Statistical Methods in the NWS National Blend of Global Models Part 2

Statistical Methods in the NWS National Blend of Global Models Part 2
  • Describe the role and limitations of URMA for the NBM
  • Describe the methodologies used in the NBM Versions 2 and/or 3 to calculate:
    • Probability of Precipitation and Quantitative Precipitation
      • Smoothing raw and quantile-mapped model guidance
    • Precipitation Potential Index
      • Dependent on maximum floating PoP12
    • Maximum/Minimum Relative Humidity
      • Determine highest and lowest relative humidity value
    • Cloud Ceilings and Surface Visibility
      • Instrument Flight Rules
      • Critical Success Index
    • Ocean Wind
      • Speed: Bias-correction and cumulative distribution functions
      • Direction: Calculating cluster means
  • Describe how model biases are addressed in the Blend using:
    • Decaying average
    • Quantile mapping