000 AXPZ20 KNHC 191554 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC MON OCT 19 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC. ...SPECIAL FEATURE... EXTREMELY DANGEROUS CATEGORY THREE HURRICANE RICK AT 17.8N 111.6W AT 19/1500 UTC OR ABOUT 325 NM S OF TIP OF BAJA CALIFORNIA MOVING NW AT 8 KT. ESTIMATED MINIMUM CENTRAL PRES 958 MB. MAXIMUM SUSTAINED WINDS HAVE DECREASED TO NEAR 100 KT WITH HIGHER GUSTS. ALTHOUGH RICK INTENSITY HAS PEAKED AND IS FORECAST TO WEAKEN FURTHER AS IT ENCOUNTERS STRONGER UPPER LEVEL SHEAR AND APPROACHES LAND MASS IN SOUTHERN BAJA PENINSULA IT IS EXPECTED TO REMAIN A VERY DANGEROUS SYSTEM WITH HIGH DESTRUCTION POTENTIAL. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE ALONG 86W N OF 02N HAS MODERATE EASTERLY SHEAR ALOFT PREVENTING IT FROM ANY SIGNIFICANT STRENGTHENING. THESE CONDITIONS BECOME LESS ADVERSE AS WAVE MOVES W BUT ANY INTENSIFICATION SHOULD BE BEYOND FORECAST PERIOD. SCATTERED MODERATE CONVECTION REMAINS E OF WAVE AXIS FROM 07N-09N. WEAK TROPICAL WAVE ALONG 126W FROM 06N TO 16N MOVING W AT 15 KT. ALTHOUGH CONDITIONS ALOFT REMAIN SLIGHTLY FAVORABLE FOR INTENSIFICATION...WAVE ASSOCIATED CONVECTION REMAINS MINIMAL AND LITTLE CHANGE IS EXPECTED. ...ITCZ... AXIS ALONG 09N85W TO 07N96W TO 12N103W TO 08N118W TO 12N140W. SCATTERED MODERATE TO STRONG CONVECTION WITHIN 120 NM OF AXIS 80W-89W. SCATTERED MODERATE CONVECTION WITHIN 120 NM OF AXIS 111W-118W. ...DISCUSSION... MOSTLY QUASI-ZONAL W FLOW IS N OF 20N AS WEAK UPPER LEVEL TROUGH LIES FROM 30N120W TO 24N140W. WELL DEFINED ANTICYCLONE NEAR 10N116W PREVENTS TROUGH FROM DIGGING MUCH FURTHER S. SECOND ANTICYCLONE OVER MAINLAND MEXICO HELPS IN STEERING HURRICANE RICK INTO WEAKNESS BETWEEN BOTH ANTICYCLONIC CENTERS. AT THE SURFACE... HIGH PRES CENTER 1024 MB WITH RIDGE ALONG 29N MAINTAINS GOOD HOLD OVER MOST OF E PAC N OF 20N WITH FRESH N TO NE BREEZE AS HURRICANE RICK TURNS NE INTO MEXICO. MODERATE BREEZE ALONG SOUTHERN PERIPHERY OF RIDGE MAKES NE TRADES W OF 133W. MODERATE NW SWELL AFFECT EXTREME NW CORNER OF BASIN. HEALTHY COLD FRONT INCHES INTO NW CORNER OF E PAC FORCING HIGH PRES E AND SKIRTING NORTHERN BORDER OF BASIN WITH FRESH BREEZE QUICKLY DIMINISHING AS FRONT LIFTS NORTHEASTWARD BUT LEAVING LARGE LONG PERIOD SWELLS IN ITS WAKE. GALE FORCE N TO NE WINDS S AND SW OF GULF OF TEHUANTEPEC RAPIDLY DIMINISHING BELOW GALE FORCE WITHIN 24 HOURS BUT STILL REMAIN AS A STRONG BREEZE FOR OVER 48 HOURS. $$ WALLY BARNES