000 AXNT20 KNHC 020945 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT MAY 02 2009 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0730 UTC. ...THE ITCZ... THE ITCZ AXIS EXTENDS FROM W AFRICA AT 05N06W TO 02N20W TO THE EQUATOR AT 28W TO 01S35W TO NE BRAZIL NEAR 03S40W. WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 60 NM N OF THE ITCZ AND 180 NM S OF THE ITCZ E OF 20W. SCATTERED MODERATE CONVECTION CAN ALSO BE FOUND FROM 02N TO 05N BETWEEN 20W AND 27W. ...DISCUSSION... GULF OF MEXICO... AN UPPER TROUGH LIES ACROSS THE GULF OF MEXICO FROM THE NE GULF THROUGH THE WESTERN BAY OF CAMPECHE...WITH STRONG SUBSIDENCE OVER MUCH OF THE GULF N OF 24N WHERE FAIR WEATHER PREVAILS ON THE EASTERN SIDE OF THE TROUGH AXIS. MOSTLY MID TO HIGH LEVEL CLOUDINESS IS FOUND S OF 24N WHERE THE SUBTROPICAL UPPER JET IS TRANSPORTING MOISTURE EASTWARD OVER THE AREA. THERE IS NO SIGNIFICANT CONVECTION OVER GULF WATERS AT THIS TIME. AT THE SURFACE...SOUTHEASTERLY FLOW CAN BE FOUND OVER MOST OF THE AREA. THE STRONGEST WINDS...IN THE 15 TO 20 KT RANGE...ARE IN THE WESTERN GULF WHERE THE GRADIENT BETWEEN THE WESTERN EDGE OF THE ATLC RIDGE AXIS OVER THE EASTERN GULF OF MEXICO AND THE TROUGHING OVER TEXAS AND NORTHEASTERN MEXICO IS STRONGEST. MEAN WINDS IN AND JUST S OF THE FLORIDA KEYS HAVE DIMINISHED BELOW 20 KT AS THE WESTERN EDGE OF THE ATLC RIDGE HAS WEAKENED SLIGHTLY OVER THE LAST 24 HOURS. HOWEVER...THE 2334 QUIKSCAT PASS SHOWED WINDS TO 25 KT ALONG THE COAST OF CUBA WITHIN THE STRAITS OF FLORIDA. LITTLE CHANGE IN THE PATTERN IS EXPECTED UNTIL LATE SUN WHEN A COLD FRONT WILL PUSH SOUTH TO THE TEXAS COAST WHILE HIGH PRES IN THE CENTRAL ATLC MOVES SOUTHWARD...SHIFTING THE HIGHER WINDS IN THE GULF SOUTHWARD. CARIBBEAN SEA... AN UPPER LEVEL RIDGE CURRENTLY LIES OVER MUCH OF THE CARIBBEAN ON THE SE SIDE OF THE TROUGH OVER THE GULF OF MEXICO. THERE IS LITTLE CONVECTION OVER FORECAST WATERS WITH THE EXCEPTION OF SOME SCATTERED SHOWERS IN THE GULF OF HONDURAS. TO THE EAST...A DEEP LAYER TROUGH NE OF THE CARIBBEAN IS FOCUSING MOIST AIR OVER THE LEEWARD ISLANDS WHERE PRECIPITABLE WATER VALUES AND SHOWER ACTIVITY HAVE BEEN INCREASING OVER THE LAST 24 HOURS. DRY AIR ALOFT IS CURRENTLY WRAPPING S OF THE UPPER LEVEL LOW ASSOCIATED WITH THIS TROUGH...PASSING OVER THE NE CARIBBEAN. AT THE SURFACE...THE QUIKSCAT PASS FROM 2338 UTC AND THE ASCAT PASS FROM 0154 UTC SHOW A BROAD AREA OF WINDS IN THE 20 TO 25 KT RANGE ACROSS THE CENTRAL CARIBBEAN...WITH THE HIGHEST WINDS ALONG THE COAST OF COLOMBIA AND IN THE WINDWARD PASSAGE. ELSEWHERE...TRADE WINDS ARE GENERALLY 20 KT OR LESS. TRADE WINDS ARE EXPECTED TO DIMINISH SLIGHTLY OVER THE NEXT DAY AS HIGH PRESSURE IN THE N CENTRAL ATLC MOVES NORTHEASTWARD. ATLANTIC OCEAN... THE WEATHER OVER THE ATLC IS DOMINATED BY A HIGH PRESSURE RIDGE FROM 40N47W TO 32N68W INTO N FLORIDA AND TO 29N89W. STRONG SUBSIDENCE CAN BE FOUND BETWEEN 59W AND 70W. A DEEP LAYER TROUGH CAN BE FOUND IN THE VICINITY OF 58W FROM 15N TO 25N. THIS TROUGH IS SENDING LOW TO MID LEVEL MOISTURE THROUGH THE LESSER ANTILLES NORTHWARD TO THE SURFACE TROUGH. SCATTERED MODERATE CONVECTION ASSOCIATED WITH THE TROUGH CAN BE FOUND FROM FROM 23N TO 26N BETWEEN 53W AND 57W AND FROM 22N TO 24N BETWEEN 47W AND 51W. THE ASCAT PASS FROM 0158 SHOWS THE STRONGEST WINDS...AROUND 20 KT....ALONG THE NW SIDE OF THIS TROUGH INTO THE SOUTHERN BAHAMAS AND SOUTHERN STRAITS OF FLORIDA BETWEEN THE SURFACE TROUGH AND THE RIDGE AXIS. ELSEWHERE...TRADE WINDS OVER 20 KT ARE CURRENTLY CONFINED S OF 13N FROM 40W TO 60W AND GENERALLY FROM 13N TO 21N E OF 40W. SUBSIDENCE S OF 11N E OF 42W IS PROHIBITING WIDESPREAD DEEP CONVECTION ALONG MUCH OF THE ITCZ. OVER THE NEXT 24 HOURS...LOOK FOR THE DEEP LAYER TROUGH TO BREAKDOWN AS THE UPPER LEVEL SYSTEM SHIFTS TO THE E AND MERGES WITH THE TROUGH CURRENTLY JUST N OF THE AREA ALONG 45W WHILE THE LOW LEVEL SYSTEM CONTINUES W WITH THE MEAN FLOW S OF THE RIDGE AXIS. $$ SCHAUER CLARK