An Operational Perspective For Evaluating Convective Nowcasts For Aviation

Abstract

As the United States is moving toward automated air traffic decision tools (NextGen), evaluating forecasts for potential operational use is key. Air traffic management, current or future, needs convective nowcasts (0-6 h) for information on how to best route traffic between aviation centers, sectors, and jetways. Current and future operational air traffic management needs focus on how to best supplement (or replace) the current operation standard, the coarse Collaborative Convective Forecast Product (CCFP). Finer scale products (i.e. simulated radar reflectivity from models) have to be evaluated for additional information, namely value added by increasing structural information and increasing temporal resolution. Structure can be quantified by examining bias behavior of this fine scale forecast or by providing information on the convective objects or clusters of objects within, and outside of, the broad-scale operational standard forecast. Additional structural information comes from evaluating the porosity of sectors when overlaid with convective objects for the assessment of potential reductions in air traffic capacity. Value added by increasing the temporal resolution of forecasts can be evaluated by a planning point evaluation of all forecasts covering a valid range of time. In this evaluation, all lead times from a forecast are assessed from forecast initial time until a point beyond the valid time of the final lead using all observations present in that valid range. A common thread to all of these evaluations is being able to stratify all days from a study period into different degrees of air traffic impact which is made possible from a normalized air traffic impact score. Other important stratifications involve the delineation of significant and non-significant convection. This note will give some detail to the approaches outlined above