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Climate outlook for Water Year 2012. Nate Mantua, PhD University of Washington JISAO Climate Impacts Group November 2, 2011. Last year, mid-October: cool tropics and La Niña. IRI Forecasts from September 2010: odds favored a wet PNW fall, and cool along the coast. OND temperature.
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Climate outlook for Water Year 2012 Nate Mantua, PhD University of Washington JISAO Climate Impacts Group November 2, 2011
IRI Forecasts from September 2010:odds favored a wet PNW fall, and cool along the coast OND temperature OND precipitation http://portal.iri.columbia.edu/portal/server.pt
IRI Forecasts from September 2010:odds favored for a cool/wet PNW winter JFM temperature JFM precipitation http://portal.iri.columbia.edu/portal/server.pt
OND 2010 precip JFM 2011 precip OND 2010 temp JFM 2011 temp
Pacific Climate Outlook • forecasts centered on a weak/moderate La Niña event now through winter 2012 • PDO: cool phase sustained with help from La Niña Forecast summaries European Center 2011 2012 2011 2012
Typical US Temperature, Precipitation and Jet Stream Patterns during La Niña Winters
Major PNW windstorms favored in ENSO neutral/weak La Niña years (slide provided by Cliff Mass, UW)
Cascade pass road closures and ENSO(slide from Nick Bond, Washington State Climatologist) • No simple story with La Niña or El Niño on pass closure dates! Dec 1 Nov 1
2nd year of a back-to-back La Niña series? 1st year temp JFM OND 2nd year temp OND JFM
2nd year of a back-to-back La Niña series? 1st year precip JFM OND 2nd year precip OND JFM
IRI forecasts from October 2011 NDJ Temperature NDJ Precip http://portal.iri.columbia.edu/portal/server.pt
IRI forecasts from October 2011 JFM Temperature JFM Precip http://portal.iri.columbia.edu/portal/server.pt
NOAA/CPC U. S. Seasonal Outlooks NDJ temperature NDJ precip FMA precip FMA temperature The seasonal outlooks combine the effects of long-term trends, soil moisture, and ENSO. Issued October 20, 2011
The Bottom line • expectation for weak/moderate La Niña conditions to continue through winter and into spring tilts the odds in favor of a cool and wet fall and winter for the PNW region • Additional influences from cool phase PDO conditions should bolster these odds • 2nd of back to back La Niña winter patterns does not appreciably change this outlook; expectations for a weaker La Niña than last winter’s probably more important than the back-to-back factor