Seasonal Climate Forecast Dec 2012 Feb 2013 Issued
Seasonal Climate Forecast Dec. 2012 – Feb. 2013 (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 503 -945 -7448 pparsons@odf. state. or. us Get related Seasonal Climate Forecast information at http: //cms. oregon. gov/ODA/NRD/Pages/weather. aspx
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. n 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). n. The previously issued “El Niño Watch” has been discontinued by the Climate Prediction Center (CPC). Courtesy: http: //www. cpc. ncep. noaa. gov/products/analysis_monitoring/enso_advisory n The official CPC forecast is now for ENSOhttp: //www. cpc. ncep. noaa. gov/products/analysis_monitoring/enso_advisory/ensodisc. html n
Tropical Pacific Ocean Animated (in Power. Point only) SSTs (top) / Anomalies (bottom) Courtesy: http: //www. cpc. ncep. noaa. gov/products/analysis_monitoring/enso_update/sstanim. shtml
Tropical Pacific Ocean “ENSO Neutral” conditions are continuing… Courtesy: http: //www. cpc. ncep. noaa. gov/products/analysis_monitoring/enso_update/sstweek_c. gif
ENSO Indices (2008 -09; 2000 -01; 1950 -51) La Niña El Niño
ENSO Indices (2008 -09; 2000 -01; 1950 -51) El Niño La Niña
ENSO Predictive Models Most models predict continued slow cooling in the central tropical Pacific Ocean El Niño ENSO-neutral conditions are most likely through mid-2013 La Niña Courtesy: http: //iri. columbia. edu/climate/ENSO/currentinfo/SST_table. html
ENSO Predictive Models The CPC/IRI consensus forecast ENSO-neutral conditions are most likely through mid-2013 Courtesy: http: //portal. iri. columbia. edu/portal/server. pt? open=512&obj. ID=945&mode=2
December 2012 Forecast Temperatures n n Precipitation 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.
January 2013 Forecast Temperatures n n Precipitation 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.
February 2013 Forecast Temperatures n n 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
Dec. 2012 – Feb. 2013 Forecast Temperatures n n Precipitation 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.
Winter 2012 -13 Highlights n n 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. 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
Updated Monthly (around the 20 th) Your Feedback is Welcome Contact: Pete Parsons, ODF Meteorologist 503 -945 -7448 pparsons@odf. state. or. us ODA Production support from Diana Walker and Mary Jane Schaffer
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