000 AXNT20 KNHC 172348 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON AUG 17 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... AS OF 2100 UTC...THE CIRCULATION OF TROPICAL DEPRESSION ANA HAS DISSIPATED INDICATED BY REPORTS FROM AN AIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT. THE REMNANTS OF ANA ARE NEAR 17.5N 68.0W...OR ABOUT 140 MILES...225 KM...WEST-SOUTHWEST OF SAN JUAN PUERTO RICO AND ABOUT 145 MILES...230 KM...EAST-SOUTHEAST OF SANTO DOMINGO IN THE DOMINICAN REPUBLIC. MAXIMUM SUSTAINED WINDS ARE NEAR 30 KT WITH GUSTS UP TO 40 KT. THE REMNANTS OF ANA WILL CONTINUE TO MOVE TOWARD THE WEST-NORTHWEST NEAR 21 KT AS A TROPICAL WAVE...AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE OVER THE NEXT DAY OR TWO...TAKING THE SYSTEM OVER HISPANIOLA LATER TONIGHT. HEAVY RAINFALL AND GUSTY WINDS MAY THREATEN HISPANIOLA AND CUBA OVER THE NEXT COUPLE OF DAYS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS CURRENTLY NW OF THE SYSTEM FROM 17N-24N BETWEEN 68W-75W...AFFECTING MUCH OF HISPANIOLA...ERN CUBA...AND THE SE BAHAMAS. THE CENTER OF HURRICANE BILL AT 17/2100 UTC IS NEAR 14.6N 46.7W...OR ABOUT 975 MILES...1570 KM...EAST OF THE LESSER ANTILLES. THE ESTIMATED CENTRAL PRESSURE IS 969 MB. MAXIMUM SUSTAINED WIND SPEEDS REMAIN AT 80 KT WITH GUSTS UP TO 100 KT. HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 30 MILES...45 KM...FROM THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 145 MILES...230 KM. INTENSIFICATION IS EXPECTED...AND BILL COULD BECOME A MAJOR HURRICANE BY WED. PLEASE READ THE LATEST FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS TCMAT3/ WTNT23 KNHC FOR MORE DETAILS. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS CURRENTLY FROM 11N-19N BETWEEN 42W-50W. ...TROPICAL WAVES... A TROPICAL WAVE EXTENDS FROM 17N33W TO 9N27W MOVING W NEAR 20 KT. THE AXIS IS BEING STRETCHED SE TO NW DUE TO INTERACTION WITH THE CIRCULATION OF HURRICANE BILL. THE WAVE LIES JUST AHEAD OF A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. ISOLATED MODERATE CONVECTION IS EMBEDDED WITHIN THE ITCZ FROM 7N-9N BETWEEN 29W-32W. A TROPICAL WAVE IS ALONG 95W S OF 22N MOVING W NEAR 15 KT...STRETCHING FROM THE SOUTHWESTERN GULF OF MEXICO...ACROSS THE ISTHMUS OF TEHUANTEPEC INTO THE EASTERN PACIFIC OCEAN. THE WAVE IS EMBEDDED IN A LARGE AREA OF DEEP LAYER MOISTURE OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. AN UPPER LEVEL LOW IS LOCATED TO THE W OF THE WAVE AXIS NEAR 20N99W ENHANCING SHOWERS AND THUNDERSTORMS ACROSS THE SW GULF OF MEXICO...YUCATAN PENINSULA...SW MEXICO AND INTO THE E PACIFIC. IT IS DIFFICULT TO SAY WHICH AREA OF SHOWERS IS DIRECTLY ASSOCIATED WITH THE WAVE. HOWEVER...SCATTERED MODERATE CONVECTION IS WITHIN 100 NM EITHER SIDE OF THE WAVE AXIS S OF 20N. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 14N16W 10N25W 11N36W 13N42W 9N50W 10N63W. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS ALONG THE AFRICAN COAST FROM 9N-12N BETWEEN 13W-16W. SCATTERED MODERATE CONVECTION IS FROM 7N-9N BETWEEN 33W-38W. ...DISCUSSION... THE GULF OF MEXICO... SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE MAJORITY OF THE GULF OF MEXICO. ACTIVITY ACROSS THE N GULF N OF 27N BETWEEN 82W-93W IS ENHANCED BY THE REMNANTS OF T.D. CLAUDETTE CURRENTLY NEAR 33.4N 88.6W OVER THE ALABAMA/MISSISSIPPI STATE BORDER. A TROPICAL WAVE ALONG 95W IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS IN THE SW GULF S OF 19N BETWEEN 92W-96W. THIS ACTIVITY IS ENHANCED BY UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL LOW OVER S MEXICO NEAR 20N99W AND AN UPPER LEVEL RIDGE ACROSS THE MAJORITY OF THE CENTRAL AND E GULF CENTERED NEAR 29N88W. THIS UPPER LEVEL DIFFLUENCE IS ALSO SUPPORTING SHOWERS/THUNDERSTORMS ACROSS THE YUCATAN PENINSULA. UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER RIDGE OVER THE GULF AND ANOTHER UPPER LEVEL LOW OVER CUBA NEAR 20N77W IS SUPPORTING SHOWERS/THUNDERSTORMS ALONG THE ERN GULF S OF 27N E OF 84W INCLUDING THE W COAST OF FLORIDA. EXPECT SHOWERS/THUNDERSTORMS TO CONTINUE ACROSS THE MAJORITY OF THE GULF DUE TO THE REMNANTS OF CLAUDETTE...AND THE APPROACH OF THE REMNANTS OF T.D. ANA. THE CARIBBEAN SEA... SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE NW CARIBBEAN N OF 19N BETWEEN 77W-84W AFFECTING THE MAJORITY OF CUBA. THIS ACTIVITY IS ENHANCED BY UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER LEVEL RIDGE OVER THE CENTRAL AND ERN GULF OF MEXICO AND AN UPPER LEVEL LOW NEAR 20N77W. NUMEROUS SHOWERS/THUNDERSTORMS ARE ACROSS CENTRAL AMERICA INCLUDING COSTA RICA AND PANAMA DUE TO THE PROXIMITY OF THE E PACIFIC ITCZ. NUMEROUS SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE MAJORITY OF COLUMBIA AND VENEZUELA DUE TO BROAD LOW PRESSURE ACROSS THE AREA AND AN UPPER LEVEL DIFFLUENT ZONE ALOFT. THE REMAINDER OF THE CARIBBEAN IS UNDER DRY AIR AND SUBSIDENCE ALOFT PROVIDING GENERALLY FAIR WEATHER EXCEPT FOR PUERTO RICO AND HISPANIOLA WHICH ARE STILL BEING AFFECTED BY THE REMNANTS OF T.D. ANA...SEE ABOVE. A DRY SAHARAN AIR LAYER IS E OF 64W SUPPORTING THE FAIR WEATHER ACROSS THE FAR E CARIBBEAN AND LESSER ANTILLES. THE ATLANTIC OCEAN... SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS MUCH OF THE WRN ATLC. A SURFACE TROUGH EXTENDS ACROSS THE NW BAHAMAS FROM 24N78W TO 31N71W SUPPORTING SHOWERS/THUNDERSTORMS WITHIN 200 NM NW OF THE TROUGH AXIS. THIS ACTIVITY IS ENHANCED BY UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL RIDGE OVER THE ERN GULF OF MEXICO AND AN UPPER LOW OVER CUBA NEAR 20N77W. A SECOND SURFACE TROUGH IS ACROSS THE SE BAHAMAS FROM 20N74W TO 24N70W AHEAD OF THE REMNANTS OF T.D. ANA. SURFACE CONVERGENCE NEAR THE TROUGH AND REMNANTS OF T.D. ANA ARE SUPPORTING SHOWERS/THUNDERSTORMS FROM 19N-26N BETWEEN 69W-75W. ELSEWHERE ACROSS THE ATLC...A BROAD SURFACE RIDGE DOMINATES ANCHORED BY A PAIR OF 1024 MB SURFACE HIGHS CENTERED NEAR 32N65W AND 32N33W. IN THE UPPER LEVELS...AN UPPER LEVEL TROUGH IS N OF 24N BETWEEN 43W-65W. AN UPPER LEVEL RIDGE CENTERED NEAR 26N39W DOMINATES THE ERN ATLC SUPPORTING DRY AIR AND SUBSIDENCE N OF 26N E OF 40W. $$ WALTON