The WRF-NMM nested grid system was applied in real-time for the 2006 Torino Italy Olympics to provide high resolution forecasts to drive dispersion models. Examples and evaluation of NMM performance for this application will be described. The NCEP Forecast Verification System (FVS) is regularly used to evaluate most NCEP model performance. New results using FVS to evaluate predictions that are critical to dispersion model applications (eg: planetary boundary layer height, cloud cover, low level winds) will also be summarized.
More detailed evaluation of the WRF-NMM turbulence predictions are also being evaluated with the DTRA team. Special surface flux and atmospheric boundary layer turbulence measurements were deployed at several locations during the 2002 International H20 Project (IHOP). Retrospective simulations using the WRF-NMM for several cases during IHOP were evaluated using these special turbulence measurements. The flux and turbulence evaluations are important to help assess whether meteorological and dispersion models can be coupled more tightly by driving the dispersion predictions with these more basic turbulence fields.
In addition, special ensemble based prediction systems on global (The Medium Range Ensemble Forecast System with horizontal resolutions of around 100 km) to regional scales (The Short Range Ensemble Forecast System with horizontal resolutions of around 32 km) can also be utilized for dispersion applications. The DTRA team supported by NCEP is testing these ensemble predictions to derive velocity variance and cross correlation predictions which in turn are used to estimate large scale uncertainty information in HPAC. Probabilistic products available from these systems and their application to dispersion will be presented. NCEP plans to expand upon these results and experience during upcoming field tests, and to further improve and expand the capability to provide accurate high-resolution and probabilistic weather forecast information to hazard and consequence assessment operations.