NetSTORM can read US NCDC meteorologic data in several formats, including the TD-32000 and TD-3240 formats that have been used for many years for storing and transmitting daily and hourly precipitation data. The program reads data formatted in a simple year – month – day - hour – minute tabular format, and can import or export to standard Windows date-time format (e.g. month/day/year hour:minute). Certain modules of the program can process data for multiple rain gages, so that it is possible to compute an IDF analysis for all gages for an entire state at once.
When NetSTORM imports NCDC TD-3240 hourly data, it performs a stochastic disaggregation of aggregated precipitation totals that have the appropriate data flag in the input data. The disaggregation algorithm produces a random distribution over the duration of the accumulated observation period, but this can be a considerable improvement over the smoothed or lumped distribution that would be obtained by reading the data using SWMM4 or HydroData software.