The Method for Object-based Diagnostic Evaluation (MODE) applied to numerical forecasts from the 2005 NSSL/SPC Spring Program

The authors use a procedure called the method for object-based diagnostic evaluation, commonly referred to as MODE, to compare forecasts made from two models representing separate cores of the Weather Research and Forecasting (WRF) model during the 2005 National Severe Storms Laboratory and Storm Prediction Center Spring Program. Both models, the Advanced Research WRF (ARW) and the Nonhydrostatic Mesoscale Model (NMM), were run without a traditional cumulus parameterization scheme on horizontal grid lengths of 4 km (ARW) and 4.5 km (NMM).

MODE was used to evaluate 1-h rainfall accumulation from 24-h forecasts valid at 0000 UTC on 32 days between 24 April and 4 June 2005. The primary variable used for evaluation was a ?total interest? derived from a fuzzy-logic algorithm that compared several attributes of forecast and observed rain features such as separation distance and spatial orientation. The maximum value of the total interest obtained by comparing an object in one field with all objects in the comparison field was retained as the quality of matching for that object.