How accurate are cyclone warnings from the Bureau of Meteorology?
Tropical cyclones have historically had a reputation for being unpredictable. Much effort has been dedicated to improving the forecasting skill in both location and intensity. The Bureau of Meteorology routinely issues forecasts of cyclone location and intensity at 12, 24 and 48 hour time-steps. All official forecasts are verified by comparison with the best track, the official estimate of the location and intensity of a tropical cyclone. A best track is prepared for every tropical cyclone, after the fact, using all available data. Cyclones vary considerably in their predictability. Some exhibit rapid changes in intensity or change course, speed up or slow down, primarily in response to changes in the surrounding environment. Cyclone Lena (1993), for example, was moving to the west but made a U-turn and returned close to its original path. The 24-hour forecast error for Lena was 258 km, more than double the 1999/2000 – 2003/04 average. Cyclone Gwenda (1999) intensified from a category
