The leading cause of fatal weather-related aviation accidents in the U.S. is VFR (visual flight rules) flight into regions of low ceiling and/or visibility where IFR (instrument flight rules) prevail. The poor safety record of these operations imposes a high priority on improved methods to outline current and forecast ceiling and visibility conditions for pilot use.

Recent development of an automated ceiling and visibility analysis system for the continental U.S. utilizes satellite, surface observations and terrain information to formulate real-time ceiling and visibility analyses, a cloud mask and user confidence fields, all updated every 5 minutes. The system is undergoing certification for operational use in 2007. A second system focused on automated 1-10 hr forecasting of ceiling and visibility utilizes agile selection among numerical models, MOS forecasts and observations-based ruleset forecasts to synthesize forecasts of improved skill.

This paper outlines the structure and performance of the mature analysis system and early progress toward development of the agile forecast system. This work is carried out by the National Ceiling and Visibility product development team under funding from the FAA's Aviation Weather Research Program.