Weather models help predict if it's going to be sunny, rainy, or windy by looking at things like temperature and air pressure. This is helpful for us hikers because it can tell you the best days to hit the trails and when to stay home.
By switching models, you can compare forecasts, which means making sure you're safe and enjoying the great outdoors to the fullest!
TrekWeather uses two model families: a US bundle (NOAA's GFS + HRRR) and the Canadian GEM. Comparing them provides valuable insights since they make different assumptions and update on different schedules.
You don't pick between GFS and HRRR. When you choose the US option, we automatically blend them for you: HRRR provides the high-resolution detail wherever it covers you (continental US and Alaska), and GFS fills in the broader, longer-range outlook. You just pick US or Canada, and the right model takes over behind the scenes.
Environment Canada's Global Environmental Multiscale. Balanced global and regional forecasts.
Learn more →GFS: A global model with ~13 km resolution, providing a broad overview of weather patterns over large areas and longer forecast periods.
HRRR: Covers the continental US and Alaska with very high-resolution forecasts (~3 km). Updated hourly out to 18 hours, with extended runs out to 48 hours four times a day. Particularly useful for detailed, near-term weather predictions.
The Canadian GEM model offers both global (~15 km) and regional forecasts (~2.5 km HRDPS), with the regional version providing HRRR-comparable detail for Canada and surrounding areas. GEM updates twice a day vs. four times for GFS, so the two often disagree on near-term timing.
All three models incorporate a wide range of data, including satellite and radar observations, and employ sophisticated data assimilation techniques. HRRR, in particular, is updated hourly, reflecting the latest atmospheric conditions.
Each model employs different strategies to simulate physical processes such as cloud formation, precipitation, and land-surface interactions. These differences can lead to variations in forecast details, especially in complex terrains and for specific weather events like storms or heatwaves.
GFS: Forecasts up to 8 days, useful for trip planning.
HRRR: Detailed short-term forecasts, ideal for making last-minute decisions.
Provides a balance with both short-term and medium-range forecasts, allowing for flexible planning in Canada and potentially affected regions. Designed with a focus on Canadian geography and weather patterns for more precise regional predictions.
How TrekWeather uses these models:
TrekWeather combines the global NOAA GFS forecast with high-resolution HRRR forecasts. The GFS offers a broad perspective while the HRRR is specialized for detailed, imminent weather predictions, valuable for assessing sudden weather changes. Together, they enhance safety and preparedness by covering a wider range of possible weather conditions.
Yes! While the GEM model is designed with a focus on Canadian geography and weather patterns, it is a global model capable of generating forecasts for any location, including the U.S.
It may not have the same level of detail for specific U.S. regional weather phenomena as the NOAA GFS or HRRR models. However, GEM is still a valuable tool when used alongside other models to get a more comprehensive view of potential weather scenarios.