000 AXNT20 KNHC 100555 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT THU MAY 10 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0530 UTC. ...SPECIAL FEATURE... SUBTROPICAL STORM ANDREA WAS CENTERED NEAR 30.5N 79.8W AT 10/0300 UTC OR ABOUT 135 MILES SE OF SAVANNAH GEORGIA AND 115 MILES NE OF DAYTONA BEACH FLORIDA. ANDREA IS NEARLY STATIONARY WITH NO SIGNIFICANT MOTION EXPECTED OVER THE NEXT 24 HOURS. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003 MB. MAXIMUM SUSTAINED WINDS ARE 40 KT WITH GUSTS TO 50 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/ WTNT21 KNHC FOR MORE DETAILS. MOST OF THE SIGNIFICANT WEATHER REMAINS ON THE EASTERN HALF OF THE CYCLONE WITH SCATTERED MODERATE CONVECTION NOTED FROM 28N-33N BETWEEN 77W-79W. BECAUSE ANDREA IS EXPECTED TO REMAIN OVER COOL WATERS IT SHOULD GRADUALLY WEAKEN. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 8N13W 6N25W 4N35W EQ50W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE AXIS BETWEEN 19W-25W. SIMILAR ACTIVITY LIES FROM THE 1S-8N BETWEEN 25W-37W. ...DISCUSSION... GULF OF MEXICO... DEEP LAYER N TO NW FLOW ON THE W SIDE OF ANDREA'S LARGE CIRCULATION IS ENHANCING SUBSIDENCE ABOVE THE ERN HALF OF THE GULF PROVIDING WIDESPREAD CLEAR SKIES AND FAIR WEATHER. MOST OF THE SMOKE PLUMES ORIGINATING FROM FIRES IN FLORIDA AND S GEORGIA HAVE NOW SPREAD BOTH TOWARD THE BAY OF CAMPECHE AND INTO THE WRN ATLC...STEERED BY THE DIFFLUENT LOW-LEVEL FLOW BETWEEN ANDREA AND A WEAK 1016 MB HIGH PRES OFF THE COAST OF LOUISIANA. THE HIGH IS PRODUCING MOSTLY LIGHT 5-15 KT WINDS ACROSS THE GULF AIDING IN THE TRANQUIL CONDITIONS. SEAS HAVE ALSO CONTINUED TO COME DOWN ACROSS THE GULF WITH MOST BUOYS/SHIPS NOW IN THE 2-3 FT RANGE. FAIRLY LIGHT WINDS AND MOSTLY FAIR WEATHER IS EXPECTED TO CONTINUE THROUGH FRI AS WEAK HIGH PRES REMAINS STATIONARY IN THE MID-GULF...THOUGH SCATTERED SHOWERS/TSTMS POSSIBLE IN THE NW PORTION WITH THE DYNAMICS AHEAD OF AN APPROACHING MID TO UPPER LOW/TROUGH. CARIBBEAN SEA... THE CONTINUED WEAK PRES PATTERN IN THE WRN CARIB IS ALLOWING WINDS TO REMAIN VERY LIGHT...GENERALLY 10 KT OR LESS. THE TRADES INCREASE TO MORE TYPICAL VALUES IN THE CENTRAL AND ERN CARIB...15-20 KT...AS SFC RIDGING FROM THE NE HAS BUILT INTO THE REGION. IN THE UPPER LEVELS...A TROUGH/RIDGE PATTERN PERSISTS WITH ABUNDANT SUBSIDENCE NOTED N OF 12N W OF 78W. PRONOUNCED UPPER DIFFLUENCE BETWEEN THE TROUGH/RIDGE IS HELPING TO SUPPORT THE SCATTERED MODERATE CONVECTION FROM 13N-15N BETWEEN 77W-79W AND ALSO JUST SE OF JAMAICA. SW UPPER FLOW IS TRANSPORTING A SWATH OF MOISTURE NE THROUGH THE CENTRAL CARIB INTO THE ATLC. MORE IMPRESSIVE CONVECTION ASSOCIATED WITH THE ITCZ HAS RECENTLY FLARED UP IN THE SW CARIB S OF 12N E OF 81W. ATLANTIC... SUBTROPICAL STORM ANDREA REMAINS THE AREA OF FOCUS THIS EVENING...FOR DETAILS REFER TO THE SPECIAL FEATURE SECTION ABOVE. SWELL ASSOCIATED WITH ANDREA HAS CONTINUED TO OVERALL STEADILY SUBSIDE OVER THE LAST COUPLE OF DAYS. HOWEVER...SEAS HAVE BEEN SLOWER TO RELAX OFF THE GEORGIA THROUGH SOUTHERN NORTH CAROLINA COAST...DOWNSTREAM FROM A MORE FAVORABLE FETCH ASSOCIATED WITH THE INTERACTION BETWEEN ANDREA AND A 1026MB HIGH PRES OFF THE MID ATLC COAST NEAR 37N55W. AN UPPER DIFFLUENT ZONE TO THE E OF ANDREA...BETWEEN THE STORM'S EMBEDDED TROUGH AND RIDGING TO THE E...IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS BETWEEN 62W-75W. FARTHER E...A SFC TROUGH IS ALONG 32N41W 26N50W WITH A WEAK 1018MB LOW ON THE TROUGH NEAR 28N47W. ISOLATED SHOWERS POSSIBLE WITHIN 90NM EITHER SIDE OF THE TROUGH. AN UPPER LOW IS OVER THESE SFC FEATURES NEAR 26N47W. THE SRN PERIPHERY OF A STATIONARY 1025MB HIGH SE OF THE AZORES NEAR 36N20W DOMINATES THE E ATLC AREA E OF 40W. UW-CIMMS SAHARAN AIR ANALYSIS DEPICTS A FAIRLY DENSE AREA OF DUST E OF ABOUT 30W. THIS VERY DRY AIR HAS CLEARED MOST OF THE LOW TO MID LEVEL CLOUDS IN THE ERN-MOST ATLC. $$ WILLIS