000 AXNT20 KNHC 052353 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU JUL 05 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... A TROPICAL WAVE IS TILTED FROM 16N22W TO 4N30W MOVING W 10-15 KT. A LARGER SCALE INVERTED V-TYPE STRUCTURE IS APPARENT FURTHER TO THE NE...REACHING THE CAPE VERDE ISLANDS. MINIMAL SHOWER ACTIVITY IS ASSOCIATED WITH THIS WAVE THAT IS GENERATING SOME CLOUDINESS OVER THESE ISLANDS. AS OF 2100 UTC...A 1014 MB LOW PRES SYSTEM LOCATED NEAR 11N50W OR ABOUT 650 NM EAST OF THE SOUTHERN WINDWARD ISLANDS IS MOVING W AT 10-15 KT. THIS WEAK LOW CONTINUES TO HAVE MINIMAL TSTM ACTIVITY AND ENVIRONMENTAL CONDITIONS ARE BECOMING LESS FAVORABLE FOR DEVELOPMENT. THE LOW IS EMBEDDED IN A TROPICAL WAVE LOCATED ALONG 49W/50W. MOISTURE FROM THIS LOW/TROPICAL WAVE SHOULD AFFECT THE WINDWARD ISLANDS SAT. LATEST SATELLITE IMAGERY SHOWS A SLIGHTLY INCREASE IN TSTMS NEAR THE CENTER. A TROPICAL WAVE IS MOVING ACROSS THE E CARIBBEAN WITH THE AXIS ALONG 63W. THE WAVE IS PRODUCING SOME SHOWER ACTIVITY OVER THE WINDWARD ISLANDS AND NE VENEZUELA. TRINIDAD AND TOBAGO REPORTED MAINLY LIGHT TO MODERATE SHOWERS AND TSTMS WITH THE PASSAGE OF THE WAVE. SIMILAR ACTIVITY AND GUSTY WINDS AFFECTED THE NORTHERN LEEWARD ISLANDS. THIS WAVE WILL MOVE ACROSS THE VIRGIN ISLANDS AND PUERTO RICO TONIGHT REACHING DOMINICAN REPUBLIC TOMORROW MORNING WITH SOME INCREASE IN SHOWER ACTIVITY. A WIND SURGE WILL FOLLOW THE WAVE. THE SAN JUAN DOPPLER RADAR IS ALREADY SHOWING SCATTERED SHOWERS MOVING FROM E TO W ACROSS THE VIRGIN ISLANDS. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 8N13W 7N25W 4N36W 6N47W 8N60W. SCATTERED SHOWERS AND TSTMS ARE WITHIN 120 NM S OF THE AXIS BETWEEN 17W-22W. ...DISCUSSION... GULF OF MEXICO... A LINE OF SHOWERS WITH EMBEDDED TSTMS IS ACROSS THE NW CORNER OF THE GULF. SIMILAR ACTIVITY IS SEEN OVER THE N GULF WATERS AND NEAR THE W COAST OF FLORIDA. AN ILL-DEFINED SURFACE LOW PRESSURE AREA LOCATED OVER FLORIDA NEAR 29N82W IS PRODUCING A LARGE AREA OF DISORGANIZED SHOWERS AND THUNDERSTORMS ACROSS THE FLORIDA PENINSULA AND COASTAL WATERS. A WEAK TROUGH EXTENDS FROM THIS SFC LOW ACROSS THE FLORIDA PENINSULA AND THE SE PORTION OF THE GULF. UPPER DIFFLUENT ASSOCIATED WITH AN UPPER HIGH OVER THE NORTH-CENTRAL GULF IS SUPPORTING ALL THIS CONVECTIVE ACTIVITY. AN UPPER LOW IS SPINNING OVER MEXICO AND GUATEMALA BRINGING TROPICAL MOISTURE FROM THE SW CARIBBEAN INTO THE YUCATAN PENINSULA AND THE GULF. TIGHTENED PRES GRADIENT BETWEEN HIGH PRES OVER THE SE STATES AND LOWER PRES OVER TEXAS/MEXICO IS PRODUCING MODERATE SELY WINDS ACROSS THE SW GULF. WEAK HIGH PRES WILL MEANDER OVER THE CENTRAL WATERS THROUGH SUN. ACCORDING TO THE GFS MODEL...THE LOW OVER FLORIDA WILL WEAKEN TONIGHT BUT A TROUGH WILL PERSIST OVER THE AREA. CARIBBEAN SEA... DRY AIR ALOFT ADVECTED FROM THE TROPICAL ATLC DOMINATES A GOOD PORTION OF THE BASIN GIVING THE AREA MOSTLY FAIR WEATHER. THE THE EXCEPTION IS THE E CARIBBEAN WHERE THERE IS A TROPICAL WAVE MOVING WWD. SEE ABOVE. THE UPPER ATMOSPHERE IS MORE MOIST FURTHER W SUPPORTED BY AN UPPER LOW SPINNING OVER MEXICO AND GUATEMALA. CLUSTERS OF MODERATE CONVECTION ARE OVER COSTA RICA AND PANAMA DUE TO THE CLOSE PROXIMITY OF THE EPAC ITCZ. SCATTERED SHOWERS AND ISOLATED TSTMS ARE FOUND OVER NORTHERN CENTRAL AMERICA. AFTERNOON HEAT INDUCED SHOWERS AND TSTMS ARE OVER CUBA MODERATE TO STRONG ELY TRADE WINDS CONTINUES TO AFFECT THE AREA PARTICULARLY THE SOUTH-CENTRAL CARIBBEAN NEAR THE COAST OF COLOMBIA. THE ATLC RIDGE N OF REGION WILL MAINTAIN ELY TRADES THROUGH THE UPCOMING WEEKEND. ATLANTIC OCEAN... AN ILL-DEFINED SURFACE LOW PRESSURE AREA LOCATED OVER THE FLORIDA PENINSULA NEAR 29N82W IS PRODUCING A LARGE AREA OF DISORGANIZED SHOWERS AND THUNDERSTORMS. ENVIRONMENTAL CONDITIONS ACROSS THE AREA DO NOT SUPPORT TROPICAL CYCLONE DEVELOPMENT. HOWEVER...PERIODS OF LOCALLY HEAVY RAINFALL ARE POSSIBLE OVER PORTIONS OF FLORIDA AND THE BAHAMA ISLANDS OVER THE NEXT COUPLE OF DAYS. A WARM FRONT EXTENDS EWD FROM THIS LOW ALONG 30N77W 29N71W. A STATIONARY FRONT CLIPS THE AREA ALONG 30N BETWEEN 55W AND 65W. MODERATE CONVECTION IS SEEN BETWEEN THE WARM FRONT AND THE NW BAHAMAS AND ALONG THE E FLORIDA COAST. FARTHER E...THERE HAS BEEN LITTLE CHANGE OVER THE PAST FEW DAYS WITH RIDGING STILL DOMINATING BOTH AT THE SFC AND ALOFT. THE AZORES HIGH WITH 1029 MB CENTER IS ANALYZED NEAR 37N27W. THIS HIGH IS PRODUCING A LARGE AREA OF MODERATE TRADES ACROSS THE ATLC. STRONG NLY WINDS ARE NEAR THE AFRICAN COAST DUE TO THE TIGHTENING PRES GRADIENT BETWEEN THE HIGH AND INVERTED TROUGHING OVER THE CONTINENT. A SERIES OF UPPER HIGHS ARE PROVIDING A VERY STABLE AIRMASS ACROSS THE CENTRAL AND E ATLC WITH ONLY LOW-LEVEL STABLE STRATOCUMULUS CLOUDS SEEN ACROSS MUCH OF THE FORECAST REGION. $$ GR