000 AXPZ20 KNHC 160958 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SUN AUG 16 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...SPECIAL FEATURES... HURRICANE GUILLERMO CENTERED AT 19.8N 137.4W AT 0900 UTC MOVING W OR 280 DEG AT 13 KT. MAXIMUM SUSTAINED WINDS ARE 85 KT WITH GUSTS TO 105 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 973 MB. GUILLERMO HAS AN 18 TO 20 NM EYE SURROUNDED BY NUMEROUS STRONG CONVECTION WITHIN 90 NM OVER THE W AND WITHIN 60 NM OVER THE E SEMICIRCLES OF CENTER. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS NOTED ELSEWHERE WITHIN 120 NM OVER THE N SEMICIRCLE. GUILLERMO IS EXPECTED TO CONTINUE TO WEAKEN AND BE A STRONG TROPICAL STORM TONIGHT AS HE MOVES OVER COOLER WATERS AND ENTRAINS DRY AIR AND ENCOUNTERS WIND SHEAR. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. THE SMALL REMNANT LOW PRES OF TROPICAL DEPRESSION NINE-E HAS WEAKENED INTO A TROUGH THAT EXTENDS NE FROM 11N140W TO 17N137W. SOUTHERLY WINDS AT 20 KT ARE OBSERVED WITHIN 240 NM E OF THIS TROUGH MERGING WITH THE SOUTHERLY WINDS OVER THE SOUTHERN SEMICIRCLE OF HURRICANE GUILLERMO. ...TROPICAL WAVES... A TROPICAL WAVE IS ANALYZED N OF 06N ALONG 86.5W WITH WESTWARD MOTION ESTIMATED AT 15 TO 20 KT OVER THE PAST 24 HOURS. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED ALONG THE WAVE AXIS WITHIN 60 NM OF 13N88W. A TROPICAL WAVE IS ANALYZED N OF 06N ALONG 99W AND HAS BEEN MOVING W AT 15 KT OVER THE PAST 24 HOURS. ISOLATED MODERATE AND STRONG CONVECTION IS NOTED WITHIN 180 NM OF THE WAVE AXIS. A TROPICAL WAVE IS ANALYZED FROM 04N TO 16N ALONG 115W AND HAS BEEN MOVING W AT 15 KT OVER THE PAST 24 HOURS. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS FLARING FROM 12N TO 18N WITHIN 150 NM E OF THE WAVE AXIS. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG 10N85W TO 09N94W TO 11N110W TO 09N20W TO 12N130W TO 09N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 150 NM EITHER SIDE OF A LINE FROM 05N77W TO 09N98W AND A LINE FROM 09N106W TO 09N112W TO 14N114W AND FROM 08N TO 14N BETWEEN 120W AND 140W. ...DISCUSSION... AN UPPER ANTICYCLONE AT 26N127W HAS A RIDGE EXTENDING SW ACROSS HURRICANE GUILLERMO TO A SHARP CREST AT 14N145W. A RIDGE ALSO EXTENDS NE TO A SHARP CREST AT 31N123W. ASSOCIATED DIFFLUENCE IS STILL VENTILATING CONVECTION AROUND THE HURRICANE GUILLERMO WITH THE DEBRIS MOISTURE ADVECTED NE TO THE SHARP CREST ALREADY MENTIONED. CONVECTION IS ENHANCED ALONG THE ITCZ BETWEEN 128W AND 145W...AND THE DEBRIS MOISTURE IS ADVECTED N ALONG 18N130W MERGING WITH THE DEBRIS MOISTURE FROM GUILLERMO. DRY UPPER AIR IS NOTED FROM 13N TO 27N W OF 137W...AND WILL SOON ENTRAIN INTO THE HURRICANE CIRCULATION. A SECOND UPPER ANTICYCLONE IS OVER CENTRAL AMERICA AT 18N101W AND DOMINATES THE UPPER LEVELS BETWEEN 92W AND 112W. SQUEEZED BETWEEN THE ANTICYCLONES IS A WELL DEFINED UPPER CYCLONE AT 22N116W WHICH IS MOVING W WITH TIME. A BAND OF DRY UPPER AIR IS NOTED FROM 32N119W TO 22N123W TO 15N110W. DEBRIS MOISTURE FROM ITCZ CONVECTION BETWEEN 105W AND 115W IS SPREADING N OVER THE E SEMICIRCLE OF THE CYCLONE. AN UPPER TROUGH EXTENDS SW ACROSS THE NORTHERN CARIBBEAN INTO A SMALL UPPER CYCLONE AT 19N90W WITH THE TROUGH CONTINUING S TO NEAR 14N92W. UPPER DIFFLUENCE IS ENHANCING CONVECTION OVER THE TROPICAL PACIFIC E OF 105W WITH THE DEBRIS MOISTURE REMAINING IN ROUGHLY THE SAME AREA. AT LOW LEVELS A SURFACE RIDGE EXTENDS INTO THE AREA AT 32N135W TO 10N110W. NW WINDS ARE AT 15 TO 20 KT ALONG THE W COAST OF THE BAJA PENINSULA. GAP WINDS...THE LATEST ASCAT PASS INDICATES NE WINDS AT 15 TO 20 KT ARE SURGING INTO THE GULF OF PAPAGAYO AND MAY OCCASIONALLY INCREASE TO 20 TO 25 KT OVER THE NEXT COUPLE OF DAYS AS EASTERLY TRADES ARE FAIRLY STRONG UPSTREAM IN W CARIBBEAN. $$ NELSON