It is now just 4 days from the Eclipse. The Numerical models should be getting a better handle on the amount of clouds that will possibly interfere with Monday’s Eclipse show.
Looking at the GFS model which is the primary source of longer range forecast, there is still some concern that clouds will be an issue.
|Percent of cloud coverage forecast from the GFS model for noon Monday August 21 1917|
Another model to evaluate is the GEFS(ensemble GFS) which is a composite solution of running the GFS model given slightly differing initial conditions. Similar to a consensus opinion. This GEFS solution for mid day Monday provides a much more positive solution for the likelihood of interfering cloud cover.
GEFS forecast for percentage of cloud cover for noon Monday August 21 2017.
Again the forecasting of cloud cover in many ways is more difficult than precipitation 4 days ahead. However both forecast are encouraging that cloud cover will be limited on Monday over Wyoming and Southern Idaho.