Evaluation and applications of NCEP Stage II and Stage IV gage-corrected radar precipitation estimates over the Carolinas

The National Centers for Environmental Prediction have created national mosaics of radar precipitation estimates calibrated with surface gage observations. These gridded products provide hourly and 6-hourly precipitation estimates on ~4km grid using Multi-sensor Precipitation Estimates (MPE) algorithms used by the NWS River Forecast Centers. Such high-resolution gridded precipitation estimates could be valuable for many hydrological applications, such as drought monitoring, irrigation scheduling, and mesoscale precipitation research.

NCEP Stage II estimates combine radar precipitation estimates with surface gage values, accounting for general bias in the radar returns. Stage II estimates are quickly available and effective for precipitation monitoring. Stage IV (MPE) precipitation estimates, with an added human quality control aspect, are generally more accurate and therefore valuable in monitoring and research applications. However, Stage IV products are not as rapidly available for dissemination.

The NCEP Stage II and Stage IV (MPE) precipitation estimates are evaluated over the Carolinas for accuracy at several time scales. Independent surface precipitation observations, including NC ECONet automated gages and NWS Cooperative observer stations, are used to verify the NCEP estimates. Comparative statistics and confidence intervals are calculated for the region based on errors at various time scales. Two applications of the gage-corrected radar estimate products are discussed and evaluated: (1) development of a heavy precipitation mapping and alert system for storm water quality management, and (2) mesoscale precipitation climatology research.