000 AXNT20 KNHC 142345 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED MAY 14 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 IS ADDED ON THE 18Z SFC MAP ALONG 17W/18W SOUTH OF 12N BASED ON SFC OBSERVATIONS...SATELLITE PHOTOS AND AN ASCAT PASS. A LARGE AREA OF SHOWERS WITH EMBEDDED TSTMS IS ASSOCIATED WITH THE WAVE...BUT MOST OF THIS ACTIVITY IS JUST AHEAD OF THE WAVE AXIS. IN ADDITION...THE MIMIC-TPW PRODUCT FROM CIMSS SHOWS THE PRESENCE OF THIS SYSTEM WITH A BULGE OF MOISTURE EXTENDING NWD TO AROUND 12N. ALSO...THE HOVMOLLER DIAGRAM INDICATES THE WWD PROPAGATION OF THIS WAVE THAT PROBABLY MOVED OUT OF AFRICA THIS MORNING. A WEAK TROPICAL WAVE IS ALONG 63W S OF 12N MOVING W NEAR 10 KT. THE WAVE IS VERY ILL-DEFINED AND MOSTLY INLAND OVER EASTERN VENEZUELA WHERE IT IS GENERATING SCATTERED MODERATE CONVECTION. SFC OBSERVATIONS OVER NE VENEZUELA AND THE SRN WINDWARD ISLANDS INDICATE SOME WIND SHIFT RELATED TO THE WAVE. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 4N10W 3N20W 2N40W 6N50W 6N58W. BESIDES FOR THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVE... WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 180-200 NM N OF AXIS AND W OF 37W. CLUSTERS OF MODERATE TO STRONG CONVECTION ARE OVER SW AFRICA. ...DISCUSSION... GULF OF MEXICO... THE GULF REGION LIES BETWEEN A 1022 MB HIGH JUST OFFSHORE THE CAROLINAS AND LOW PRES TROUGHING OVER S TEXAS AND EASTERN MEXICO. THIS WEATHER PATTERN IS PRODUCING FAIRLY UNIFORM 15-20 KT SE WINDS ACROSS THE AREA. FRAGMENTS OF MAINLY LOW-LEVEL CLOUDS ARE SEEN OVER THE GULF. ALOFT...A LARGE UPPER HIGH CENTERED OVER THE YUCATAN PENINSULA EXTENDS A RIDGE ACROSS THE ENTIRE GULF WITH ITS ASSOCIATED FLOW TRANSPORTING ABUNDANT UPPER LEVEL MOISTURE FROM THE EPAC THROUGH MEXICO INTO SE TEXAS AND MUCH OF THE GULF. DOPPLER RADAR REVEALS A LARGE AREA OF SHOWERS AND TSTMS OVER PARTS OF LOUISIANA AND MISSISSIPPI. A DIFFLUENT PATTERN ALOFT BETWEEN THE AFOREMENTIONED UPPER LEVEL RIDGE AND AN UPPER-LEVEL LOW SPINNING OVER NORTHERN TEXAS IS HELPING TO INDUCE THIS CONVECTIVE ACTIVITY. THE NEXT COLD FRONT IS FORECAST BY THE COMPUTER MODELS TO MOVE OFF THE TEXAS COAST THURSDAY NIGHT. CARIBBEAN SEA... THE TAIL END OF A COLD FRONT FROM THE ATLC IS PRODUCING SOME SHOWER ACTIVITY OVER EASTERN CUBA AND THE WINDWARD PASSAGE. SCATTERED SHOWERS HAVE ALSO DEVELOPED OVER HISPANIOLA AHEAD OF THE FRONT. OTHERWISE...VERY TRANQUIL WEATHER PREVAILS ACROSS THE BASIN COURTESY OF A LARGE MID-UPPER RIDGE CENTERED OVER THE YUCATAN PENINSULA AND UPPER TROUGHING OVER THE E CARIB. THESE UPPER FEATURES ARE PRODUCING MODERATE TO STRONG SUBSIDENCE ACROSS THE CARIBBEAN SEA SUPPRESSING THE DEVELOPMENT OF ANY SIGNIFICANT CONVECTION. HOWEVER...DUE TO UPPER DIFFLUENCE AND THE CLOSE PROXIMITY OF THE EPAC ITCZ...A COUPLE OF CLUSTERS OF MODERATE TO ISOLATED STRONG CONVECTION HAVE DEVELOPED NEAR THE COLOMBIA/PANAMA BORDER AND OVER WESTERN PANAMA. MODERATE TRADE WINDS OF 15-20 KT ARE BLOWING ACROSS THE REGION. THE GFS MODEL KEEPS MOISTURE FROM THE TAIL END OF THE FRONT AFFECTING HISPANIOLA ON THU. ATLANTIC OCEAN... A LARGE 995 MB LOW PRES SYSTEM IS WELL N OF THE AREA OVER THE W ATLC. THE ASSOCIATED COLD FRONT ENTERS THE FORECAST AREA NEAR 31N56W THEN CONTINUES SW CROSSING JUST E OF THE TURKS AND CAICOS AND INTO THE WINDWARD PASSAGE AND EASTERN CUBA. LOW-LEVEL CONVERGENCE ALONG THE FRONTAL BOUNDARY COUPLED WITH UPPER DIFFLUENT FLOW IS PRODUCING A 120-140 NM WIDE BAND OF SCATTERED SHOWERS AND TSTMS JUST AHEAD OF THE FRONT. A POST-FRONTAL TROUGH EXTENDS FROM THE LOW NEAR 40N58W TO 26N73W. COLD AIR STRATOCUMULUS CLOUDS NOTICED BEHIND THE FRONT IMPLY THAT A COOL AND DRIER AIR MASS HAS INVADE THE W ATLC AND THE BAHAMAS. THE REST OF THE CENTRAL AND THE E ATLC IS DOMINATED BY A 1024 MB HIGH LOCATED NEAR 31N37W. IN THE UPPER LEVELS...A TROUGH/RIDGE/TROUGH PATTERN DOMINATES DISCUSSION AREA WITH AN ELONGATED RIDGE OVER THE DEEP TROPICS ENHANCING CONVECTION ALONG THE ITCZ AND AHEAD OF THE TROPICAL WAVE. OF NOTE...MAY 15 MARKS THE BEGINNING OF THE EASTERN PACIFIC HURRICANE SEASON. BASED ON LATEST AVERAGES...EVERY YEAR 15 NAMED STORM FORM...9 OF WHICH BECOME HURRICANES AND 4 OF THOSE HURRICANES WOULD BE OF CATEGORY 3 OR GREATER IN STRENGTH ON THE SAFFIR-SIMPSON SCALE. THE ATLANTIC HURRICANE SEASON BEGINS JUNE 1ST WITH BOTH ATLANTIC AND EASTERN PACIFIC TROPICAL SEASONS ENDING NOVEMBER 30TH. $$ GR