Near-surface forecast challenges at the Air Force Weather Agency

Turbulence forecasting is a significant concern for the United States Air Force Weather Agency. Turbulence is responsible for dangerous flight conditions which can result in injuries and damage to aircraft. Creating products that can successfully forecast conditions favorable for turbulence is a high priority of the Aviation Hazards team within the 16th Weather Squadron (16WS). Atmospheric turbulence, specifically in the lowest portions of the troposphere, is a particular forecast problem due to the different physical processes that can be responsible for the creation of conditions hazardous for aviation operations. The goal of this work, which will be the focus of this presentation, is to present work detailing recent efforts to add to the current suite of products used in near surface turbulence forecasting.

One particular challenge in the process of turbulence forecasting is using numerical models to represent different atmospheric processes responsible for near-surface turbulence, such as strong low level winds, convective air parcels, and trapped lee waves. It is also preferable to expedite information to forecasters as quickly and efficiently as possible without providing too much information. In particular, the complexities of trapped lee wave forecasting have been addressed through tutorials available to forecasters online, but these tutorials can be time consuming, do not take into consideration every region where conditions favor trapped lee waves, and do not always take into account the geographical extent of turbulence potential caused by the propagating wave. Charts which comprehensively display the potential for the development and propagation of trapped lee waves have been developed to ease the forecast process.

In addition to addressing the challenges posed by the physical processes of turbulence, recent emphasis has been placed upon probabilistic and ensemble forecasting methods. Considerable progress has been made within the 16WS to develop a variety of atmospheric products using probabilistic output from ensemble forecasts. Adding a near-surface turbulence product to the suite of ensemble products has been a high priority. The developmental process of probabilistic near-surface turbulence algorithms, as well as verification methodology and statistics, will be presented.