000 AXPZ20 KNHC 021009 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC FRI OCT 02 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 0930 UTC. ...SPECIAL FEATURE... TROPICAL STORM OLAF...WAS CENTERED NEAR 22.0N 117.5W AT 02/0900 UTC OR ABOUT 420 NM...778 KM...WEST-SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA...WITH MAXIMUM SUSTAINED WINDS OF 40 KT WITH GUSTS TO 50 KT. OLAF WAS MOVING N OR 360 DEG AT 10 KT WITH AN ESTIMATED MINIMUM CENTRAL PRESSURE OF 1000 MB. A LARGE CIRCULAR CLUSTER OF STRONG CONVECTION HAS DEVELOPED ACROSS THE N SEMICIRCLE OF OLAF IN THE PAST 6 HOURS...GIVING THE APPEARANCE OF A CLASSIC CDO PATTERN. HOWEVER...MICROWAVE IMAGERY CONTINUES TO INDICATE THAT THE LOW LEVEL CENTER REMAINS ALONG THE SOUTHERN SIDE OF THIS CORE OF DEEP CONVECTION...WHICH EXTENDS OUT TO 180 NM FROM THE CENTER. AN ELONGATED LOW LEVEL TROUGH CONTINUES TO EXTEND FROM THE S FLANKS OF OLAF...SW INTO THE ITCZ...YIELDING A VERY LONG FETCH OF SW TO S WINDS TO THE S AND SE OF OLAF. THE WINDOW OF OPPORTUNITY FOR ADDITIONAL STRENGTHENING IS QUICKLY NARROWING AS WATER VAPOR IMAGERY INDICATED MODERATE TO STRONG SOUTHWESTERLY SHEAR ASSOCIATED WITH AN APPROACHING UPPER TROUGH NOT TOO FAR W OF THE TROPICAL CYCLONE. OLAF IS PERSIST AT ITS CURRENT INTENSITY...WITH SOME SLIGHT CHANGE FOR MINIMAL STRENGTHENING STILL POSSIBLE IN THE NEXT 6-12 HOURS...BEFORE IT BEGINS TO WEAKEN SATURDAY. ADDITIONAL INFORMATION CAN BE FOUND UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ23 KNHC. ...ITCZ... AXIS WAS CENTERED ALONG 09N78W TO 14N106W TO 18N112W THEN RESUMES AT 17N120W TO 12N128W TO 12N140W. SCATTERED MODERATE TO STRONG N OF AXIS TO COAST E OF 87W. SCATTERED MODERATE TO STRONG WITHIN 180 NM S OF THE AXIS W OF 127W. ISOLATED MODERATE TO STRONG WITHIN 180 NM OF THE AXIS BETWEEN 87W AND 102W. ...DISCUSSION... RATHER AMPLIFIED PATTERN IN PLACE S OF 30N WITH A SHARP SHEAR AXIS EXTENDING FROM SOUTHERN CALIFORNIA WESTWARD TO A CYCLONIC CIRCULATION JUST W OF THE AREA NEAR 29N140W. A MORE SIGNIFICANT TROUGH CONTINUED SSW FROM THE CIRCULATION TO A BASE NEAR 13N146W. SATELLITE DERIVED WINDS INDICATED A 70-95 KT JET SE OF THE TROUGH WHICH EXTENDED FROM 14N140W TO 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...AN UPPER LEVEL BROAD BLOCKING ANTICYCLONIC CIRCULATION IS CENTERED NEAR 22N112W...WITH RIDGE N TO THE NORTHERN COAST OF THE BAJA PENINSULA. THIS SAME AREA OF ANTICYCLONIC FLOW IS ALSO SUPPORTING OLAF'S DEEPENING CONVECTION. 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 1035 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 20-25 KT W OF A LINE FROM 30N116W TO 20N125W TO 14N140W...EXCEPT FROM 18N-27N W OF 134W WHERE NE WINDS OF 25-30 KT WERE NOTED. 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 8-13 FT SEAS NOTED. SEAS OVER THE FAR SRN WATERS S OF ABOUT 8N ARE UP TO 9 OR 10 FT DUE TO LONG PERIOD SRN HEMISPHERIC SWELLS. THESE CONDITIONS ARE FORECAST BY WAVE MODEL GUIDANCE TO GRADUALLY BECOME DIFFUSE THROUGH THE NEXT 48 HOURS OR SHORTLY THEREAFTER. $$ STRIPLING