Wind speed forecast and probability chart

It shows the National Hurricane Center (NHC) maximum 1-minute wind speed forecast as a broad blue line on a chart of wind speed versus forecast period. The narrower lines, labeled 10% and 20% (or 30%), indicate the probability that the maximum wind speed will be some other magnitude than what the NHC has forecast. For example, the cyclone could become stronger than the NHC has forecast, with there being a 10% chance that the wind speed will attain the level indicated by the 10% line plotted above the NHC forecast. The probabilities are based on NHC forecasts from 1988-1997. The data base excludes unnamed tropical depressions. Current advisory information is shown near the bottom of the chart. When applicable, the Saffir/Simpson Hurricane Scale is shown at right. "Inland" is indicated for periods when the cyclone center is forecast to be over land. "Ext" indicates that the NHC forecasts the cyclone to be extratropical at that time.