Adverse weather and air traffic delays

Most commercial flights (80%) reliably deliver passengers and cargo on time within a small fraction of the en route time. Of the remaining 20%, it is widely recognized that about 70% of the delays, diversions and cancellations (DDCs) are related, somehow, to adverse weather. If so, skillful weather forecasts and judicious traffic management should hold a promise for reducing DDCs. A prerequisite is to define and empirical baseline for the qualities of adverse weather that strongly affects the DDCs. The essential difficulty is that weather elements (ceiling, visibility, surface winds, turbulence, and thunderstorms) are defined locally, while the DDCs are a parameter of the National Airspace System (NAS). Three approaches are taken: analysis of terminal weather, analysis of routes, and empirical modeling. The geographical, seasonal, and diurnal variability is reduced by selective stratification of the data. The results of these analyses are a baseline of adverse weather that is dependent on the region, month and temporal quadrant of the day. The sensitivity of the DDCs to the baseline of adverse weather will be investigated.