000 AXNT20 KNHC 221753 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT AUG 22 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... THE CENTER OF HURRICANE BILL AT 22/1800 UTC IS NEAR 36.0N 68.8W OR ABOUT 370 MILES...595 KM...SOUTH OF NANTUCKET MASSACHUSETTS. BILL IS MOVING TO THE NORTH AT 20 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 964 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 85 KT WITH GUSTS TO 105 KT. PLEASE READ THE FORECAST/ADVISORY UNDER AFOS/WMO HEADERS TCMAT3/WTNT23 KNHC AND THE PUBLIC ADVISORY UNDER TCPAT3/WTNT33 KNHC FOR MORE DETAILS. BILL IS A CATEGORY TWO HURRICANE ON THE SAFFIR-SIMPSON SCALE AND IS TRAVERSING COOLER WATERS THUS A WEAKENING TREND IS ON GOING. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 33N-38N BETWEEN 64W-70W. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG THE COAST OF W AFRICA AT 13W S OF 17N MOVING W AT 10 KT. SCATTERED SHOWERS ARE FROM 8N-20N BETWEEN 13W-19W. A TROPICAL WAVE IS ALONG 38W S OF 18N MOVING W AT 20-25 KT. A 1010 MB LOW IS EMBEDDED ON THE WAVE AXIS AT 12N38W. A SSMI TOTAL PRECIPITABLE WATER MAXIMUM IS NOTED. ISOLATED MODERATE CONVECTION IS W OF THE WAVE AXIS FROM 11N-15N BETWEEN 39W-45W. A TROPICAL WAVE IS ALONG 63W S OF 17N MOVING 15-20 KT. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS OVER THE WINDWARD ISLANDS FROM 9N-12N BETWEEN 59W-64W. ...THE ITCZ... THE ITCZ IS CENTERED ALONG 10N14W 13N30W 11N44W 8N50W 10N61W. BESIDES THE CONVECTION MENTIONED IN THE TROPICAL WAVE SECTION... SCATTERED MODERATE CONVECTION IS FROM 10N-12N BETWEEN 21W-24W. ...DISCUSSION... THE GULF OF MEXICO... A SURFACE TROUGH IS OVER N FLORIDA AND THE NE GULF OF MEXICO ALONG 30N82W 27N86W. WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE TROUGH AXIS. SIMILAR CONVECTION IS ALONG THE COAST OF LOUISIANA FROM 28N-30N BETWEEN 88W93W DUE TO PREFRONTAL ACTIVITY. A 1016 MB HIGH IS OVER THE CENTRAL GULF NEAR 25N90W. FAIR WEATHER IS OVER THE CENTRAL GULF. A SMALL AREA OF SCATTERED MODERATE CONVECTION IS OVER THE BAY OF CAMPECHE FROM 19N-21N BETWEEN 96W-97W. IN THE UPPER LEVELS...THE BASE OF AN UPPER LEVEL TROUGH IS OVER THE N GULF N OF 29N. AN UPPER LEVEL HIGH IS OVER THE YUCATAN PENINSULA NEAR 20N87W. EXPECT A TROUGH AND A COLD FRONT TO GO OVER N FLORIDA AND THE NE GULF OVER THE NEXT 24 HOURS WITH CONVECTION. THE CARIBBEAN SEA... A TROPICAL WAVE IS OVER THE E CARIBBEAN. SEE ABOVE. A 1008 MB LOW IS CENTERED OVER N COLOMBIA NEAR 10N75W. MODERATE TRADES ARE OVER THE CARIBBEAN SEA. SCATTERED MODERATE CONVECTION IS ALONG THE COAST OF PANAMA FROM 9N-10N BETWEEN 80W-81W. SIMILAR CONVECTION IS ALONG THE COAST OF NICARAGUA FROM 13N-15N BETWEEN 83W-85W. IN THE UPPER LEVELS...AN UPPER LEVEL LOW IS OVER THE YUCATAN PENINSULA. FURTHER E...A SMALL UPPER LEVEL HIGH IS NEAR JAMAICA. ZONAL FLOW IS OVER THE E CARIBBEAN E OF 70W. EXPECT... CONVECTION OVER THE E CARIBBEAN DUE TO THE TROPICAL WAVE OVER THE NEXT 24 HOURS. ALSO EXPECT MORE CONVECTION OVER THE SW CARIBBEAN AND CENTRAL AMERICA S OF NICARAGUA. THE ATLANTIC OCEAN... HURRICANE BILL IS NOW MOVING N AWAY FROM OUR AREA HOWEVER LONG PERIOD SWELL IS REACHING THE FLORIDA COAST. A SURFACE HIGH IS OVER THE CENTRAL ATLANTIC NEAR 37N47W. MOSTLY FAIR WEATHER IS OVER THE ATLANTIC FROM 20N-30N. CONVECTION IN THE TROPICS IS CONFINED TO THE TROPICAL WAVES. IN THE UPPER LEVELS...AN UPPER LEVEL LOW IS OVER THE W ATLANTIC NEAR 29N76W. AN UPPER LEVEL HIGH IS N OF THE LEEWARD ISLANDS NEAR 23N65W. A SMALL UPPER LEVEL LOW IS OVER THE CENTRAL ATLANTIC NEAR 27N50W. AN UPPER LEVEL HIGH IS OVER THE TROPICS NEAR 16N35W. ANOTHER UPPER LEVEL LOW IS W OF THE CANARY ISLANDS NEAR 30N25W. $$ FORMOSA