65th IHC Booklet/Program (pdf - 4.9MB) - Office of the Federal ...

Prediction of Consensus TC Track Forecast Error (2005-2010)
James S. Goerss
(jim.goerss@nrlmry.navy.mil)
Marine Meteorology Division, Naval Research Laboratory
Funded by a JHT project, a graphical predicted consensus error product (GPCE; Goerss 2007)
was first developed and installed on the ATCF at both NHC and JTWC in 2004. Using GPCE’s
pool of predictors, revised regression models to be used for the upcoming season were derived
and installed on the ATCF at both centers from 2005 to 2010. These regression models are used
to determine the radii of circular areas drawn around the consensus model forecast positions
within which the verifying TC position is expected to be contained approximately 70% of the
time. These circular areas are then graphically displayed on the ATCF for use by the forecasters
at NHC and JTWC. For each season from 2005 to 2010, GPCE is validated for the Atlantic and
Eastern North Pacific basins. For each forecast length, the GPCE validation percentage is
compared with the consensus forecast error for the season. As one would expect, since the
GPCE regression models are derived using the results from previous seasons (e.g., for 2010 the
dependent data for the Atlantic basin came from the 2003-2009 seasons), the GPCE validation
percentages for a given season are larger/smaller than the 70% target when the consensus
forecast errors for that season are smaller/larger than average. For the entire period from 2005 to
2010, the GPCE validation percentages for the Atlantic basin were 75%, 76%, 76%, 79%, and
79% for 24h, 48h, 72h, 96h, and 120h, respectively. The respective errors for the eastern North
Pacific basin were 71%, 73%, 79%, 80%, and 82%. All of the GPCE validation percentages are
larger than the target for the entire period. This result is consistent with the general reduction in
consensus forecast error from 2005 to 2010 due to improvements in individual track forecast
models and the addition of more “good” models (e.g., ECMWF and HWRF) to the consensus.
Session 6 – Page 1