Infusion of New Blending Technology into the NextGen Weather Processor for Improved Short-Term Storm Forecasting

The blending technology that will be used within the NextGen Weather Processor (NWP) to transition from a heuristic extrapolation forecast (which includes logic for storm growth and initiation) to the NOAA/NCEP HRRR (High Resolution Rapid Refresh) has recently been upgraded. This latest upgrade package was delivered to the FAA AJM-33 for installation as part of the NWP in August 2018. This new code release includes major upgrades that enable a 5-min update rate (instead of 15 min) of the 0-8 hour forecast, preservation of heuristic extrapolation forecasts in regions of nowcasted storm initiation and growth, and earlier introduction of HRRR-predicted convection initiation and growth using storm forecast uncertainty information. Methods for producing the blended forecasts have been modified such that the 1-2 hour blended forecast has been expanded to cover the entire domain spanned by MIT/LL NWP’s expanded CONUS (CONUS+) and has an outlook resolution of 5 min as in the Corridor Integrated Weather System (CIWS). This was done to preserve the look and feel of CIWS while enabling earlier introduction of modeled storm growth and initiation where indicated by the HRRR. Beyond two hours, the blended forecast domain region reverts to that defined by the HRRR with an outlook resolution of 15 min.

The new forecast system has undergone extensive testing and comparison with the previous version of blending that was delivered in January 2018 and with CoSPA, which has been in use as a supplemental source of short-term weather forecast information by the Aviation Weather Center, the FAA’s Air Route Traffic Control Centers (ARTCCs), the FAA’s National Command Center and airlines for several years. This new version significantly reduces the discontinuity between 2 and 2.25 hour forecasts seen in these older systems while showing significant increases in skill for lead times between 1.5 and 4 hours. Current status and timeline for full implementation of the new blending technologies into the NextGen Weather Processor will be given.

Disclaimer: 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.