Ensemble Prediction of Oceanic Convective Hazards
Randall Bass, Federal Aviation Administration, Washington, DC
Ken Stone, National Center for Atmospheric Research
James Pinto, National Center for Atmospheric Research
Matthias Steiner, National Center for Atmospheric Research
Cathy Kessinger, National Center for Atmospheric Research

Abstract
An important aspect in strategic (~24 hours and longer) planning for transoceanic flights is the acquisition and interpretation of forecasts of weather hazards such as convection that might be encountered along a desired flight path.  While current officially sanctioned significant weather forecasts (SIGWX) are manually generated and deterministic (i.e., depict a single possible realization), future products are planned to be gridded probabilistic forecasts, derived from a combination of numerical weather center outputs (e.g., World Area Forecast Center (WAFC) London and WAFC Washington). 

The Federal Aviation Administration is sponsoring a project called the Ensemble Prediction of Oceanic Convective Hazards (EPOCH) to produce global probabilistic convective hazard guidance forecasts with lead times of up to 36 hours as needed for strategic planning of transoceanic flights. This project develops techniques for optimally combining forecast information from multiple NWP model ensembles into a single calibrated forecast depicting the chance of aviation-impacting convection to occur at a given location and time. The methods developed for EPOCH will lead to an improved forecast and depiction of aviation-impacting convection around the globe that will provide users with better weather data for route planning, fuel loading, and impact mitigation and avoidance. Integral components of the project include development of a verification field (used for calibration and assessment of convective weather forecasts) and application and extension of diagnostic assessment tools to aid in developing and improving the ensemble post-processing algorithms.  The end result is a global ensemble convective weather forecast method to be delivered to the Washington and London WAFC for integration and use operationally. As such, these methodologies provide a viable basis for the envisioned future global harmonization of WAFC-generated probabilistic aviation weather hazard guidance products. This presentation will describe and demonstrate the EPOCH project, its purpose and benefits to air traffic operations.