• Consider the two main uses are flight planning and traffic flow management.

• Consider how the forecast will be developed and presented (i.e., purely probabilistic or deterministic).

4. How will we know when we are done? What verification scheme makes the most sense from an aviation perspective?

Many workshop participants thought that the 5- to 10-year goals for forecast accuracy set by the FAA in preparation for this workshop (desired FAR ≤0.20, desired POD ≥0.80, maximal FAR of 0.30, minimal POD of 0.60) were unrealistic and, in fact, ill posed. That is, improvement in skill as measured by metrics such as POD and FAR does not necessarily translate into increased value for the end user owing to numerous mitigating influences (e.g., constraints on the overall air traffic system, nonweather impacts, and industry-government politics). Further, such metrics, which are perfectly suited for large-scale weather features, do not apply to spatially irregular and highly intermittent convective phenomena. Because of these concerns, the workshop presenters did not focus specifically on these goals but rather on improving forecasts more generally.

This chapter summarizes the information presented during this session of the workshop. Text boxes for each discussion topic call out key points identified by individual presenters. These key points do not reflect the consensus of the presenters or the committee.

Accurate prediction of convection in the 2- to 6-hour time range may not be amenable to an “engineered” solution without further research related to improved understanding of convection and the practical limits to its predictability. During the workshop, Richard Carbone of the National Center for Atmospheric Research (NCAR), J.Michael Fritsch of Pennsylvania State University, and Cynthia Mueller of NCAR presented their visions of a 2- to 6-hour forecast strategy. These respective visions follow sequentially below.