SCATTERED MODERATE/ ISOLATED STRONG CONVECTION ARE WITHIN 225W NM OF THE WAVE. TROPICAL WAVE IS IN THE CARIBBEAN ALONG 71W/72W S OF 20N MOVING W NEAR 20 KT. SATELLITE IMAGERY SHOWS A BROAD LOW LEVEL INVERTED-V CURVATURE WITH THE MIMIC-TPW ANIMATION DEPICTS A MOISTURE SURGE 72W TO THE LESSER ANTILLES. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 14N-17N BETWEEN THE WAVE AND 75W AND FROM 12N-18N BETWEEN THE WAVE AND 65W. BETWEEN 67W-73W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 10N12W 8N22W 8N30W 5N36W 2N52W. SCATTERED MODERATE/STRONG CONVECTION IS MOVING OFF THE COAST OF W AFRICA FROM 10N-14N E OF 19W AND FROM THE EQUATOR TO 8N BETWEEN 35W-41W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 225 NM N OF THE ITCZ BETWEEN 41W-52W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER RIDGE REMAINS ANCHORED OVER NW MEXICO COVERING THE FAR W GULF WITH AN UPPER LEVEL SHORTWAVE TROUGH EXTENDING FROM THE N GULF COAST NEAR MOBILE ALABAMA TO THE W BAY OF CAMPECHE. AN UPPER RIDGE ANCHORED IN THE W CARIBBEAN EXTENDS N OVER THE E GULF. MODERATE SUBSIDENCE ALONG THE UPPER TROUGH AXIS S OF 25N MAINTAINING MOSTLY CLEAR CONDITIONS IN THE SW GULF. UPPER LEVEL DIVERGENCE BETWEEN THIS TROUGH AND A RIDGE TO THE SOUTH IS GENERATING AN AREA OF SCATTERED SHOWERS/THUNDERSTORMS IN THE BAY OF CAMPECHE S OF 20N E OF 95W AND N OF THE YUCATAN FROM 22N-27N BETWEEN 85W-93W. SIMILAR ACTIVITY IS WITHIN 60 NM ALONG THE N GULF COAST FROM VERMILION BAY LOUISIANA TO S OF GALVESTON TEXAS. A WEAK PRESSURE PATTERN IS PROVIDING LIGHT WINDS ACROSS THE REGION. CARIBBEAN... AN UPPER RIDGE COVERS THE W CARIBBEAN ANCHORED IN THE E PACIFIC REGION OFF THE COAST OF EL SALVADOR AND EXTENDS N INTO THE GULF OF MEXICO. AN UPPER TROUGH FROM THE W/CENTRAL ATLC EXTENDS ACROSS THE GREATER ANTILLES NEAR THE MONA PASSAGE/E HISPANIOLA TO THE SW CARIBBEAN NEAR 12N77W. MODERATE/STRONG SUBSIDENCE BETWEEN THE UPPER TROUGH AND RIDGE IS KEEPING THE CENTRAL CARIBBEAN RELATIVELY CLOUD FREE WITH THE EXCEPTION THE ACTIVITY ASSOCIATED WITH THE TROPICAL WAVE. A TIGHTER PRESSURE GRADIENT BETWEEN THE SURFACE RIDGE OVER THE ATLC AND THE LOWER PRESSURE OVER SOUTH AMERICA IS PRODUCING MODERATE/STRONG EASTERLY TRADE WINDS ACROSS THE BASIN WITH THE STRONGEST WINDS UP TO 30 KT JUST OFF THE COLOMBIAN COAST. ATLANTIC... THE BROAD UPPER TROUGH IS OVER THE E US DIPS INTO THE W ATLC N OF 28N W OF BERMUDA WITH THE ASSOCIATED FRONTAL BOUNDARY NOT ENTERING THE REGION. AN UPPER LEVEL TROUGH EXTENDS FROM THE E/CENTRAL ATLC NEAR 32N36W SW TO A WEAK UPPER LOW NW OF LEEWARD ISLANDS NEAR 23N57W THROUGH THE MONA PASSAGE/E HISPANIOLA INTO THE CARIBBEAN. CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE IN THE VICINITY OF THE WEAK UPPER LOW COVERING THE AREA 21N-26N BETWEEN 55W-66W. THE LIMITING FACTOR IS THE RELATIVE DRY STABLE UPPER AIR ACROSS THE CENTRAL ATLC BETWEEN 30W-65W. AN UPPER HIGH IN THE E TROPICAL ATLC NEAR 10N27W IS KEEPING MOST OF THE CONVECTION THAT IS ASSOCIATED WITH THE TROPICAL WAVE W OF THE WAVE AXIS. THE ATLC IS DOMINATED BY A SURFACE RIDGE THAT COVERS THE ENTIRE BASIN INTO THE E GULF OF MEXICO AND ANCHORED BY A SERIES OF HIGHS N OF THE REGION. $$ WALLACE