VAWS: High-resolution forecasting of wildfire activity and smoke: The High-Resolution Rapid Refresh (HRRR) model

Speaker: Eric James, NOAA Global Systems Laboratory

Beginning with the implementation of the latest version in Dec 2020, NOAA’s High-Resolution Rapid Refresh (HRRR) model now includes operational prediction of smoke from wildfires. The model simulates smoke from wildland fires in real time with 3-km grid spacing over CONUS and Alaska domains. The modeling system estimates biomass burning emissions and simulates fire plume rise in an inline mode by using the fire radiative power data from the VIIRS (onboard S-NPP and NOAA-20) and MODIS (Terra and Aqua) satellite instruments. The model includes the direct feedback of smoke on radiation, as well as the impact of smoke on near-surface visibility. In this presentation, we describe the model configuration, and show results from retrospective simulations during recent years.

We also describe recent work to develop a novel fire weather index, referred to as the Hourly Wildfire Potential (HWP), which is intended for application to a convection-allowing model like the HRRR. The HRRR’s ability to represent convective storms and their outflows, as well as its treatment of land surface processes within the RUC Land Surface Model, allows for forecasts of wildfire activity in the next 1-2 days. The HWP index is able to capture a portion of the weather-related variability in fire behavior, in particular the changes in activity related to synoptic and mesoscale wind events, as well as rainfall and snowfall. Comparison with existing fire weather indices illustrates the ability of the HWP index to highlight fire weather conditions and rapidly-changing fire weather. Real-time HWP index forecasts are now being produced for CONUS and Alaska based on the operational HRRR, and for North America based on the experimental Rapid Refresh Forecast System (RRFS), slated to replace the HRRR in operations in several years. This development also paves the way for improved prediction of wildfire smoke emissions in the coming hours and days.

The Virtual Alaska Weather Symposium (VAWS) is a collaboration between ACCAP, the Geographic Information Network of Alaska, and the NOAA National Weather Service. We present cutting-edge technologies in satellite remote sensing, forecasting, and modeling to a statewide audience through this webinar series.

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