Forecast not perfect for solar eclipseAug 17, 2017 By Katie Roenigk, Staff Writer
If the Great American Eclipse had been Wednesday or Thursday, local weather conditions would have made the Wind River Basin the perfect viewing location.
However, forecasters say current conditions aren't likely to remain through Monday - the actual day of the eclipse.
"It's not looking good," National Weather Service meteorologist Trevor LaVoie said Thursday. "It doesn't look like it's going to be a perfect, clear day like today. ... Right now it looks like there will be just enough clouds to be a nuisance."
The forecast anticipates that a weather system over the Great Basin will usher in monsoonal moisture Sunday from the south, LaVoie said; that moisture is expected take the form of scattered precipitation Sunday afternoon into Monday morning.
LaVoie said the southern system will likely combine with a cold front that will push clouds ahead of it from the north.
"(It's a) squeeze play, if you will, that's occurring," he said.
The timing of the cold front could change everything, LaVoie continued.
As of Thursday it was scheduled to enter Wyoming early Monday reaching the southern part of the state by midnight, meaning clear skies in the late afternoon and early evening.
If the front comes in earlier, the clear skies could appear during the day instead.
Of course, LaVoie noted, it's still a little early to be certain about the forecast.
"Right now the confidence is low to medium. ... Even what I'm seeing today is still changing from what we were seeing yesterday," he said. "Every day the confidence will get higher as we start narrowing that window, (and) we will be able to lock it down as we get closer to Monday."
But, he added, the prediction has been consistent for the past week.
"There's no fickleness in the forecast," he said. "The trend has been that there would be some sort of cloud coverage over the area. ... We haven't really seen anything to deviate from that."
An outlook released Thursday from the NWS showed a chance for showers and storms Monday afternoon over the western Wyoming mountains.
The cloud cover projection for noon Monday suggested 37 percent sky coverage for aRiverton, 43 percent for Lander and 46 percent for Dubois.
"All you need is one cloud to ruin everything," LaVoie said.
The model currently shows Oregon and western Idaho as the best locations for a cloud-free sky Monday.
"Pretty much all of Oregon looks like it's going to be prime," LaVoie said, "even going into extreme western portions of the Snake River Valley ... west of Boise."
There might be a hole in the sky over Guernsey and western Nebraska, too, but in general LaVoie said there will be a "stream of clouds" from Star Valley to Rapid City, S.D.
It's hard to know how the forecast will impact tourism over the weekend.
LaVoie pointed out that most people have already booked hotels or reserved campsites and likely won't be able to find lodging in other locations along the path of totality.
"There's probably going to be at least half that say, 'I made my reservation and I'm going to stick it out,'" LaVoie said, "versus those willing to take the gamble and go somewhere else."
Even if clouds cover up the sun during totality Monday, LaVoie said the sky will still darken when the moon blocks the sun. Eclipse viewers won't be able to see stars, though, or other associated light phenomena.
"With any kind of clouds it's going to be pretty difficult," he said. "But personally I'm just kind of interested to see how dark it gets. ... What will that look like when there's no sun? That in itself should be interesting."