000 AXPZ20 KNHC 082129 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SUN AUG 08 2010 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2115 UTC. ...SPECIAL FEATURE... AT 08/2100 UTC...THE CENTER OF TROPICAL STORM ESTELLE WAS LOCATED NEAR 17.9N 111.1W MOVING TOWARD THE WEST OR 275 DEGREES AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1001 MB. MAXIMUM SUSTAINED WINDS HAVE DECREASED TO 40 KT WITH GUSTS TO 50 KT. THE TREK OVER COOLER WATERS AND THE ENTRAINMENT OF DRY AIR HAS TAKEN ITS TOLL ON ESTELLE WITH VISIBLE SATELLITE IMAGERY INDICATING THAT THE LOW-LEVEL CIRCULATION OF ESTELLE HAS SEPARATED FROM THE MID-LEVEL CIRCULATION AND IS NOW EXPOSED SOUTHEAST OF THE DEEP CONVECTION. THIS WEAKENING TREND IS EXPECTED TO CONTINUE AND ESTELLE IS FORECAST TO BECOME A TROPICAL DEPRESSION WITHIN THE NEXT 18-24 HOURS. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/ WTPZ22 KNHC FOR MORE DETAILS. ...ITCZ... THE ITCZ AXIS IS ALONG 12N87W TO 14N93W TO 14N96W TO 15N105W TO 11N120W TO 10N135W. NUMEROUS MODERATE SCATTERED STRONG WITHIN 120 NM S OF AXIS AND 60 NM N OF AXIS BETWEEN 95W AND 100W. SCATTERED MODERATE ISOLATED STRONG WITHIN 240 NM S OF AXIS BETWEEN 100W AND 104W...WITHIN 150 NM S OF AXIS BETWEEN 106W AND 111W...AND WITHIN 90 NM N OF AXIS BETWEEN 114W AND 125W. ...DISCUSSION... AN UPPER LEVEL ANTICYCLONE LOCATED NEAR 23N130W WITH AN UPPER RIDGE EXTENDING NW BEYOND 32N135W. THIS ANTICYCLONE IS IN THE PROCESS OF MERGING WITH ANOTHER ANTICYCLONE CENTERED IN THE DEEP TROPICS NEAR 17N132W. TOGETHER THESE FEATURES GOVERN THE FLOW OVER THE AREA N OF THE ITCZ AND W OF 126W. VERY DRY AIR ALOFT WITH MODERATE TO STRONG SUBSIDENCE IS PRESENT ACROSS THE SAME GENERAL AREA. A SHARP UPPER LEVEL TROUGH ENTERS THE FORECAST AREA NEAR 32N120W AND CONTINUES SSW THROUGH 20N125W. THIS TROUGH WAS BECOMING IN PHASE WITH A CYCLONIC CIRCULATION NEAR 20N121W. THIS AREA OF TROUGHINESS SEPARATES THE MERGING ANTICYCLONES NOTED ABOVE FROM ANOTHER UPPER LEVEL ANTICYCLONE LOCATED OVER E-CENTRAL MEXICO NEAR 20N98W WITH A RIDGE AXIS EXTENDING WNW INTO THE E PACIFIC NEAR 23N117W. TROPICAL STORM ESTELLE IS EMBEDDED IN THE FAIRLY STRONG UPPER LEVEL SOUTHEASTERLY FLOW TO THE SW OF THIS ANTICYCLONE WHICH HAS TAKEN ITS TOLL ON THE SYSTEM. A WEAK UPPER LEVEL TROUGH AXIS EXTENDS FROM A CYCLONIC CIRCULATION OVER CENTRAL WWD ACROSS NRN MEXICO ALONG 29N/30N. ZONAL/EASTERLY FLOW PREVAILS ACROSS THE REMAINDER OF THE DISCUSSION AREA IN THE DEEP TROPICS S OF 12N. UPPER LEVEL MOISTURE RESULTING FROM ITCZ CONVECTION IS BEING ADVECTED TO THE WEST AS A RESULT OF THE PERSISTENT EASTERLY WINDS. UPPER LEVEL DIFFLUENCE IS HELPING TO INDUCE CONVECTION ALONG THE ITCZ PARTICULARLY IN THE AREA BETWEEN 90W AND 115W. AT THE SURFACE...A RIDGE DOMINATES THE NORTHERN WATERS ORIGINATING FROM 1029 MB HIGH PRES CENTERED NW OF THE AREA NEAR 36N145W ENTERING THE DISCUSSION AREA AT 32N136W AND CONTINUING THROUGH 22N115W. NOAA CORPS SHIP 'MCARTHUR II' NOW LOCATED NEAR 28N134W HAS REPORTED NNE WINDS OF NEAR 20 KT DURING THE PAST FEW HOURS ALONG WITH 9 FT SEAS. THE FORECAST KEEPS AN AREA OF 15-20 KT WINDS N OF 28N BETWEEN 124W AND 132W FOR THE NEXT 12 HOURS OR SO. GLOBAL MODELS TRANSLATE THIS AREA TO THE SW OVER THE NEXT 24-36 HOURS AND GRADUALLY DIMINISHES THE WIND FIELD BELOW 20 KT AS A BROAD AREA OF MODERATE TRADES DEVELOPS W OF 133W. ELSEWHERE FARTHER WEST...A WEAK SURFACE TROUGH EMBEDDED WITHIN THE ITCZ EXTENDS FROM 13N135W TO 09N140W. THE TROUGH IS FORECAST TO DRIFT WESTWARD AT AROUND 5-10 KT OVER THE NEXT FEW DAYS. DISTURBANCES ALONG THE ITCZ CONTINUE TO PRODUCE AN AREA OF S TO SW WINDS OF 20-25 KT S OF THE ITCZ TO 08N BETWEEN 95W AND 125W AS CAPTURED BY DESCENDING ASCAT PASSES AT 1628 UTC AND 1808 UTC. COMBINED SEAS ARE 8 TO 12 FT FROM LONG PERIOD SW SWELL AND FRESHLY GENERATED WIND SEAS. THIS OVERALL WEATHER PATTERN WILL PERSIST DURING THE NEXT FEW DAYS. CROSS EQUATORIAL SW SWELLS DOMINATING THE MAJORITY OF THE FORECAST WATERS WILL GRADUALLY DECAY THROUGH MON. A NEW SWELL TRAIN WITH PERIODS OF 15-16 SECONDS IS EXPECTED TO CROSS THE EQUATOR BETWEEN 105W AND 125W MON...AND SPREAD OVER MOST OF THE BASIN S OF 13N-15N BY LATE TUE. $$ COBB