000 AXPZ20 KNHC 012153 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC THU OCT 01 2009 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 2145 UTC. ...SPECIAL FEATURE... TROPICAL DEPRESSION EIGHTEEN-E CONTINUES TO ORGANIZE AND HAS NOW BECOME TROPICAL STORM OLAF...THE FIFTEENTH NAMED STORM IN THE EAST PACIFIC BASIN FOR THE 2009 SEASON. OLAF WAS CENTERED NEAR 19.4N 117.8W AT 01/2100 UTC OR ABOUT 455 NM...905 KM... WEST-SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA WITH MAXIMUM SUSTAINED WINDS OF 35 KT WITH GUSTS TO 45 KT. THE DEPRESSION WAS MOVING WEST-NORTHWEST OR 300 DEG AT 5 KT WITH AN ESTIMATED MINIMUM CENTRAL PRESSURE OF 1002 MB. A 1318 UTC HIGH RESOLUTION QUIKSCAT PASS INDICATED OLAF POSSESSED A LARGE OUTER ENVELOPE OF 20-25 KT WINDS WHICH EXTENDED OUTWARD UP TO 360 NM IN THE E SEMICIRCLE. THIS SAME PASS ALSO INDICATED THE WIND FIELD IN THE W SEMICIRCLE WAS MERGING WITH A LARGER AREA OF MODERATE TO FRESH NE TRADES OVER THE PACIFIC. CONVECTION WISE...SCATTERED TO NUMEROUS STRONG CONVECTION WAS NOTED WITHIN 90 NM OF THE CENTER MAINLY IN THE E SEMICIRCLE. ADDITIONAL SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS NOTED WITHIN 210 NM IN THE E AND 120 NM IN THE W SEMICIRCLES AND WELL E OF THE CENTER WITHIN 60 NM OF THE COAST OF BAJA CALIFORNIA. THE WINDOW FOR ADDITIONAL STRENGTHENING IS NARROWING AS WATER VAPOR IMAGERY INDICATED MODERATE TO STRONG SOUTHERLY SHEAR NOT TOO FAR W OF THE TROPICAL CYCLONE. ADDITIONAL INFORMATION CAN BE FOUND UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC. ...TROPICAL WAVE... TROPICAL WAVE NOTED EARLIER FROM 08N TO 16N ALONG 107W HAS BECOME ABSORBED INTO THE LARGE CIRCULATION OF TROPICAL STORM OLAF. CURRENTLY...AN AREA OF SCATTERED MODERATE CONVECTION WAS NOTED IN AN AREA FROM 15N TO 19N BETWEEN 107W AND 111W. ...ITCZ... AXIS IS ALONG 07N78W TO 08N90W TO 08N101W TO 15N115W...THEN RESUMES AT 14N120W TO 11N127W TO 09N140W. SCATTERED MODERATE TO STRONG FROM 05N TO 09N BETWEEN 79W AND 83W. SCATTERED MODERATE ISOLATED STRONG WITHIN 180 NM S OF THE AXIS BETWEEN 108W AND 112W...180 NM N OF THE AXIS BETWEEN 131W AND 136W AND WITHIN 120 NM N OF THE AXIS BETWEEN 125W AND 129W. ...DISCUSSION... RATHER AMPLIFIED PATTERN IN PLACE S OF 30N WITH A SHARP SHEAR AXIS EXTENDING FROM SOUTHERN CALIFORNIA WESTWARD THROUGH 32N127W TO A CYCLONIC CIRCULATION NEAR 29N141W. A MORE SIGNIFICANT TROUGH CONTINUED SOUTH-SOUTHWESTWARD FROM THE CIRCULATION TO A BASE NEAR 14N144W. SATELLITE DERIVED WINDS INDICATED A 70-95 KT JETSTREAM SE OF THE TROUGH WHICH EXTENDED FROM 14N140W 22N135W TO NORTHERN BAJA CALIFORNIA. MODERATE TO STRONG SUBSIDENCE WITH DRY STABLE AIR IN THE MIDDLE AND UPPER LEVELS OF THE ATMOSPHERE WAS NOTED WITHIN THE SHEAR AXIS AND SWEEPING AROUND THE BACKSIDE OF TROUGH N OF 13N W OF 138W. DOWNSTREAM UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR 22N108W...WITH RIDGE N TO THE NORTHERN COAST OF THE BAJA PENINSULA. UPPER LEVEL DIFFLUENT FLOW SW OF THE ANTICYCLONIC CIRCULATION IS ENHANCING CONVECTIVE ACTIVITY IN THE VICINITY OF TROPICAL STORM OLAF. AN INVERTED TROUGH IN THE DEEP TROPICS WITH AXIS FROM THE EQUATOR AT 98W TO 10N90W WAS NEARLY STATIONARY. MODERATE TO STRONG SUBSIDENCE IS WITH THE TROUGH S OF 7N E OF 100W. AT THE SURFACE... STRONG RIDGE OF HIGH PRES EXTENDED SE FROM A 1038 MB HIGH NEAR 40N143W AND COVERED THE DISCUSSION AREA N OF 20N W OF 115W. THE RIDGE COMBINED WITH THE LOWER PRESSURES IN THE TROPICS AND IN THE VICINITY OF TROPICAL STORM OLAF HAS RESULTED IN A LARGE AREA OF NE TRADES OF 20 TO 25 KT GENERALLY N OF 20N AND W OF 120W. AS NOTED ABOVE THE WIND FIELD ASSOCIATED WITH OLAF IN THE W SEMICIRCLE HAS MERGED INTO THE LARGER AREA OF TRADES WITH A LARGE AREA OF 10 TO 13 FT SEAS NOTED. $$ COBB