A Preliminary Look at Using Rainfall Average Recurrence Interval to Characterize Flash Flood Events for Real-time Warning Forecasting.

Autor: LINCOLN, W. SCOTT, THOMASON, RACHELLE F. L.
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Zdroj: Journal of Operational Meteorology; 5/10/2018, Vol. 6 Issue 2, p13-22, 10p
Abstrakt: Characterization of flash flood severity in real-time has been highlighted by National Weather Service (NWS) service assessments for almost two decades. Current flash flood warning techniques provide limited guidance on determining potential severity of flood impacts. Recent software updates allowing for the estimation of rainfall average recurrence intervals (ARIs) in real-time help improve the nowcasting of flash flood events, but guidance is lacking on specific ARI values to use as thresholds. Researchers at the NWS Lower Mississippi River Forecast Center collected data for 24 flash flood events across the eastern United States. Reports of flash flooding were characterized based upon relative severity, and then matched to rainfall ARI values. Preliminary results from this study suggest that utilizing the 2-yr ARI contour derived from 3-h rainfall would capture approximately 90% of flash flood reports. It was also found that more significant flash flood impacts generally became more common with an increased 3-h rainfall ARI, with major flooding of roadways or structures (at least 0.91-m, or 3-ft, of inundation) becoming likely by around a 25-yr max ARI value for the storm. Due to biases in the available cases used in the analysis, results are considered preliminary and subject to considerable case-by-case variability. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index