Ensemble Trajectories

Ensemble Trajectories Tool

Easy computation of trajectories from locations within CONUS.

Designed to allow for use of multiple numeric weather models. Currently default is the National Weather Service’s NAM model at 12-km resolution. Additional meteorological grids from the CANSAC 2 km model, the NWRMC 1.33 km model, and the National Weather Service's NAM 3 km model are being incorporated at this time.


Tools are provided for research purposes only, and may not accurately reflect what happened/will happen due to numerous reasons. Data are provisional and subject to change. Use at own risk.

Tool Links

Stable URL:

Current Version:

Training Version:


This tool works best under Google Chrome. Internet Explorer / Edge browsers in particular may have issues and features are not guaranteed to work.

Known Issues / Current Development

    • Additional meteorological grids to be added

      • DRI 2km, NAM 3km


Air Resource Advisors should post questions / issues to the WFAQRP > #tools channel.

External inquiries regarding the Ensemble Trajectories tool should be directed to Dr. Sim Larkin, USFS-AirFire, larkin (at) fs.fed.us.


While the overall entry of information is simple for the ensemble trajectories, understanding the user interface requires some understanding. Please see the walkthrough below to see where to enter information and how to adjust what is shown in the output.

Ensemble-Trajectories-v2-Walkthrough for ARAs


The Ensemble Trajectories tool is developed by the USFS AirFire Team in conjunction with the University of Washington's School of Environmental and Forestry Sciences (UW SEFS), and is based on previous work with Mazama Science.

    • Concept and Project Lead: Sim Larkin, USFS AirFire

    • Lead Developer: Joel Dubowy, UW SEFS

    • Past Development: Mazama Science

Funding for the Ensemble Trajectories tool is provided by the USFS.

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