CPC Forecasts: Current and Future Methods and Requirements

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CPC Forecasts Current and FutureMethods and
Requirements

• Ed OLenic
• NOAA-NWS-Climate Prediction Center
• Camp Springs, Maryland
• ed.olenic_at_noaa.gov
• 301-763-8000, ext 7528
•  

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Summary

• CPC long-lead seasonal outlooks are produced
  using, in order of perceived reliability
• - ENSO composites, trend, soil moisture and
  dynamical models (DMs) and statistical models.
• Frequent model changes hamper perceived
  reliability of DMs.
• Lack of convincing information about model biases
  reduces reliability of DM forecasts.
• Weather/climate impacts of AO, MJO, PDO are
  known.
• Prediction of AO, MJO, PDO is not yet possible.
• DMs cannot yet predict subtle differences among
  ENSOs.
• Stratospheric annular mode (SAM) is a link to AO
  prediction.
• DMs ability to predict SAM is unknown/doubtful.
• Relationship of Indian Ocean to predictable
  signals is unclear.
• Relationship of QBO, Southern Hemisphere
  mid-latitude circulations to predictable signals
  is unclear.

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WEATHER vs. CLIMATE
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Climate Prediction Center Forecast System
Schematic
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Forecast Process Schematic
Recent observations
Historical observations
Dynamical Model Forecasts
Verifications/Statistical tools Downscaling,
Analogs, Composites
Web pages, automated databases
Forecaster-created or automated products
Dissemination to public
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TOOLS VS SIGNALS
TOOLS VS SIGNALS ENSO STRONG ENSO MODER-ATE ENSO WEAK- NEUTRAL PDO AO MJO STRAT ANNLR MODE QBO
COMPOSITES o o o ? o o ? ?
TREND o o o ? ? ? ? ?
COUPLED AGCM o o o ? ? ? ? ?
STATISTICAL TOOLS- CCA, REGRESSION o o o ? ? ? ? ?
SOIL MOISTURE SUMMER o o o ? ? ? ? ?




TOOL RELIABILITY o 70-100 o 30-70
o lt 30
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Forecast tools page
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Forecast tools web page
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CMP T Forecasts
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CMP NDJ 2000-01 T Verification
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CCA 0.5 Mo lead NDJ T Outlook
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OCN 0.5 Mo lead NDJ T Outlook
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CMP 0.5 Mo lead NDJ T Outlook
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OFFICIAL NDJ 2001-02 T Outlook
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CMP P Forecasts
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CMP NDJ 2000-01 P Verification
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CCA 0.5 Mo lead NDJ P Outlook
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OCN 0.5 Mo lead NDJ P Outlook
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Official NDJ 2001-02 P Outlook
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Operations Concept for Ocean/Atmosphere Model

• NCEP currently uses dynamical coupled
  ocean-atmosphere models in combination with
  statistical models to produce seasonal outlooks
  with ½ to 5 ½ month leads and, to a lesser
  extent, monthly outlooks with ½ month lead.
  Enhanced model operations which include increased
  numbers of ensemble members, more frequent model
  runs and enhanced capability to include the
  influence of within-season variations in SST and
  OLR will be used to
• - Produce more highly resolved distributions of
  predicted
• variables,
• - Produce forecasts which increasingly and more
  appropriately
• reflect the influence of intra-seasonal
  variability on middle
• latitude climate,
• - Produce improved week 2 and monthly outlooks
  and develop
• and implement new outlook products for
  the week 3-4 period.
• - Develop and implement new products to predict
  seasonal
• variations in frequency of extreme events,
  primarily during
• ENSO.

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Detailed operations concept for ocean-atmosphere
model

• Currently, coupled dynamical model forecasts are
  one of several tools used in
• preparing long-range outlooks. NCEPs model is
  run to produce one set of
• ensemble forecasts per month during the first
  week of the month. This is done in a
• two-tiered system, in which first, an ensemble of
  16 ocean forecasts are created
• using a coupled GCM. The average of these is
  used as the official SST forecast.
• This SST forecast is then used as the lower
  boundary for an AGCM to create a set
• of 20 atmosphere ensemble members. The forecasts
  are run out to 9 months. A
• 20-year run of the AGCM is created each month.
  The seasonal means from this
• run are used as the climatology to create anomaly
  maps from each of the
• ensemble members. The means of these anomaly
  maps are used as the forecast
• tools which are presented to the forecasters.
• The forecasters use the NCEP model tools,
  together with other model tools to
• subjectively create outlook maps of the
  probability of monthly and seasonal mean
• temperature and total precipitation category.

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El Nino Global Impacts
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Summary

• CPC long-lead seasonal outlooks are produced
  using, in order of perceived reliability
• - ENSO composites, trend, soil moisture and
  dynamical models (DMs) and statistical models.
• Frequent model changes hamper perceived
  reliability of DMs.
• Lack of convincing information about model biases
  reduces perceived reliability of DM forecasts.
• Weather/climate impacts of AO, MJO, PDO are
  known.
• Prediction of AO, MJO, PDO is not yet possible.
• DMs cannot yet predict subtle differences among
  ENSOs.
• Stratospheric annular mode (SAM) is a link to AO
  prediction.
• DMs ability to predict SAM is unknown/doubtful.
• Relationship of Indian Ocean to predictable
  signals is unclear.
• Relationship of QBO, Southern Hemisphere
  mid-latitude circulations to predictable signals
  is unclear.