Probable Maximum Precipitation is called PMP in short form.
Probable maximum precipitation is used in the design of large hydraulic structures, such as drainage ditches in large dams.
There appears to be a physical upper limit on the amount of precipitation that can fall on a given area at any given time.
Probable maximum precipitation is the largest or most extreme amount of precipitation physically possible over a given period of time on a rainfall gauge or body of water. It is the rainfall over the pool that causes flooding without the risk of excess.
Probable maximum precipitation can be calculated as given below.
are the annual series mean of maximum precipitation, the frequency coefficient (depending on the statistical distribution of the series, the year of record, and the return period), and the standard deviation of the series. K~ 15