CPC Drought Forecasting and NIDIS

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CPC Drought Forecasting and NIDIS

• Douglas Le Comte
• NOAA/CPC
• 5th U.S. Drought Monitor Forum
• Portland, Oregon
• October 10-11, 2007

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Outline

• Overview of how the CPC Outlook is put together
• Recent changes to the Drought Outlook
• Verification How are we doing?
• The Future Meeting the Needs of NIDIS

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Latest Seasonal Drought Outlook
http//www.cpc.ncep.noaa.gov/products/expert_asses
sment/seasonal_drought.html
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Short and Long-term Forecast Contributions


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Principal Drought Outlook Inputs
2-Wk Soil Moisture
CPC Long-Lead Precip. Outlook
Constructed Analogue Soil Model
Palmer 4-mo Probabilities
Medium-Range Fcst
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Recent Changes

• Began twice/month schedule (1st and 3rd Thursday)
• Expanding CPC authors
• Changed wording of headings (Tendency, valid
  dates)

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Changes Recently Considered

• Add separate category for drought intensification
  
• Abolish or re-define Some Improvement category
• Automate verification calculations

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Drought Verification Jul-Sep 2007
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Improvement over PersistencePercent of Grid
Points Correct vs a Forecast Based on Persisting
Droughts
Long-term mean 13
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NIDIS and Drought ForecastingFrom the NIDIS
Implementation Plan, June 2007

• Ensemble drought prediction is needed to
  maximize forecast skill, and downscaling is
  needed to bring coarse resolution drought
  forecasts from General Circulation Models down to
  the resolution of a watershed.
• Improved understanding of the dynamical causes
  of long-term trends.
• Two basic approaches to drought prediction 1)
  prediction of drought indices, and 2) prediction
  of hydrological conditions.

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FY08 Climate Test Bed Priority for NIDIS-Drought

• New Drought Monitoring Products Multi-model
  ensemble NLDAS
• New Drought Forecast Tools
• Objective drought forecasts based on CFS and
  statistical tools
• Improved seasonal forecasts based on improved
  land-atmosphere coupling
• Improved medium-range prediction
• based on NAEFs

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Princeton Soil Moisture Forecast
Ensemble Streamflow Prediction
Coupled Forecast System
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University of Washington Forecasts
http//www.hydro.washington.edu/forecast/monitor/o
utlook/index.shtml
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Two Path Approach to Improving Drought Forecasts
at CPC

• Continue to produce and refine seasonal drought
  outlooks for the general public
• Develop objective seasonal probability forecasts
  for drought (guidance useful for an array of
  users)

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One Prototype Suggestion of a Probabilistic
Forecast
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Prediction is very difficult, especially
about the future Niels Bohr, Danish physicist
(not Yogi Berra)