BOULDER, Colo. – A new tool from NOAA is the first to ever provide hourly updates on wildfire behavior, giving more accurate and timely predictions of wildfire activity.
The tool, called the Hourly Wildfire Potential Index (HWP) was developed by scientists at NOAA’s Global Systems Laboratory (GSL) in Boulder, Colorado, and the University of Colorado cooperative institute CIRES, based on three years of measurements of radiant heat captured by satellites flying over large wildfires in the western U.S., NOAA said.
It uses an experimental application of NOAA’s revolutionary High-Resolution Rapid Refresh forecast model (HRRR) and the next-generation Rapid Refresh Forecast System (RRFS), developed by GSL and the National Weather Service’s Environmental Modeling Center.
As years pass and wildfires have become a year-round issue in some parts of the country, more tools are needed to help give forecasters, land managers, emergency response officials and firefighters improved situational awareness of rapidly developing wildfire hazards, NOAA said.
HWP provides an assessment of wildfire potential based on model-predicted weather conditions and is updated hourly, even throughout the night.
NOAA’S NEW FLEET OF TINY OCEAN ROBOTS HELP STUDY TROPICAL ACTIVITY
This visualization displays conditions favorable for wildfire growth across the U.S. on August 21, 2025 at 5 pm MDT.
(NOAA Global Systems Laboratory / NOAA)
With hourly updates, HWP can forecast sudden increases or decreases in potential fire activity due to changing weather conditions like wind, cold fronts and rain, NOAA said.
“There are lots of existing fire weather indices, but the novel thing here is to be able to predict hourly variability in fire activity related to the weather conditions,” said Eric James, a GSL research physical scientist who played a key role in development of the HRRR. “Applying the HWP to a weather model like the HRRR provides an inexpensive way to anticipate changes in fire activity without running a computationally expensive fire behavior model.”
The HWP index incorporates predicted winds to estimate fire spread and intensity, humidity to estimate the influence of atmospheric dryness on fuel moisture, and soil moisture derived from the HRRR’s advanced land surface model to predict the response of flammable vegetation to precipitation and drought, according to NOAA.
Satellite imagery from NOAA’s GOES-18 shows the quick-moving Garnet Fire.
“We expect that this index can help forecasters anticipate sudden changes in wildfire activity, as well as predict wildfire smoke emissions, leading to improved decision support for fire management and enhanced communication with communities impacted by fire and smoke,” said James.
Real-time HWP forecasts are now being generated from operational and experimental storm-scale models covering the contiguous U.S. and Alaska, and are available on the GSL DESI website, NOAA said.
