000 AXNT20 KNHC 242358 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT MAY 24 2008 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 NEW TROPICAL WAVE WILL BE ADDED TO THE 00Z SURFACE MAP ALONG 20W/21W SOUTH OF 11N BASED ON SATELLITE IMAGERY...WINDS AT LOW LEVELS AND 850 MB SATELLITE DERIVED VORTICITY. THIS AREA OF CLOUDINESS EMERGED FROM WEST AFRICA EARLY THIS MORNING...AND IS SHOWING SOME CYCLONIC TURNING. A BAND OF MODERATE TO ISOLATED STRONG CONVECTION IS AHEAD OF THE WAVE AXIS ALONG 6N24W 4N25W 2N24W. MORE SHOWER ACTIVITY IS NEAR 2N20W. A TROPICAL WAVE IS ALONG 32W S OF 14N MOVING W AT 10 KT ON THE 18Z SFC MAP. LOW-LEVEL TURNING ALONG WITH A WEAK INVERTED-V SIGNATURE IS APPARENT NEAR 35W ON LATEST VISIBLE SATELLITE IMAGERY FOR THE DAY. IN ADDITION...LOW LEVEL DERIVED WINDS AND MIMIC-TPW SHOW THAT THE WAVE IS PROBABLY NEAR 35W. THIS WAVE WILL BE RELOCATED FARTHER W ON THE 00Z SFC MAP. A TROPICAL WAVE IS OVER EASTERN VENEZUELA ALONG 63W S OF 13N MOVING W 10 KT. UPPER AIR TIME-SECTION ANALYSIS FROM TRINIDAD AND TOBAGO INDICATE THAT THE WAVE PASSED OVER THE ISLAND DURING THE LAST 18 HOURS. SFC OBS ALONG THE SOUTHERNMOST WINDWARD ISLANDS DEPICT THE WIND SHIFT ASSOCIATED WITH THE WAVE AXIS. CONVECTIVE ACTIVITY ASSOCIATED WITH THIS FEATURE IS MAINLY INLAND OVER VENEZUELA. A TROPICAL WAVE IS OVER HONDURAS AND NICARAGUA ALONG 86W/87W S OF 17N MOVING VERY SLOWLY WWD. THE WAVE IS DIFFICULT TO TRACK SOUTH OF 10N DUE TO A LARGE SWATH OF WESTERLY SURFACE WINDS OVER THE EPAC. A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS OVER NICARAGUA ALONG THE WAVE AXIS NEAR 13N86W. SIMILAR CONVECTION IS SEEN OVER N COSTA RICA. ..THE ITCZ... ITCZ AXIS IS CENTERED ALONG 9N13W 4N20W 4N30W 3N36W CROSSING THE EQUATOR AT 45W INTO NE BRAZIL. OUTSIDE OF THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...A LARGE CLUSTER OF MODERATE TO STRONG CONVECTION IS MOVING OFF THE AFRICAN COAST THROUGH LIBERIA. MODERATE TO ISOLATED STRONG CONVECTION IS NEAR 4N17W... AND OVER NE BRAZIL. ...DISCUSSION... GULF OF MEXICO... A WEAK 1015 MB HIGH NEAR 29N87W EXTENDS A RIDGE OVER THE GULF REGION PRODUCING LIGHT TO MODERATE SE WIND FLOW. A FRONTAL BOUNDARY IS EXPECTED TO MOVE ACROSS THE SE CONUS AND ENTER THE NE GULF LATE TONIGHT/EARLY SUN. WINDS IN THE FAR NE GULF WILL SHIFT N 15KT FOLLOWING THE FRONTAL PASSAGE. AN UPPER-LEVEL RIDGE ANCHORED ON AN UPPER HIGH NEAR MANZANILLO MEXICO DOMINATES THE WESTERN HALF OF THE GULF GIVING THE AREA MODERATE TO STRONG SUBSIDENCE AND MOSTLY CLEAR SKIES. A SHORT-WAVE TROUGH OVER THE SE CONUS DIGS INTO THE EASTERN PORTION OF THE GULF. CONVECTION HAS FLARED UP OVER PARTS OF GUATEMALA AND THE YUCATAN PENINSULA. LIGHTNING DATA REVEALS SCATTERED TO NUMEROUS TSTMS EMBEDDED IN THIS AREA. UPPER DIFFLUENCE IS HELPING TO INDUCE THIS STRONG CONVECTIVE ACTIVITY. CARIBBEAN SEA... LIGHT TO MODERATE EASTERLY TRADE WINDS CONTINUE TO DOMINATE THE WEATHER PATTERN IN THE CARIBBEAN SEA. WESTWARD MOVING LOW-TOPPED TRADE WIND SHOWERS ARE EVIDENT ON SATELLITE PHOTOS OVER THE EASTERN CARIBBEAN...MORE CONCENTRATED BETWEEN THE LEEWARD ISLANDS AND PUERTO RICO. ANOTHER PATCH OF LOW LEVEL MOISTURE IS OVER JAMAICA AND ADJACENT COASTAL WATERS. A DIFFLUENT PATTERN ALOFT RELATED TO AN UPPER LEVEL HIGH OVER JAMAICA IS SUPPORTING MODERATE CONVECTION BETWEEN CUBA...HAITI...AND JAMAICA. A BAND OF LOW-LEVEL CLOUDS AND POSSIBLE SHOWERS REMAIN IN THE SW CARIBBEAN FROM THE COAST OF COLOMBIA TO THE COAST OF NICARAGUA S OF 12N DUE TO LOW-LEVEL WIND SPEED CONVERGENCE. SIGNIFICANT DEEP CONVECTION IS LIMITED ACROSS THE BASIN DUE TO THE PRESENCE OF A VERY DRY AND STABLE AIR MASS AROUND THE PREVIOUSLY MENTIONED UPPER-LEVEL HIGH. ATLANTIC OCEAN... AN AREA OF NUMEROUS SHOWERS AND THUNDERSTORMS...AS INDICATED BY SATELLITE IMAGERY AND LIGHTNING DATA...IS OVER THE W ATLC AND THE NW BAHAMAS ASSOCIATED WITH A DEVELOPING LOW PRESSURE SYSTEM. AS OF 2100 UTC...A 1010 MB LOW IS ANALYZED NEAR 28N75W. A SFC TROUGH EXTENDS FROM THE SFC LOW MOSTLY WWD TO SOUTH-CENTRAL FLORIDA NEAR LAKE OKEECHOBEE. DOPPLER RADAR INDICATES SHOWERS AND TSTMS MOVING SE ALONG THE EAST COAST OF FLORIDA. A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT FOR ALL OF MAINLAND SOUTH FLORIDA UNTIL 9 PM EDT THIS EVENING. DAMAGING WINDS AND LARGE HAIL ARE STILL POSSIBLE WITH THE STRONGEST TSTMS. FREEPORT IN THE BAHAMAS REPORTED A GUST WIND OF 43 KT WITH A TSTM OVERHEAD. THE SFC LOW IS FORECAST TO JOIN THE FRONTAL BOUNDARY THAT WILL MOVE FROM THE SE CONUS ACROSS THE NE GULF AND THE STATE OF FLORIDA TONIGHT/EARLY SUN. THE COLD FRONT WILL MOVE ACROSS SOUTH FLORIDA SUNDAY AFTERNOON AND EVENING. THE REMAINDER OF THE ATLC DISCUSSION AREA IS RATHER TRANQUIL UNDER THE INFLUENCE OF A 1026 MB SFC HIGH LOCATED WEST OF THE AZORES. FAIR WEATHER CUMULUS CLOUDS CONTINUE TO FLOW ACROSS THE REGION AROUND THE PERIPHERY OF THE RIDGE. ALOFT...A SHORT-WAVE TROUGH IS OVER N-CENTRAL FLORIDA AND THE EASTERN GULF. UPPER DIFFLUENCE AHEAD OF THIS TROUGH IS ENHANCING CONVECTION OVER FLORIDA AND THE W ATLC. A CLOSED UPPER-LEVEL LOW IS NEAR 30N38W WITH AN UPPER TROUGH EXTENDING SOUTH ALONG 38W/39W. ISOLATED TO SCATTERED SHOWERS IS ASSOCIATED WITH THE UPPER-LOW. AN UPPER RIDGE DOMINATES THE REMAINDER OF THE E ATLC AND W AFRICA. OF NOTE...THE HURRICANE PREPAREDNESS WEEK THIS YEAR WILL BE HELD FROM MAY 25TH TO MAY 31ST. HURRICANES CAN PRODUCE TRAGIC LOSS OF LIFE AND DEVASTATING ECONOMIC DISRUPTION. WE CAN NOT LOWER OUR GUARD DURING THE TROPICAL SEASON THAT WILL BEGIN PRETTY SOON...JUNE FIRST. NOW IT IS TIME TO PREPARE. $$ GR