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Climatic Perspective on the fall/winter of 2004-2005

Climatic Perspective on the fall/winter of 2004-2005. Nathan Mantua, Ph.D. University of Washington Climate Impacts Group http://cses.washington.edu/cig March 21st, 2005 -- Washington Water outlook. The good news. The winter of 2004-05 has finally ended! It’s been snowing in the Cascades.

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Climatic Perspective on the fall/winter of 2004-2005

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  1. Climatic Perspective on the fall/winter of 2004-2005 Nathan Mantua, Ph.D. University of Washington Climate Impacts Group http://cses.washington.edu/cig March 21st, 2005 -- Washington Water outlook

  2. The good news • The winter of 2004-05 has finally ended! • It’s been snowing in the Cascades From the Mt Baker ski area web-cam (10 am, Sunday March 20th)

  3. outline • Where are we? • How and why did we get here? • Where do we appear to be going in the next few months?

  4. Where are we? (climatologically speaking) • In a lousy snowpack situation - current snow-water for the Washington Cascades ranges from 13% for the Cedar/Tolt/Green to 44% for the Columbia R. above the Methow

  5. How did we get here? • the low snowpack occurred largely because of warm temperatures during the periods when most of our precipitation occurred: December 6-10 and January 17-19

  6. 76% • Fall and winter storms have generally been too warm to develop this year’s snowpack 35%

  7. 73% • White-Green-Puyallup: swe-23%, pcp 53% • Cedar-Snoqualmie-Skykomish Tolt: swe-13%, pcp 64% • Baker-Skagit-Nooksack: swe-23%, pcp 77% 19%

  8. seasonal averages of precipitation and temperature are not exceptional. Most locations in Washington have received 65-80% of normal precipitation since October 1. This is considerably more than in 1977 or 2001. Temperatures also have been only about 1F above normal. Precip % of normal since Oct 1

  9. Los Angeles got almost twice as much rainfall as Seattle (~25" versus ~17") since October 1!

  10. Jet stream wind patterns Why? R • The proximate cause was a large number of days with a split jet stream around a blocking ridge located over the NW region • Was it El Niño? • Definitely not “typical” of past El Niño events Ocean temperature anomalies

  11. Oct 2004-Feb 2005 200mb ht anomalies The tropical atmosphere has been warm!

  12. Tropical SST indices

  13. Are we in a situation like the early 1990s with multiyear warmth in the western eq. Pacific?

  14. Oct-Mar 91-95 200mb ht anoms Oct-Mar 02-05 200mb ht anoms

  15. Oct-Mar 91-95 SST anoms Oct-Mar 2002-05 SST anoms

  16. \ From NCDC’s 2004 Annual Climate Report http://www.ncdc.noaa.gov

  17. What’s next? • NOAA’s Climate Prediction Center calls for increased odds for above average spring (AMJ) temperatures, and climatological odds for precipitation (forecast issued March 17th) Temperature Precipitation

  18. What’s next? (another view) • The International Research Institute for Climate Prediction (iri.columbia.edu) also predicts a tilt in the odds favoring a warm spring (AMJ)

  19. SST anomalies for the past month

  20. summary • It has been a warm and dry winter, but not of “record” extremes in either temperature or precipitation • The tropics have been very warm, yet not in a “classic” El Niño pattern • part of longer term and broader scale atmospheric warming? • Official CPC forecast calls for increased odds for a warm spring

  21. CPC forecast for July-August-September 2005 Temperature Precipitation

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