The Seventh Annual Flash Flood and Intense Rainfall Experiment. Part II: An Objective Overview of the Experimental Models and Ensembles Used in FFaIR 2019

The 7th Annual Flash Flood and Intense Rainfall (FFaIR) Experiment was held at the Weather Prediction Center (WPC) Hydrometeorology Testbed (HMT) in College Park, MD over four weeks during the period from June 17 to July 19, 2019. The FFaIR Experiment brings together participants from across the weather enterprise to simulate a pseudo-operational environment in an effort to create experimental probabilistic forecasts and evaluate emerging models, tools, and datasets with the ultimate goal of improving flash flood forecasting. During the experiment, participants utilized the latest experimental deterministic convection allowing models (CAMs), most utilizing the Finite-Volume Cubed-Sphere Dynamical Core (FV3). A variety of convection allowing ensemble systems were also analyzed. Subjective and objective data were collected from evaluations and analysis of the experimental guidance and forecasts. A major theme for the 2019 FFaIR Experiment was to analyze the new FV3-based CAM deterministic models as well as the ensembles to produce probabilistic short range (6-24 hour) excessive rainfall forecasts.

The 2019 FFaIR Experiment evaluated the skill of high resolution deterministic CAMs and convection allowing ensemble systems for short-term excessive rainfall forecasts. Experimental “first guess” forecasts were evaluated in the Day 1 range as a possible starting point for the WPC operational excessive rainfall outlook (ERO). The 2019 experimental forecasts were verified using WPC’s experimental verification system, the Unified Flood Verification System, for the third year in a row. This presentation will discuss the objective verification of the 2019 experimental deterministic models and ensembles. Objective verification methods included using the Model Evaluation Tools (MET), specifically the Method for Object-Based Diagnostic Evaluation (MODE) analysis tool. Objective analysis of the experimental forecasts issued during FFaIR will also be highlighted.