The Navy's Analog Scheme for Forecasting Tropical Cyclone Motion over the Northeastern Pacific Ocean

The Navy's EPANALOG (Northeastern Pacific Analog Tropical Cyclone Tracker) forecast program is introduced. EPANALOG selects analog tropical cyclones from a 25-year Northeastern Pacific Ocean history. The selected analog tracks, statistically adjusted for position, vector motion, and date differences between them and the recent history of the tropical cyclone being forecasted, and composited into a single forecast track. Verification of EPANALOG forecasts to 96 hours are shown for randomly selected historical tropical cyclones as initiated from best-track positions statistically adjusted to simulate position inaccuracies, as well as for forecasts general from 1973 operational tropical cyclone positions. The latter are intercompared with a homogeneous set of objective persistence an MOHATT forecasts as well as subjective official forecasts for the 24-, 48- and 72-hour intervals. The accuracy of the 1973 EPANALOG is shown to generally exceed that of the existent techniques for all forecast intervals tested.