Impacts on RUC short-term ceiling and visibility forecasts from high-resolution data

Skillful short-term (1-6 h) forecasts of ceiling and visibility are critical to aviation safety and efficiency, but are difficult to achieve due to the spatial and temporal variability of clouds and fog.

We report on our efforts to assimilate high temporal and spatial resolution data (GPS-integrated precipitable water, METAR, mesonet, TAMDAR) into the RUC, and to specifically consider the impact of these data on ceiling and visibility forecasts through various assimilation methods.

In addition to discussing multi-month trends in ceiling and visibility forecast skill, we will also report on results from a series of observation sensitivity experiments in which various data sources were withheld from the RUC, and in which different assimilation schemes are tried, while the RUC was run repeatedly over a 10-day period comprising a variety of weather conditions.

To facilitate this work we have built, and will report on, a new verification system that compares RUC ceiling and visibility reports with METAR reports every hour, substantially increasing the number of samples--and statistical reliability--over our older verification system.