These graphics show probabilities of sustained (1-minute average) surface wind speeds equal to or exceeding 34 kt...39 mph (tropical storm force). These wind speed probability graphics are based on the official National Hurricane Center (NHC) track, intensity, and wind radii forecasts, and on NHC forecast error statistics for those forecast variables during recent years.
Each graphic provides cumulative probabilities that wind speeds of at least 74 mph will occur during cumulative time periods at each specific point on the map. The cumulative periods begin at the start of the forecast period and extend through the entire 5-day forecast period at cumulative 12-hour intervals (i.e., 0-12 h, 0-24 h, 0-36 h, ... , 0-120 h). An individual graphic is produced for each cumulative interval, and the capability to zoom and animate through the periods is provided. To assess the overall risk of experiencing winds of at least 74 mph at any location, the 120-h graphics are recommended.
These probabilities will be updated by the NHC with each advisory package for all active tropical cyclones in the Atlantic and eastern North Pacific basins. While separate graphics are focused on each individual tropical cyclone, probabilities resulting from more than one active tropical cyclone may be seen on each graphic.