Improvements in the summer 2011 version of blending used in CoSPA

CoSPA is a forecast system that has been developed under FAA AWRP funding and recently fielded in the summer 2010 under FAA Reduce Weather Impact (RWI) program funding. CoSPA provides a rapidly-updating depiction of past, current and future weather for aviation planning. Forecasts of vertically-integrated liquid water (VIL) and echo tops, which serve as proxies for aviation weather hazards related to convective weather, are produced by blending extrapolation nowcasts produced by MIT-LL (based on the Corridor Integrated Weather System (CIWS) technology) and high-resolution numerical weather prediction model forecasts produced by NOAA/GSD using the High-Resolution Rapid Refresh (HRRR). The blending algorithms, which have been developed at NCAR/RAL include three main components: (1) calibration of model forecasts; (2) correction of model position error; and (3) heuristic weighting of forecast inputs. Details of these algorithms will be given along with a summary of their performance during the summer 2010 operational evaluation. Improvements to be implemented in the summer 2011 will be described along with an assessment of expected and actual increases in skill. The main algorithmic change being assessed in 2011 is the use of regionally-varying and continually-updating enhancements to the calibration and heuristic weighting. This upgrade involves continuously assessing the performance of both extrapolation and HRRR forecasts and updating the bias correction functions and heuristic weights as needed. Results will show the improvements in skill associated with the enhancements both individually and combined. Preliminary results indicate a significant improvement in the bias at longer leads and in the skill of the forecasts greater than 3 hours.

“This research is in response to requirements and funding by the Federal Aviation Administration (FAA).The views expressed are those of the authors and do not necessarily represent the official policy or position of the FAA.”