A second evaluation of aviation-impact variables generated by maps

This paper describes the second evaluation of aviation-impact variables derived from the MAPS model analyses and forecasts. This is part of an ongoing program at the Forecast Systems Laboratory (FSL), sponsored by the Federal Aviation Administration’s (FAA) Aviation Weather Development Program. The evaluation was conducted using an independent verification dataset obtained from the Storm-scale Operational and Research Meteorology Fronts Experiment Systems Test (STORM-FEST), from 1 February through 15 March 1992. MAPS produced analyses and forecasts at specific station locations for verification, for upper air, surface, and profiler stations, as well as at pilot report (PIREP) locations. In general, analyses and forecasts of winds and temperatures aloft reported the expected rawinsonde errors, with some exceptions. It was found through examination of the statistical measures that MAPS also tends to misplace the low-level jet, resulting in the appearance of less skill, which is only due to a small number of cases. MAPS does not resolve multiple freezing levels. The E2 version of MAPS indicated a dry bias aloft, which in turn affected the skill in diagnosing of cloud amounts and ceilings. Surface variable analyses and forecasts were generally good, with most variables beating persistence. Exercise 2 was the first time turbulence and icing was diagnosed. MAPS did the best when compared to PIREPS directly, when using the Richardson number algorithm for turbulence and the Schultz-Politovich algorithm for icing.