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Climate recap and outlook. Nate Mantua, PhD University of Washington Center for Science in the Earth System - Climate Impacts Group Vancouver, WA October 2, 2008. The CSES - Climate Impacts Group. http://cses.washington.edu/cig/.
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Climate recap and outlook Nate Mantua, PhD University of Washington Center for Science in the Earth System - Climate Impacts Group Vancouver, WA October 2, 2008
The CSES - Climate Impacts Group http://cses.washington.edu/cig/ • Goal: help the Pacific Northwest become more resilient to climate variations and climate change • Supported by NOAA Climate Program Office as part of the Regional Integrated Science and Assessments (RISA) program
Accumulated Precip for the past year Source: http://www.cpc.ncep.noaa.gov/products/global_monitoring/precipitation/northwest_1yrprec.shtml
Accumulated Precip for the past year December 3rd storm Source: http://www.cpc.ncep.noaa.gov/products/global_monitoring/precipitation/northwest_1yrprec.shtml
Chehalis River Flooding at Centralia, WA Seattle PI, Dec 5, 2007 Seattle Times, Dec 17, 2007
Daily Temperatures -0.67ºC
A big snow year for the Cascades Mark Stoelinga at his Skykomish Cabin January 31, 2008 http://www.komonews.com/news/15089626.html Elev 3500ft
Summer ocean conditions upwelling downwelling
Coastal Upwelling • Area below (above) black line indicates climatological upwelling (downwelling) season. • Climatologically upwelling season progresses from March to July along the west coast of North America from 36ºN to 57ºN. • Figures provided by Yan Xue, NOAA NCEP Winter downwelling was weak; upwelling was strong in April, May, and June, but weak in July-August
Coastal ocean temperatures were cold from winter through July
Oct 2007-June 2008 SST anomalies: La Niña and a cool phase of the PDO
Land and Ocean temperature anomaly was +0.72°C (1901-2000 climatology), 8th warmest in 129 years
Pacific Climate Outlook Summary from Oct 2007 • forecasts rated La Niña as most likely situation for 2007-08 • PDO: Transiting to cool phase as La Niña fades Forecast summaries European Center 2007 2008 2007 2008
Typical winter climate pattern jet stream during past La Niña winters
Last Year’s forecast: Wet Autumn and winter, Equal Chances on Temperature Temperature Precip OND OND DJF DJF
Blame the circulation pattern • observed 500mb height anomalies from Dec 2007-June 2008 shows a persistent region of high heights in the Gulf of Alaska and low heights over south-central Canada … L H
Blame the circulation pattern • At left is a “composite” for the last 8 La Niña periods … a close match to 2007-2008 pattern
La Nada • Tropical ocean temperatures have generally returned to long-term averages
Equatorial subsurface ocean temperature anomaly • Colder than average waters in the east indicate a shallow thermocline, favoring additional cooling in the near term
The latest ENSO forecasts See http://iri.columbia.edu/climate/ENSO European Center Forecast summary
PDO forecast: drifting toward neutral territory -- index has been negative since last September From June-July-August 2008 initial conditions http://www.cdc.noaa.gov/forecast1/for1pdo.html
Another factor in seasonal forecasts PNW December-January-February temperatures
30-day climate forecast: expect a cool-wet beginning to fall (from Sept 30, 2008) See http://www.cpc.ncep.noaa.gov
CPC Forecasts from Sept 18, 2008 precipitation temperature
The Bottom line • expectation for ENSO-neutral conditions, combined with recent trends, favors “Equal Chances” for fall-winter precipitation and a small increase in the odds for warmer than average temperatures • ENSO neutral and La Niña years tend to favor major flood events • Additional influence from PDO might offset another factor… • Persistent warming trends See http://www.cpc.ncep.noaa.gov
Sept 30 estimated soil moisture percentiles • Courtesy of Andy Wood, University of Washington, data and images are available at http://www.hydro.washington.edu/forecast/monitor
Daily Temperatures -0.67ºC +0.03ºC -0.64ºC