Tropical Cyclone Rainfall Duration and Maxima

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".

Rainfall Accumulations Per Time Period (1991-2005)