000 AXNT20 KNHC 161750 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON APR 16 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 8N10W 3N20W EQ35W 2S45W. CLUSTERS OF MODERATE/ISOLATED STRONG CONVECTION ARE ALONG THE COASTLINE OF SIERRA LEONE AND LIBERIA. WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 40-60 NM SOUTH OF THE AXIS BETWEEN 18W-20W AND 32W-36W. ...DISCUSSION... GULF OF MEXICO... A MUCH COLDER AND DRIER AIRMASS IS GRIPPING THE GULF AND THE STATE OF FLORIDA THANKS TO A 1025 MB HIGH PRES SYSTEM LOCATED OVER SE LOUISIANA. A FAIRLY TIGHT PRES GRADIENT BETWEEN THIS SFC HIGH AND A POWERFUL LOW PRESSURE OVER THE NORTHEAST UNITED STATES IS PRODUCING MODERATE TO STRONG NLY WINDS OVER THE E GULF AND THE FLORIDA PENINSULA. BROKEN COLD AIR STRATOCUMULUS CLOUDS COVERS MOST OF THE GULF. SOME LOW CLOUDS ARE POOLED AGAINST THE SIERRA MADRE MOUNTAINS SOUTH OF TAMPICO MEXICO. VIS IMAGERY SHOWS CLEAR SKIES OVER THE SE U.S. AND THE NE CORNER OF THE GULF. ALOFT...A RIDGE IS BUILDING OVER THE GULF WHILE A SHARP SHORTWAVE TROUGH IS OVER THE SW US AND N BAJA. THIS TROUGH WILL SUPPORT THE NEXT COLD FRONT THAT IS FORECAST TO MOVE OFF TEXAS COAST EARLY WED. A PLUME OF UPPER LEVEL MOISTURE ASSOCIATED WITH THE EPAC JETSTREAM EXTENDS NEWD ACROSS N MEXICO AND W TEXAS. WINDS AND SEAS WILL SUBSIDE OVER THE GULF DURING THE NEXT FEW DAYS AS HIGH PRES MOVES SLOWLY EWD. CARIBBEAN SEA... THE STRONG COLD FRONT THAT ENTERED THE NW CARIBBEAN YESTERDAY CONTINUES TO MOVES SEWD. AS OF 15Z...THE FRONT ENTERS THE FORECAST AREA NEAR 31N67W THEN CONTINUES SW ACROSS THE CENTRAL BAHAMAS AND E CUBA. HAVANA REPORTED GUSTY SOUTH WINDS UP TO 47 KT (87 KPH) AHEAD OF THE FRONT AND 31 KT (57 KPH) BEHIND THE FRONT. A WELL DEFINED BAND OF LOW/MID CLOUDS WITH EMBEDDED SHOWERS AND ISOLATED TSTMS IS ASSOCIATED WITH THE FRONT. TEMPERATURES TONIGHT WILL BE UNSEASONABLY COOL FOR THIS TIME OF YEAR OVER SOUTH FLORIDA AND PROBABLY OVER PARTS OF W-CENTRAL CUBA AS A TONGUE OF COLD AIR PUSHES SWD OVER THE STRAITS OF FLORIDA. THIS FRONT HAS ALSO BROUGHT MUCH COOLER AIR TO THE YUCATAN PENINSULA AND N CENTRAL AMERICA. THE REMAINDER OF THE BASIN CONTINUES UNDER THE INFLUENCE OF A STRONG UPPER HIGH CENTERED MIDWAY BETWEEN JAMAICA AND CABO GRACIAS A DIOS WITH ABUNDANT DRY AND STABLE AIR ALOFT. THE TRADES ARE LIGHT TO MODERATE ACROSS MUCH OF THE AREA DUE TO THE WEAK PRES GRADIENT. HOWEVER...BEHIND THE COLD FRONT NLY WINDS OF 20-25 KT ARE BLOWING ADVECTING IN THE COOLER AIRMASS. THE COLD FRONT IS EXPECTED TO PUSH E AND SLOWLY WEAKEN REACHING THE E TIP OF CUBA AND EASTERN HONDURAS THIS EVENING. A FAIR AMOUNT OF LOW-LEVEL MOISTURE WILL LIKELY LINGER IN THE VICINITY OF THE FRONT BRINGING SOME INCREASE IN SHOWER ACTIVITY OVER HISPANIOLA TOMORROW AND OVER PUERTO RICO TUESDAY NIGHT THROUGH WEDNESDAY. WESTERN ATLANTIC... THE AFOREMENTIONED STRONG COLD FRONT IS PRODUCING GALE FORCE WINDS AND HAZARDOUS MARINE CONDITIONS OVER THE W ATLC. EARLIER QUIKSCAT PASS SHOWED WINDS OF 25 TO 35 KT AHEAD AND BEHIND THE FRONT. THIS COLD FRONT IS ASSOCIATED WITH A STRONG LOW PRES SYSTEM THAT IS NOW BATTERING THE NE US WHERE SEVERAL WATCHES AND WARNINGS HAVE BEEN ISSUED. A DEEP LAYERED TROUGH OVER THE FAR WEST ATLC IS SUPPORTING THIS FRONTAL SYSTEM. THE MID/UPPER LEVEL RIDGE OVER THE CARIBBEAN EXTENDS NE INTO THE W-CENTRAL ATLC THROUGH PUERTO RICO AND THE VIRGIN ISLANDS. AT THE SURFACE...A 1018 MB HIGH IS NEAR 30N55W EXTENDING A RIDGE TO THE NE CARIBBEAN. A TROUGH/RIDGE PATTERN COVERS THE REMAINDER OF THE ATLC OCEAN. A COLD FRONT/SFC TROUGH ARE ASSOCIATED WITH THIS UPPER TROUGH. THE SFC TROUGH RUNS FROM 30N36W TO 20N53W. A NARROW LINE OF LOW CLOUDS IS RELATED TO THIS FEATURE. ANOTHER RIDGE DOMINATES THE E ATLC ANCHORED ON A 1019 MB HIGH LOCATED NEAR 30N26W. THIN HIGH CLOUDS EXTENDS FROM N SOUTH AMERICA ACROSS THE OCEAN AND ARE ASSOCIATED WITH STRONG WLY WINDS. $$ GR