https://www.washingtonpost.com/news/capital-weather-gang/wp/2017/08/20/total-solar-eclipse-weather-forecast-as-of-aug-18/?utm_term=.b54a9532ae66 wrote:
Capital Weather Gang
Total solar eclipse weather forecast as of Aug. 20
By Matt Rogers August 20 at 10:40 AM
<<The eclipse is just a day away, and our confidence in the forecast continues to grow. We wish that it could be clear across the entire United States for this awesome event, but unfortunately there will be clouds in many places, including along the path of totality.
In the southern Midwest, be prepared to drive to identify better viewing; high cloud cover present here may allow for some less obstructed viewing.
Generally, the West is still best, but scattered smoke and haze issues are difficult to predict.
Forecast confidence: Medium to high
Corvallis, Ore.: Morning fog likely to burn off in time for good view
Madras, Ore.: Mostly clear but light smoke or haze possible
Rexburg, Idaho: Scattered clouds, light haze or smoke possible
Casper, Wyo.: Mostly sunny, smoke possible, limited interference
Grand Island, Neb.: Partly cloudy, frequent interference possible
St. Joseph, Mo.: Partly cloudy, frequent interference possible
St. Louis: Partly cloudy, occasional interference possible
Carbondale, Ill.: Partly cloudy, occasional interference possible
Hopkinsville, Ky.: Partly cloudy, occasional interference possible
Nashville: Scattered clouds, limited interference
Forecast confidence: Medium
Greenville, S.C.: Partly to mostly cloudy, occasional to frequent interference
Columbia, S.C.: Partly to mostly cloudy, occasional to frequent interference
Charleston: Partly to mostly cloudy, frequent interference possible
Finally, note that the above maps display the model forecasts for total cloud cover, which take into account both high and low clouds. In some areas, their illustration is probably overly pessimistic because the eclipse may still be viewable through high, thin clouds.
The timing of the eclipse is ideal, at least for the West. It begins just after 10 a.m. local time on the West Coast, which is usually enough time to burn off the fog that often occurs there.
The intermountain areas sometimes see thunderstorms bubble up in the afternoons during this time of year. These are associated with the Southwest monsoon, a period of increased thunderstorms and rain during the late summer and early fall. But the eclipse passes through this region around noon, before most of the storms develop, so the storm risk should be low there.
Clouds often pop up along the rest of the path throughout the day simply because of warmth and moisture. Those two things combined lead to rising air, which creates clouds. So the cloud risk gets greater the farther east you go. On top of that, South Carolina will see totality the latest in the day — after 2:30 p.m.>>