The Storm Prediction Center (SPC) is collaborating with the National Severe Storms Laboratory (NSSL) and the Mitre Corp. Center for Advanced Aviation System Development to explore the ability of post-processed mesoscale and storm-scale ensemble prediction systems to provide probabilistic guidance that aids forecast confidence and decision support of aviation-related convective hazards. The National Centers for Environmental Prediction (NCEP) Short Range Ensemble Forecast (SREF) is routinely post-processed by the SPC to produce probabilistic convective guidance on phenomena such as thunderstorms, severe thunderstorms, and thunderstorm cloud tops. These post-processed SREF forecasts are based entirely on the predicted mesoscale environment and have been shown to provide useful guidance to convective forecasters, but they do not explicitly predict details of the convective coverage, mode (e.g., isolated storms or mesoscale convective systems) or storm-scale evolution. To address these needs, the SPC and NSSL are working with the University of Oklahoma Center for Analysis and Prediction of Storms (CAPS) to develop and evaluate a state-of-the-art experimental Storm Scale Ensemble Forecast (SSEF) system. The SSEF is available to the SPC experimentally each spring from early April through early June as part of the NOAA Hazardous Weather Testbed annual Spring Experiment. Although still early in its research and development stage, the SSEF has shown the potential to provide useful probabilistic information on convective mode and evolution, including the ability to predict correctly the occurrence of convective lines versus discrete cells up to a day in advance.

This paper will demonstrate how the probabilistic ensemble guidance could be used to help support the air traffic management system. Beginning with the operational SREF, forecasters and decision makers can extract reliable probabilistic guidance of large-scale features such as general areas where thunderstorms are more likely to form and an overall indication of their intensity within time frames that better correspond to current operational planning practices (less than 30 hrs). The experimental SSEF can then be used to identify details of convective mode and coverage, resulting in a more precise probabilistic forecast of potential impacts to the air traffic management system. Cases studies from the spring of 2008 will be shown that illustrate the use of SREF and SSEF probabilistic guidance to identify aviation convective hazards, and their potential interpretation and application to the air traffic management system.