000 AXNT20 KNHC 232347 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN AUG 23 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... HURRICANE BILL IS CENTERED NEAR 46.2N 57.9W AT 24/0000 UTC OR ABOUT 200 NM W OF CAPE RACE NEWFOUNDLAND MOVING NE AT 30 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 970 MB. MAXIMUM SUSTAINED WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. NUMEROUS SHOWERS ARE FROM 46N-51N BETWEEN 48W-58W TO THE NE OF THE CENTER OF BILL. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT3/WTNT33 KNHC AND THE FULL FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 24W S OF 19N MOVING W NEAR 18 KT. SATELLITE IMAGERY AND CIMSS WAVETRAK GUIDANCE INDICATE LOW TO MIDDLE LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE AXIS. THIS WAVE ALSO COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED SHOWERS ARE NOTED FROM 9N-20N BETWEEN 21W-27W. TROPICAL WAVE EXTENDS FROM 9N49W TO 17N52W MOVING W NEAR 23 KT. AN INVERTED-V CLOUD SIGNATURE IS OBSERVED IN THE LOW-LEVEL CLOUD FIELD ON SATELLITE IMAGERY. THE WAVE ALSO COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. AS THE WAVE CONTINUES TO MOVE WWD BENEATH MOIST SLY FLOW ALOFT DUE TO AN UPPER LEVEL LOW CENTERED NEAR 23N58W... SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 14N-18N BETWEEN 47W-57W AND IS FORECAST TO CONTINUE BEING ENHANCED BY THE UPPER LEVEL FEATURE. TROPICAL WAVE IS ALONG 70W S OF 18N MOVING W NEAR 13 KT. THIS WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM THAT HAS BEEN TRACKING ACROSS THE SERN AND NOW S/CENTRAL CARIBBEAN OVER THE PAST 24 HOURS. SCATTERED MODERATE CONVECTION IS FROM 10N-15N BETWEEN 67W-75W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 15N17W 13N23W 12N25W 10N33W 13N48W 13N52W 11N67W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 12N-17N BETWEEN 16W-22W. AN AREA OF SIMILAR ACTIVITY IS FROM 10N-13N BETWEEN 25W-28W. ELSEWHERE...SCATTERED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN 60W-66W ACROSS NE VENEZUELA AND PORTIONS OF THE FAR SE CARIBBEAN SEA. ...DISCUSSION... GULF OF MEXICO... AS OF 2100 UTC...A COLD FRONT CROSSES THE CENTRAL FLORIDA PENINSULA AND ENTERS THE ERN GULF NEAR SARASOTA CONTINUING SW TO 25N87W WHERE IT BECOMES A STATIONARY FRONT ALONG 24N92W 26N94W. THIS FRONTAL BOUNDARY IS SUPPORTED BY A SHARP UPPER LEVEL TROUGH WITH AXIS ALONG THE ERN CONUS TO SRN ALABAMA AND OVER THE N/CENTRAL GULF TO 25N93W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 60 NM OF THE COLD FRONT AND COVER AN AREA FROM 21N-25N BETWEEN 89W-96W IN THE VICINITY OF THE STATIONARY FRONT. AN EXTENSION OF UPPER LEVEL TROUGHING AND CYCLONIC CURVATURE IS ALSO OVER THE CENTRAL BAY OF CAMPECHE THAT IS ENHANCING THIS CONVECTION AS WELL AS GENERATING SCATTERED SHOWERS AND TSTMS S OF 22N ACROSS THE YUCATAN PENINSULA. NORTH OF THE FRONTAL BOUNDARY...A MUCH DRIER AIRMASS IS TAKING HOLD PROMOTING SUBSIDENCE...SINKING AIR AND FAIR WEATHER CONDITIONS THIS EVENING AND OVERNIGHT ACROSS THE NRN GULF WATERS. CARIBBEAN SEA... A BROAD UPPER LEVEL RIDGE DOMINATES THE CARIBBEAN CENTERED OVER THE WINDWARD PASSAGE NEAR 19N74W. UPPER LEVEL DIFFLUENCE ON MOIST SWLY FLOW ALOFT BETWEEN THIS RIDGE AND THE UPPER LEVEL TROUGHING OVER THE CENTRAL BAY OF CAMPECHE IS SUPPORTING SCATTERED SHOWERS AND TSTMS ACROSS THE YUCATAN PENINSULA AND PORTIONS OF CENTRAL CUBA. ON THE SRN PERIPHERY OF THE UPPER LEVEL RIDGE...UPPER LEVEL DIFFLUENCE IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE SW CARIBBEAN S OF 16N W OF 79W INCLUDING PORTIONS OF NICARAGUA AND HONDURAS. FARTHER TO THE E...UPPER LEVEL DIFFLUENCE ALONG WITH THE TROPICAL WAVE ALONG 70W IS PRODUCING SCATTERED SHOWERS AND ISOLATED TSTMS FROM 10N-15N BETWEEN 67W-75W. MODERATE TO FRESH TRADEWINDS CONTINUE ACROSS MUCH OF THE BASIN WITH THE STRONGEST WINDS EXPECTED IN THE CENTRAL CARIBBEAN AND NEAR THE COAST OF COLOMBIA THROUGH TUE. ATLANTIC OCEAN... A 1011 MB LOW IS CENTERED OVER SOUTH CAROLINA AND EXTENDS A COLD FRONT OVER THE SW NORTH ATLC TO NEAR FLAGLER BEACH FLORIDA AND ACROSS THE CENTRAL FLORIDA PENINSULA INTO THE GULF OF MEXICO. SCATTERED SHOWERS AND ISOLATED TSTMS ACCOMPANY THIS FRONTAL BOUNDARY AND ARE WITHIN 120 NM E OF THE FRONT...INCLUDING A PORTION OF THE SE FLORIDA PENINSULA. THIS ACTIVITY IS PRIMARILY SUPPORTED ALOFT BY AN UPPER LEVEL TROUGH ACROSS THE ERN CONUS AND THE ASSOCIATED UPPER LEVEL DIFFLUENCE LOCATED E OF THE TROUGH AXIS. FARTHER TO THE E OVER THE REMAINDER OF THE SW NORTH ATLC...A SURFACE RIDGE OF HIGH PRESSURE EXTENDS FROM A 1028 MB HIGH CENTERED NEAR 36N47W. THE RIDGE STRETCHES THROUGH BERMUDA TO THE NW BAHAMAS. ACROSS THE CENTRAL ATLC...THE SURFACE RIDGE REMAINS IN CONTROL HOWEVER AN UPPER LEVEL LOW IS CENTERED NEAR 23N58W AND IS PROVIDING POSSIBLE SCATTERED SHOWERS FROM 17N-27N BETWEEN 50W-62W. THIS AREA IS LOCATED TO THE N AND NW OF THE TROPICAL WAVE ALONG APPROXIMATELY 51W. ELSEWHERE ACROSS THE ATLC E OF 50W...THE AFOREMENTIONED SURFACE RIDGE ANCHORED BY THE 1028 MB HIGH CENTERED NEAR 36N47W IS PROVIDING THE REMAINDER OF THE BASIN WITH NE TO ELY TRADES OF UP TO 25 KT. $$ HUFFMAN