Assimilation of All-Sky Water Vapor Channel GOES-16 Radiances into the Warn-on-Forecast System

With the operational availability of GOES-16 ABI data and the increasing maturity of the Warn-on-Forecast system (WOFS), a comprehensive analysis of the relative impacts of assimilating GOES-16 all-sky water vapor channel (6.2, 6.9, and 7.3 um) radiances compared to other radar and satellite observations can be undertaken. The current iteration of the system relies on cloud property retrievals, which have proven to increase forecast skill of high impact weather events compared to only assimilating radar and other conventional observations. The impacts of assimilating clear-sky radiances have previously been explored and shown to provide useful information on mid-tropospheric moisture content in the near storm environment. Assimilation of all-sky radiances adds a layer of complexity and various techniques are tested to determine the most effective across several events occurring in May 2019.

Qualitative and object based verification of severe weather and the near-storm environment will be used to assess the impact of assimilating all-sky radiances compared to the current model configuration. One of the challenges in these comparisons is that an improved forecast in storm rotation may not always correspond to an improved forecast in the near-storm environment. Balancing the impacts of each observation type to have an overall positive impact is the goal. We will focus our study through the entire WOFS analysis and forecasting cycle (1900 – 0600 UTC, daily) so that the impacts throughout the evolution of convection from convective initiation to large upscale growth can be assessed.