1. Climate variations in the Northwest, seasonal climate forecasting, and outlook for winter 2001-2002 Nate Mantua Climate Impacts Group University of Washington

4. A history of the PDO warm cool warm A history of ENSO 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

9. Effects of PDO and ENSO on PNW average temperature Warm ENSO, warm PDO Warm ENSO Cool ENSO Cool ENSO, cool PDO -½  ½½ ENSO neutral, cool PDO Degrees F Years classified according to http://www.atmos.washington.edu/~mantua/TABLES2.html

10. Effects of PDO and ENSO on PNW average precipitation Warm ENSO, warm PDO Warm ENSO Cool ENSO Cool ENSO, cool PDO -½  ½½ Years classified according to http://www.atmos.washington.edu/~mantua/TABLES2.html Inches

11. Warm ENSO, warm PDO Warm ENSO Cool ENSO Cool ENSO, cool PDO Annual mean: 50% higher Annual mean: 25% higher ENSO, PDO, and Chester Morse inflow

12. Summary ENSO, PDO play a modest role in winter and spring climate: zwarm ENSO, warm PDO tilt balance to above- average temperatures and below-average precipitation zcool ENSO, cool PDO tilt balance (less) toward cool wet zENSO and PDO can “cancel” each other zJan-Jun sensitive period for temp, Nov-Mar sensitive period for precipitation

13. The dry winter of 2000-2001

14. Nov 2000-Feb 2001 500mb height

15. Nov 2000-Feb 2001 temperature anomalies Degrees F

16. Nov 2000-Feb 2001 precipitation anomalies Standard deviations

17. Daily Precip: Oct 1 2000-Sep 30 2001 http://www.cpc.ncep.noaa.gov/products/global_monitoring/precipitation/northwest_1yrprec.html

19. Monitoring El Niño ENSO Observing Network of 70 buoys

23. The European Center’s ENSO Forecast Forecast SSTs in the eastern equatorial Pacific, from the European Center for Medium Range Weather Forecasting (www.ecmwf.int)

25. ENSO outlook summary zENSO remains in a near-neutral state zLeading ENSO prediction models are calling for weak El Niño sometime soon zLatest observations support the development of El Niño in next few months

26. The Pacific Decadal Oscillation

27. Global SST anomalies: Sept 23-29, 2001

28. Pacific Decadal Oscillation Update Since fall 1998, PDO index has had mostly negative values PDO Persistence has historically been a skillful forecast (correct ~75% of the time) odds favor “cool/negative PDO” for winter 2002 through August 2001

29. NDJ FMA MJJ

32. The Pineapple Express and tropical rainfall: a potential NW link to the tropical Madden-Julian Oscillation

33. Conclusions zWeak/moderate El Niño is possible for next few seasons zCPC’s forecas for PNW: climatological odds for winter, enhanced odds for a warm spring zwhat about PDO? Cool PDO conditions may favor cool/wet winter and spring yNorth Pacific Ocean situation similar to last year (but atmosphere ignored ocean last year)