How are the Wind Probabilities generated?
Centered on the latest JTWC forecast, 1000 plausible alternate forecasts are created, each with a different evolution of track, intensity, and size. The track and intensity variations are determined by random sampling of historical track and intensity errors over the past 5 years. Size variations are determined by a climatology and persistence (CLIPR) model and its error components. For each alternate forecast, swaths of particular wind speeds (34-, 50-, 64KT) are calculated and saved. Finally, probabilities are calculated on a degree latitude/longitude grid by counting the fraction of alternate forecasts in which each grid point falls within a swath of each wind speed. Back to top Q: What numerical models does JTWC use? A: The current consensus forecast track used at JTWC, called CONW, is composed of seven baroclinic dynamical models and one barotropic model. The dynamical model tracks included (labeled with their first interpolation) are: NGPI, GFNI, AVNI, TCLI, JGSI, EGRI, and ECMI.
