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Winter Forecast 2011-12 October 29,
2011
Pete Parsons, ODF Meteorologist503-945-7448 [email protected]
oregon.gov/oda/nrd/weather.shtml#weather_forecasts
PWODT/OMSI Exclusive Presentation!
Best Prediction Since 1996
Winter Prediction 2010-11…Packers will
overcome injuries and win the Super Bowl!
Back to the Weather!
November – January 2010-11 (Forecast Issued
October 16, 2010)Forecast Precipitation Actual Precipitation
Data courtesy of the National Climatic Data Center (NCDC)
November – January 2010-11 (Forecast Issued
October 16, 2010)Forecast Temperatures Actual Temperatures
Data courtesy of the National Climatic Data Center (NCDC)
December – February 2010-11 (Forecast Issued
October 16, 2010)Forecast Precipitation Actual Precipitation
Data courtesy of the National Climatic Data Center (NCDC)
December – February 2010-11 (Forecast Issued
October 16, 2010)Forecast Temperatures Actual Temperatures
Data courtesy of the National Climatic Data Center (NCDC)
Winter 2010-11 Forecast
Well above normal precipitation.
Near normal temperatures.
Above average mountain snow.
One or more of the following in December and/or January: coastal windstorm(s); Arctic outbreak; valley snow/ice; flooding.
Typical ENSO Patterns
WarmEvent
ColdEvent
PWODT Seasonal Climate Forecasting
MethodUse the SOI and ONI to
Identify Past Years With Similar Tropical Pacific Ocean Sea-Surface Temperatures.
Use Historical Data From Those Years to Make General Seasonal Predictions.
No Corrections are Made for Changes in Global Climate…Creating Error.
SOI Based On Pressure Anomalies of
Two Sites
TahitiDarwin
La NiñaEvents
El NiñoEvents
RepeatingPattern?
ONI Based on SST Departures in Niño
3.4
ONI Based on SST Departures in Niño
3.4
La NiñaEvents
El NiñoEvents
ONI Based on SST Departures in Niño
3.4RepeatingPattern?
El Niño Modoki Feb. 2010
La Niña Feb. 2011
ENSO-Neutral July 2011
August - October, 2011
La Niña Oct. 2011
ENSO-Neutral Oct. 2008
La Niña Returned? Dec. 2008
La Niña Oct. 2011
Winter Forecast 2011-12
November - January2011-12 Forecast
Precipitation Temperatures
December - February2011-12 Forecast
Precipitation Temperatures
Winter 2011-12 Forecast
Above average temperatures early. Bonus if ski areas can open by Thanksgiving.
Turning stormy in December and January with another cold February.
Cold periods will have a better chance of being accompanied by snow this winter.
Most mountain snowpacks should be above normal by late January - February.
Winter 2011-12 Snowlights
Average Portland snowfall 4.5”
Analog average snowfall 7.5”
Above average snowfall likely for the Willamette Valley.
Watch out for freezing rain.
Winter’s Big Question?
Could We See aRepeat of 2008-09?Or Worse…?
Winter Forecast 2011-12 October 29,
2011
Pete Parsons, ODF Meteorologist503-945-7448 [email protected]
oregon.gov/oda/nrd/weather.shtml#weather_forecasts
PWODT/OMSI Exclusive Presentation!
