Long range weather forecast - PowerPoint by Fzd4JI


									    Seasonal Climate Forecast
    October – December 2012
             (Issued: September 19, 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
 El Niño Southern Oscillation (ENSO)
   ENSO-neutral (near normal) conditions are continuing.
  However, eastern tropical Pacific Ocean sea-surface
  temperature (SST) anomalies exceed +0.5°C.
   About half of the statistical models show ENSO-neutral
  conditions lasting through 2012, but almost all of the
  dynamic models predict El Niño (warmer than normal
  SSTs) conditions this autumn…lasting into this winter.
   An “El Niño Watch” has been issued by the Climate
  Prediction Center (CPC). The official CPC forecast is for
  weak El Niño conditions to develop this fall and continue
  into this winter.
  Courtesy: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory
                  Tropical Pacific Ocean
   Animated (in PowerPoint 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
             SOI* Values For the Top "Analog Years"
                  and the Current Year (2011-12)
                 (2008-09; 2000-01; 1950-51)


                                               La Niña
      1.5                                                                   2011-12
      1.0                                                                   2008-09

      0.5                                                                   1950-51



                                  El Niño
             J F M A M J J A S O N D J F M A M J J A S O N D

 *For SOI explanation see: http://oregon.gov/ODA/NRD/docs/pdf/forecast_method.pdf
                         ENSO Indices
             ONI* Values For the Top "Analog Years"
                  and the Current Year (2011-12)
                (2008-09; 2000-01; 1950-51)

                                          El Niño

      0.5                                                                   2011-12



                     La Niña

                            3-Month Running Mean
 *For ONI explanation see: http://oregon.gov/ODA/NRD/docs/pdf/forecast_method.pdf
         ENSO Predictive Models
Nearly all dynamic models predict “El Niño” development

                                               El Niño

                                               La Niña

   Courtesy: http://iri.columbia.edu/climate/ENSO/currentinfo/SST_table.html
             ENSO Predictive Models
The CPC/IRI consensus forecast favors “El Niño” development

              El Niño conditions are most likely this autumn
                           through early winter

   Courtesy: http://portal.iri.columbia.edu/portal/server.pt?open=512&objID=945&mode=2
              October 2012 Forecast
        Temperatures                      Precipitation

   Analog years consistently show a rather dramatic switch from
    a relatively warm and dry summer to cooler and wetter than
    average weather in October.
            November 2012 Forecast
       Temperatures                     Precipitation

   Near to slightly above normal temperatures.
   Precipitation near normal.
   Mountain snowpack likely beginning by Thanksgiving.
             December 2012 Forecast
        Temperatures                       Precipitation

   Decreased forecast confidence due to diverse weather during
    the analog years (some with significant cold episodes).
   Most likely colder than normal with near normal precipitation.
            Oct. – Dec. 2012 Forecast
        Temperatures                      Precipitation

   After a relatively warm and dry summer, analog years suggest
    a transition to cool and wet (stormy) autumn weather.
   Heightened chances of cold/(valley snow) in December.
             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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