A WEIGHTED CONSENSUS APPROACH TO TROPICAL CYCLONE 96-H AND 120-H TRACK FORECASTING

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A WEIGHTED CONSENSUS APPROACH TO TROPICAL CYCLONE
96-H AND 120-H TRACK FORECASTING
1Lt James Hughes (Mar 2007)Advisor Prof.
Russell Elsberry 2nd Reader Mark
BootheBeneficiary JTWC and DoD

• A long-range (96 h 120 h) weighted position
  consensus for tropical cyclone tracks is
  evaluated for 24 western North Pacific storms in
  2006.
• The first weighted position technique simply
  weights the 96-h, 108-h, and 120-h dynamical
  model positions inversely to their distances from
  the 60-h, 66-h, and 72-h consensus positions,
  which yields modest improvements over an
  unweighted position consensus
• The second weighted consensus technique uses the
  same weighting factors but is applied to the
  forecast motion vectors to assess 96 h 120 h
  track errors, which yields reductions in track
  errors of 9.9 at 96 h and 5.6 at 120 h
  relative to unweighted postion consensus errors.

• The 96 h 120 h weighted position consensus
  (grey stars) indicates an improvement over an
  unweighted consensus (blue asterisks).
• Improvement is due to assigning the NOGAPS model
  (NGPI) the largest weighting factor (0.75), since
  the NOGAPS model is closest to the consensus from
  60 72 h.