Comparison of short-period daytime convective rainfall accumulations with total column precipitable water: Derivation of an operational forecasting technique

Abstract

A major forecasting challenge is predicting the likely intensity of rainfall in convective situations in which intense short-period rainfall can lead to surface water flooding. The study demonstrates a useful correlation between precipitable water and 1 hr gauge-derived rainfall accumulations in situations with deep instability and relatively slack flow in depth. The correlation forms the basis of a forecasting technique, independent of numerical weather prediction (NWP) model forecasts of rainfall, being applied at the UK's Met Office Flood Forecasting Centre (FFC).