The image below shows the average wettest periods of rainfall that fall during tropical cyclones and their
remnants, and the percentage they make up of the storm total. The y-axis of the graphic shows the percentage
of the storm total which falls within the x-axis period of time, determined in hours. The two rows of data
beneath the graphic show the average wettest amounts per the time frame on the x-axis and the maximum
amounts that have fallen within the time frame listed on the x-axis. Data from the Hourly Precipitation
Publications from the National Climatic Data Center were used for this graphic, which includes first-order
observation sites and cooperative rainfall sites with Fisher-Porter rain guages.
For example, the wettest 30 minutes (0.5 hours) of rainfall during a tropical cyclone passage averages 10% of
the storm total, which is 1.40" of precipitation. The maximum amount that has fallen within 30 minutes
during a tropical cyclone within the 1991-2005 time frame is 3.04".
