Seasonal Climate Forecast Dec – Feb (Issued: November 15, 2012) This Product is Published by the Oregon Department of Agriculture (ODA), in Cooperation with the Oregon Department of Forestry (ODF). Contact: ODF Meteorologist Pete Parsons at Get related Seasonal Climate Forecast information at This Product is Published by the Oregon Department of Agriculture (ODA), in Cooperation with the Oregon Department of Forestry (ODF). Contact: ODF Meteorologist Pete Parsons at Get related Seasonal Climate Forecast information at

El Niño Southern Oscillation (ENSO) ENSO-neutral (near normal) conditions are continuing. However, central and western tropical Pacific Ocean sea- surface temperatures (SSTs) remain above normal. ENSO-neutral (near normal) conditions are continuing. However, central and western tropical Pacific Ocean sea- surface temperatures (SSTs) remain above normal. A full-fledged weak El Niño event is becoming less likely this winter, with the most recent trends in the opposite direction (towards ENSO-neutral conditions). A full-fledged weak El Niño event is becoming less likely this winter, with the most recent trends in the opposite direction (towards ENSO-neutral conditions). The previously issued El Niño Watch has been discontinued by the Climate Prediction Center (CPC). The previously issued El Niño Watch has been discontinued by the Climate Prediction Center (CPC). The official CPC forecast is now for ENSO-neutral conditions to continue through this winter. The official CPC forecast is now for ENSO-neutral conditions to continue through this winter. Courtesy:

Tropical Pacific Ocean Animated (in PowerPoint only) SSTs (top) / Anomalies (bottom) Courtesy:

Tropical Pacific Ocean ENSO Neutral conditions are continuing… Courtesy:

ENSO Indices El Niño La Niña ( ; ; )

ENSO Indices El Niño La Niña ( ; ; )

ENSO Predictive Models Most models predict continued slow cooling in the central tropical Pacific Ocean Courtesy: La Niña El Niño ENSO-neutral conditions are most likely through mid-2013

ENSO Predictive Models The CPC/IRI consensus forecast Courtesy: ENSO-neutral conditions are most likely through mid-2013

December 2012 Forecast TemperaturesPrecipitation Stormy periods likely. Cooler than normal with near to above normal precipitation. Increased chance of Arctic outbreaks late in the month. Stormy periods likely. Cooler than normal with near to above normal precipitation. Increased chance of Arctic outbreaks late in the month. Diverse weather during the analog years (some mild and stormy and others with significant cold episodes) lowers forecast confidence. Diverse weather during the analog years (some mild and stormy and others with significant cold episodes) lowers forecast confidence.

January 2013 Forecast TemperaturesPrecipitation ENSO-neutral conditions favor stormy and mild periods alternating with cold and dry stretches (often with Arctic outbreaks and valley snow). ENSO-neutral conditions favor stormy and mild periods alternating with cold and dry stretches (often with Arctic outbreaks and valley snow). Overall temperatures will depend on the severity of any cold snaps. Overall temperatures will depend on the severity of any cold snaps. Diverse weather during the analog years lowers forecast confidence. Diverse weather during the analog years lowers forecast confidence.

February 2013 Forecast TemperaturesPrecipitation Seasonal temperatures with below normal precipitation. Seasonal temperatures with below normal precipitation. Most analog years had El Niño episodes, which would typically yield a mild and dry February. However, ENSO-neutral conditions are likely this year, so precipitation totals may be closer to normal than indicated. Most analog years had El Niño episodes, which would typically yield a mild and dry February. However, ENSO-neutral conditions are likely this year, so precipitation totals may be closer to normal than indicated.

Dec – Feb Forecast TemperaturesPrecipitation Mild and stormy periods alternating with cool and drier periods. Severity of any cold snaps will strongly influence overall departures. Mild and stormy periods alternating with cool and drier periods. Severity of any cold snaps will strongly influence overall departures. ENSO-neutral conditions favor Arctic intrusions and valley snow events, mainly from mid-December through January. ENSO-neutral conditions favor Arctic intrusions and valley snow events, mainly from mid-December through January.

Winter Highlights There are no excellent analog matches for this winter (looking back over the past 100+ years). There are no excellent analog matches for this winter (looking back over the past 100+ years). It is rare to have back-to-back La Niña winters (the past two) followed by ENSO-neutral conditions (forecast for this winter). This year is also unique due to the recent decay of what appeared to be a developing El Niño episode. It is rare to have back-to-back La Niña winters (the past two) followed by ENSO-neutral conditions (forecast for this winter). This year is also unique due to the recent decay of what appeared to be a developing El Niño episode. ENSO-neutral winters tend to produce stormy and mild periods alternating with cool and dry periods (often Arctic outbreaks). The transitions can bring valley snow & ice. ENSO-neutral winters tend to produce stormy and mild periods alternating with cool and dry periods (often Arctic outbreaks). The transitions can bring valley snow & ice. The favored ENSO-neutral period for Arctic outbreaks and valley snow events is from mid-December through January. The favored ENSO-neutral period for Arctic outbreaks and valley snow events is from mid-December through January.

Updated Monthly (around the 20 th ) Contact: Pete Parsons, ODF Meteorologist ODA Production support from Diana Walker and Mary Jane Schaffer Contact: Pete Parsons, ODF Meteorologist ODA Production support from Diana Walker and Mary Jane Schaffer Your Feedback is Welcome