Daily forecasts are generated from the U.S. National Weather Service’s Global Forecast System (GFS) model runs. Trajectories are released every 3 hours from every GFS land grid cell in the U.S. and Canada for North America, and between 38N and the Arctic Circle elsewhere, at the same starting heights as the climatological runs and run out for 4 days. Interpretation of the daily forecasts is based on which height levels reach the Arctic.
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Tools are provided for research purposes only, and may not accurately reflect what may happen due to numerous reasons. Data are provisional; use at own risk.