The Flash Flood Monitoring and Prediction (FFMP) software was implemented in most National Weather Service (NWS) offices in 2002. FFMP computes Average Basin Rainfall (ABR) in watersheds down to 5 km2 in area. ABR is compared to Flash Flood Guidance (FFG) to determine the potential risk of flash flooding in each stream in the FFMP stream database. One person from each NWS office will attend a "basin customization" course at COMET to learn how to modify the FFMP stream database.

The purpose of "basin customization" is to improve the flash flood detection capability of FFMP, and increase flash flood warning lead-time. The increase in detection capability, or lead-time, can be accomplished in two different ways. The existing FFMP watersheds can be divided into smaller segments, showing more detail in the spatial distribution of heavy rainfall. In addition, the modification of basin specific FFG based on steep terrain, the percentage of impermeable soil, or multiple rainfall events can improve flash flood detection.

This paper will summarize the subject matter covered during the basin customization course and describe how the application of the "basin customization" training can improve FFMP performance at the local forecast office