000 AXPZ20 KNHC 072116 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT AUG 07 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 07/2100 UTC...THE CENTER OF TROPICAL STORM ESTELLE IS LOCATED NEAR 17.1N 108.7W MOVING TOWARD THE WEST OR 275 DEGREES AT 9 KT. A GENERAL WESTWARD MOTION IS EXPECTED OVER THE NEXT FEW DAYS. ESTIMATED MINIMUM CENTRAL PRESSURE IS 998 MB. MAXIMUM SUSTAINED WINDS ARE NOW 50 KT WITH GUSTS TO 60 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. THE MOST RECENT VISIBLE SATELLITE IMAGERY INDICATED THAT THE DEEP CONVECTION HAS WRAPPED INTO A LARGE CURVED BAND AND THE SYSTEM HAS BECOME BETTER ORGANIZED. AS NOTED EARLIER...ESTELLE HAS ABOUT 18 TO 24 HOURS OF STRENGTHENING BEFORE INCREASING SOUTHEASTERLY SHEAR...COOLER WATERS...AND A MORE STABLE ATMOSPHERE TAKES ITS TOLL ON THE SYSTEM. ...ITCZ... THE ITCZ AXIS IS ALONG 11N86W TO 11N88W TO 12N90W TO 14N104W TO 13N115W TO 12N120W TO 10N136W. SCATTERED MODERATE ISOLATED STRONG WITHIN 300 NM S OF AXIS BETWEEN 94W AND 100W...AND WITHIN 150 NM S OF AXIS BETWEEN 100W AND 104W. SCATTERED MODERATE TO STRONG WITHIN 240 NM S OF AXIS BETWEEN 104W AND 110W. SCATTERED MODERATE WITHIN 60 NM OF AXIS BETWEEN 110W AND 114W...AND WITHIN 75 NM OF AXIS BETWEEN 117W AND 122W. ...DISCUSSION... AN UPPER LEVEL ANTICYCLONE DOMINATING THE NW WATERS HAS MIGRATED TO NEAR 26N135W WITH AN UPPER RIDGE EXTENDING BEYOND 32N137W. A SECOND UPPER LEVEL ANTICYCLONIC CIRCULATION IS LOCATED OVER THE RED RIVER VALLEY OF THE U.S. WITH THE ASSOCIATED RIDGE EXTENDING WWD ALONG THE U.S. MEXICAN BORDER. A NARROW SHEAR AXIS ACROSS NRN MEXICO ALONG 25N SEPARATED THE U.S. ANTICYCLONE FROM ANOTHER ANTICYCLONE NEAR 18N104W WHICH WAS SITUATED TO THE EAST OF TROPICAL STORM ESTELLE. ESTELLE IS NOW EMBEDDED IN THE UPPER LEVEL SOUTHEASTERLY FLOW TO THE SW OF THE ANTICYCLONE. AN UPPER LEVEL TROUGH ENTERS THE FORECAST AREA NEAR 32N119W AND CONTINUES SW THROUGH 22N125W THEN CONTINUES AS A SHEAR AXIS THROUGH 21N135W TO A SMALL CYCLONIC CIRCULATION W OF THE AREA NEAR 19N144W. VERY DRY AIR ALOFT WITH MODERATE TO STRONG SUBSIDENCE IS PRESENT ACROSS THE REGION N OF 18N AND W OF 115W. THIS DRY AIR LIES IN THE PATH OF ESTELLE. EASTERLY FLOW PREVAILS ACROSS THE REMAINDER OF THE DISCUSSION AREA IN THE DEEP TROPICS S OF 10N. 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 SOME CONVECTION ALONG THE ITCZ BETWEEN 133W AND 136W...AND ALSO BETWEEN 100W AND 117W. AT THE SURFACE...A RIDGE DOMINATES THE NORTHERN WATERS MAINLY N OF 18N AND W OF 115W. PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES OVER NW MEXICO IS PRODUCING DIURNALLY ENHANCED NW WINDS OF 20 KT WITHIN 120 NM OF THE COAST OF BAJA CALIFORNIA. EXPECT N TO NE WINDS OF 20 KT ACROSS THE NW WATERS MAINLY N OF 23N AND W OF 125W OVER THE NEXT COUPLE OF DAYS AS THE PRES GRADIENT CONTINUES TO TIGHTEN BETWEEN HIGH PRES LOCATED NW OF AREA AND LOWER PRES OVER THE SW CONUS AND NW MEXICO. A SURFACE TROUGH EXTENDS FROM 13N136W TO 07N137W. AN 1830 UTC HIGH RESOLUTION ASCAT PASS INDICATED NE WINDS OF 15-20 KT NW OF THE TROUGH IN A BELT FROM 13N TO 18N W OF 135W. THESE MARINE CONDITIONS WILL PERSIST NW OF THE TROUGH DURING THE NEXT 24 HOURS WITH THE TROUGH EXPECTED TO MOVE W OF THE AREA BY 48 HOURS. ITCZ DISTURBANCES CONTINUE TO PRODUCE A BELT OF SW WINDS OF 20 KT IN AN AREA FROM 08N TO 14N BETWEEN 98W AND 115W. A 1650 UTC HIGH RESOLUTION ASCAT PASS CONFIRMED THE AREA OF WINDS. THIS OVERALL WEATHER PATTERN WILL PERSIST DURING THE NEXT FEW DAYS. CROSS EQUATORIAL SW SWELLS WITH PERIODS OF 14-16 SECONDS DOMINATE THE MAJORITY OF THE FORECAST WATERS. THESE SWELLS WILL GRADUALLY DECAY INTO MON AS A NEW SWELL TRAIN CROSSES THE EQUATOR BETWEEN 105W AND 125W. $$ COBB