000 AXNT20 KNHC 081740 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE APR 08 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ... THE ITCZ IS PRETTY ACTIVE E OF 20W. IT AXIS IS CENTERED ALONG 4N10W 2N20W...THEN ALONG THE EQUATOR BETWEEN 30W AND 40W INTO NE BRAZIL. A SFC TROUGH IS ANALYZED ON THE 12Z MAP ALONG 14/15W WHERE SATELLITE IMAGERY SHOWS AN AREA OF MODERATE TO STRONG CONVECTION. ANOTHER SFC TROUGH IS INTRODUCED ALONG 36W FROM 5N TO 10N. VIS SAT PHOTOS REVEAL A WELL DEFINED CYCLONIC TURNING ALONG THE TROUGH AXIS NEAR 8N. SCATTERED MODERATE CONVECTION IS WITHIN 200 NM E OF TROUGH AXIS. MOISTURE ASSOCIATED WITH THIS FEATURE IS FORECAST BY THE COMPUTER MODELS TO MOVE WWD REACHING 50W LATE FRIDAY OR SATURDAY. ...DISCUSSION... GULF OF MEXICO... A SHORT WAVE TROUGH MOVING EWD ACROSS THE EASTERN GULF EXTENDS FROM SOUTHERN GEORGIA/N FLORIDA SW TO THE YUCATAN PENINSULA. A SURFACE REFLECTION TROUGH LIES OVER THE NW CARIBBEAN AND THE GULF OF HONDURAS INTO CENTRAL HONDURAS. THE UPPER TROUGH IS STILL ENHANCING SOME SHOWER/TSTM ACTIVITY OVER THE SE PORTION OF THE GULF...SOUTH-CENTRAL FLORIDA AND THE KEYS INCLUDING ALSO PARTS OF WEST-CENTRAL CUBA WHERE LIGHTNING DATA REVEALS SCATTERED TSTMS. SINCE MIDNIGHT THE CITY OF HAVANA WAS REPORTING MAINLY LIGHT TO MODERATE SHOWERS AND TSTMS. A SECOND SURFACE TROUGH IS OVER SOUTH FLORIDA AND THE KEYS EXTENDING WNW INTO THE GULF NEAR 25N86W. THE SHORTWAVE TROUGH IS FORECAST TO MOVE E ACROSS THE STATE OF FLORIDA THIS AFTERNOON AND EVENING KEEPING THE RISK OF SHOWERS. BROAD UPPER RIDGE ANCHORED IN THE E PACIFIC REGION COVERS MEXICO AND INTO THE W GULF W OF 90W. STRONG SUBSIDENCE AND IMPLIED DRY STABLE AIR IS NOTED WITHIN THE RIDGE AXIS. A SFC RIDGE ALONG THE EASTERN SEABOARD GRIPS THE NE PORTION OF THE GULF. THIS WEATHER PATTERN IS PRODUCING LIGHT TO MODERATE E TO SE WINDS ACROSS MOST OF THE GULF. LOOKING AHEAD... RETURN SLY FLOW IS FORECAST TO INCREASE THU AHEAD OF THE NEXT COLD FRONT WHICH WILL MOVE OFF THE TEXAS AND LOUISIANA COASTS LATE FRIDAY...THEN MOVE INTO THE E GULF BY LATE SAT AND TO SE OF THE REGION SUN. MODERATE TO STRONG NLY WINDS WILL FOLLOW THE FRONT. CARIBBEAN SEA... UPPER SHORTWAVE TROUGH IN THE GULF OF MEXICO EXTENDS OVER THE NW CARIBBEAN W OF 84W GENERATING SCATTERED SHOWERS AND TSTMS OVER WEST-CENTRAL CUBA. DOPPLER RADAR INDICATES THAT THIS ACTIVITY HAS BEGUN TO MOVE OFFSHORE TOWARD THE STRAITS OF FLORIDA WHILE NEW CELLS ARE DEVELOPING OVER THE PROVINCE OF PINAR DEL RIO IN CUBA. BROAD MID TO UPPER RIDGE DOMINATES THE REMAINDER OF THE BASIN. SWLY FLOW ON THE WESTERN PERIPHERY OF THE RIDGE IS ADVECTING A PLUME OF UPPER LEVEL MOISTURE/HIGH CLOUDS FROM PANAMA ALL THE WAY NE CROSSING SOUTH OF HISPANIOLA. SOME SHOWER ACTIVITY IS SEEN NEAR COSTA RICA AND PANAMA DUE TO THE CLOSE PROXIMITY OF THE EPAC ITCZ. STREAMERS OR CLOUD LINES HAVE DEVELOPED ACROSS THE LESSER ANTILLES AND THE VIRGIN ISLANDS UNDER AN ESE WIND FLOW. ONE OF THEM EXTENDING FROM ST. CROIX REACHES SE PUERTO RICO. HIGH PRES N OF THE AREA WILL MAINTAIN LIGHT TO MODERATE E WINDS ACROSS THE EASTERN AND CENTRAL PART OF THE BASIN THROUGH THE NEXT FEW DAYS. THESE WINDS ARE USHERING IN PATCHES OF LOW CLOUDS WITH EMBEDDED MAINLY LIGHT SHOWERS. ATLANTIC OCEAN... A RIDGE/TROUGH/RIDGE PATTERN IS OBSERVED ACROSS THE DISCUSSION AREA. THE RIDGE AXIS EXTENDS NWD ALONG 65W CROSSING BERMUDA. A BROAD UPPER LEVEL TROUGH IS OVER THE E ATLC WHILE ANOTHER RIDGE DOMINATES WEST AFRICA AND THE IBERIAN PENINSULA. A JET STREAM BRANCH WITH CORE WINDS OF 90 TO 110 KT IS ALONG THE BASE OF THE UPPER TROUGH EXTENDING FROM 29N33W ALL THE WAY NE OVER PORTUGAL AND SPAIN. ANOTHER WIND MAXIMA UP TO 90 KT IS SEEN BETWEEN THE CANARY AND THE CAPE VERDE ISLANDS. BROAD E/W UPPER RIDGE COVERS THE TROPICAL BELT WITH AN UPPER LEVEL ANTICYCLONE NEAR 10N18W. AT THE SURFACE...FROM WEST TO EAST... A WEAK 1012 MB SFC LOW IS SPINNING OFF THE FLORIDA COAST NEAR 29N75W. THE LOW HAS A TROUGH EXTENDING SW ACROSS THE NW BAHAMAS AND THE FLORIDA KEYS. SCATTERED SHOWERS AND TSTMS ARE ASSOCIATED WITH THE TROUGH WHILE A SWIRL OF LOW CLOUDS WITH ISOLATED SHOWERS IS RELATED TO THE SFC LOW. THIS FEATURE IS EXPECTED TO MOVE NE AND OUT OF AREA IN 24 HOURS. A 1019 MB HIGH SITUATED NEAR 26N60W HAS A RIDGE BETWEEN 45W AND 70W. THIS HIGH WILL CONTINUE TO MOVE SE AND IS FORECAST TO DISSIPATE IN A COUPLE OF DAYS AS A LOW PRES SYSTEM MOVES EWD ALONG 30N/31N. BROAD CYCLONIC FLOW...BOTH AT THE SURFACE AND ALOFT...DOMINATES THE REMAINDER OF THE REGION TO THE E OF THE HIGH AND N OF 20N. A DYING COLD FRONT REMAINS OVER THE E ATLC AND RUNS FROM 30N20W TO 25N51W THEN CONTINUES AS A TROUGH TO 24N42W. $$ GR