Fire Weather Forecasting Support from the National Blend of Models

NOAA is establishing a foundational digital weather forecast capacity that supports a full spectrum of decision-making related to fire weather. In particular, the Meteorological Development Laboratory is working to transform existing weather forecast information into a probabilistic framework to support critical fire weather-related decisions made by the public, community, and partners. The National Blend of Models (NBM) is a nationally consistent and skillful set of calibrated forecast guidance based on a blend of both National Weather Service (NWS) and non-NWS numerical weather prediction data and post-processed model guidance. The goal of the NBM is to create a highly accurate starting point for the National Digital Forecast Database (NDFD) grids and support Impact-Based Decision Support Services (IDSS).

Numerous improvements will be made to Version 5.0 of the NBM in late 2025 in support of these goals. One of the major changes will be the addition of probabilistic fire weather elements for CONUS and Alaska and potentially Hawaii, Puerto Rico, and Guam. The NBM currently contains probabilistic and deterministic maximum (and minimum) temperatures, probabilistic and deterministic instantaneous and maximum wind speed and gust, and deterministic instantaneous temperature, dew point, and relative humidity. Version 5 will add probabilistic instantaneous temperature, dew point, and relative humidity, allowing for complete sets of percentiles for each of those elements, along with probabilities, including requested joint probabilities. It is envisioned that this improved service delivery will greatly support fire weather forecasting across time scales from hours to days.

This presentation will discuss the methodologies used to create the probabilistic fire weather output and explain the different types of products. Examples will be shown from relevant cases at various time ranges, and we will discuss efforts to evaluate the new products through collaboration with fire weather customers and stakeholders.