Skip to content

Tracking the raindrop from the sky to the summit to the sea...

CI-FLOW: Rainfall

Tarboro River inundation map

Hurricane Irene, as observed by the Q2 system. [+]

“Accumulated rainfall” is an estimated amount based on radar-measured rainfall intensity and rain gauge observations. Unfortunately, these tools cannot accurately show how much rain actually fell and how the rainfall amounts were distributed. Radar has excellent resolution, but radar cannot scan at the surface of the earth. Also, radar coverage is inconsistent from place-to-place and storm-to-storm. Rain gauges can be more accurate than radar, but they are usually spread too far apart to accurately show how rainfall is distributed.

Measuring rainfall

CI-FLOW uses data from NSSL’s National Mosaic and Multi-sensor Quantitative Precipitation Estimation system, most commonly referred to as NMQ/Q2, to estimate the amount of rainfall that has fallen over the Tar-Pamlico and Neuse River basins.  NMQ/Q2 combines data from radars and rain gauges to generate rainfall estimates over an area. This multi-sensor technique combines the most desirable aspects of rainfall estimation into one product. The NMQ/Q2 rainfall estimates are fed into a model that predicts which streams and rivers will flood.

Predicting Rainfall

CI-FLOW uses data from the NWS’s Weather Prediction Center Offsite link warning (WPC) to forecast the amount of precipitation that will fall over the Tar-Pamlico and Neuse River basins.