1 / 16

Seasonal Climate Forecast Dec. 2014 – Feb. 2015 (Issued: November 24, 2014)

Seasonal Climate Forecast Dec. 2014 – Feb. 2015 (Issued: November 24, 2014). 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

channing-marcel
Télécharger la présentation

Seasonal Climate Forecast Dec. 2014 – Feb. 2015 (Issued: November 24, 2014)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Seasonal Climate ForecastDec. 2014 – Feb. 2015(Issued: November 24, 2014) 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 or peter.gj.parsons@oregon.gov Get related Seasonal Climate Forecast information at: http://www.oregon.gov/ODA/programs/NaturalResources/Pages/Weather.aspx

  2. Forecast Method Notes… • Analog years were obtained by tracking and comparing a variety of indices over the past several years (see Forecasting Methods). Priority was given to years from a “Cool Phase”period of the Pacific Decadal Oscillation (PDO) with sea-surface temperatures (SSTs) most closely matching the current SSTs in the equatorial Pacific Ocean. • The analog years (2009-10; 1968-69; 1951-52) used to create this forecast are all from “Cool Phase”periods of the “PDO” and are unchanged from last month. • A moderate-strength El Niño developed during the winter in each of the top analog years.

  3. El Niño Southern Oscillation (ENSO)Current Status and Forecast • ENSO-neutral (average) conditions continue across the equatorial Pacific Ocean, although sea-surface temperatures (SSTs) are above weak El Niño thresholds. • The Climate Prediction Center’s (CPC) confidence in the development of a full-fledged El Niño…lasting into the spring of 2015, has dropped but is still above 50%. • The “analog years” used in this forecast support the development of a moderate-strength El Niño this winter. • A weak or moderate-strength El Niño is most likely for this coming winter, but continued warm ENSO-neutral conditions is also possible. http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

  4. Tropical Pacific OceanAnimated (in PowerPoint only) SSTs (top) / Anomalies (bottom) Courtesy: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/sstanim.shtml

  5. Tropical Pacific OceanSSTs have warmed into the range of a weak El Niño Courtesy: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/sstweek_c.gif

  6. ENSO Indices (2008-09;1967-68; 1950-51) La Niña ENSO-Neutral El Niño

  7. ENSO Indices (2008-09;1967-68; 1950-51) El Niño developed, by late-autumn, in each of the top 3 analog years. El Niño ENSO-Neutral El Niño may develop this winter. La Niña conditions developed, during the winter, in 1 of the top 3 analog years. La Niña

  8. ENSO Predictive ModelsComputer models favor a weak El Niño this winter Model forecasts favor ENSO-neutral conditions through spring 2014; followed by El Niño development. El Niño ENSO-neutral La Niña Courtesy: http://iri.columbia.edu/climate/ENSO/currentinfo/SST_table.html

  9. December 2014 Forecast Temperatures Precipitation • Consensus among the analog years is for below average temperatures. • Two of the top analog years (1951 & 1968) were very stormy with above average precipitation, but the third year (2009) was quite dry. • Heavy valley snow in December 1968 but not in 1951 nor in 2009.

  10. January 2015 Forecast Temperatures Precipitation • Extreme variation of weather among the analog years…ranging from very cold and wet (1969) to very mild and somewhat dry (2010). • Graphics are skewed cold and wet by the extreme conditions of 1969, but a mild and dry January is more typical with El Niño.

  11. February 2015 Forecast Temperatures Precipitation • Extreme cold is unlikely, but overall temperatures may end up below average (not typical of El Niño). • Precipitation near or below average (more typical of El Niño).

  12. Dec. 2014 – Feb. 2015 Forecast Temperatures Precipitation • Tremendous variation among analog years for December and January increases forecast uncertainty. A “classic” El Niño produces warmer and drier than average weather, but the opposite extremes can occur…

  13. Dec. 2014 – Feb. 2015 Highlights • A weak or moderate El Niño is likely this winter, which commonly produces cool and stormy conditions in late-autumn, but relatively mild and dry weather in mid-winter. • Mountain snowfall (relative to average) is typically greater across southern Oregon than across northern Oregon. • However, there are other possibilities… • In stark contrast to the current Climate Prediction Center (CPC) Forecasts, the analog method used here shows that extremely cold and wet weather can’t be ruled out for December and January. • Dec. 1968 – Jan. 1969, (one of the top analog years) produced multiple Arctic outbreaks with heavy snowfall across much of the state, especially for northern Oregon. • Extremely cold weather becomes unlikely after January, but generally cool temperatures may prevail into February.

  14. Some Helpful Resources • CPC Official US Three-Month Forecasts (Graphics): http://www.cpc.ncep.noaa.gov/products/predictions/long_range/seasonal.php?lead=01 • CPC US 30-Day & 90-Day Forecasts (Discussions): http://www.cpc.ncep.noaa.gov/products/predictions/long_range/fxus07.html • CPC Weekly & Monthly ENSO Discussions: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory • Australian Government Weekly Tropical Climate Note: http://www.bom.gov.au/climate/tropnote/tropnote.shtml • Australian Government ENSO Wrap-Up: http://www.bom.gov.au/climate/enso • IRI ENSO Quick Look: http://portal.iri.columbia.edu/portal/server.pt?open=512&objID=945&mode=2 • NRCS Western Snowpack Data & Water Supply Forecast: http://www.wcc.nrcs.usda.gov/cgibin/westsnowsummary.pl

  15. Updated Monthly(around the 20th) Your Feedback is Welcome Contact: Pete Parsons, ODF Meteorologist at 503-945-7448 or peter.gj.parsons@oregon.gov ODA Production support from Diana Walker and Andy Zimmerman

More Related