On Saturday, 13 June 2020 20:54:15 UTC+2, Bret Hess wrote:
It seems that NAM forecasts (12 km and 3 km) on XCSkies are very helpful for soaring in Utah. I haven't seen a benefit of HRRR over NAM. I'd be interested in hearing from other pilots who fly in the mountains comparing NAM with HRRR or Skysight for thermal predictions.

I'd also like to hear a discussion of why a 3 km resolution model is a great improvement for soaring over a 12 km model, for example. Higher resolution models generate more detailed forecasts, and maybe they show better what kind of variation you might see, but the variations at this scale don't seem pinned to the earth at an accuracy of 3 km.

You'll see detailed explanations in my talk above about resolution (https://www.youtube.com/watch?v=Ez9Xjo4llT8) including real world examples of the impact of resolution in the mountains. Over hilly or mountainous terrain the improvement from higher resolution can be significant. On flat terrain the influence is less, although if there's convergences or storms it may still be important.

Unless you're 4km or so you won't meaningfully resolve wave, convergences, or
convection. Instead you need to parameterize [ https://en.wikipedia.org/wiki/Parame...heric_modeling) ] the cumulus and convection, which has drawbacks.

I can't offer a comparison to NAM 3km or 12km, but I can show you the predicted tracks versus the route taken by Jim last week with their record flight (https://www.facebook.com/SkySight.io...type=3&theater)