By Katy Galimberti, AccuWeather staff writer
It's been 40 years since a total solar eclipse was visible in the continental United States.On Monday, Aug. 21, the event that millions have anticipated will unfold when the moon passes directly in front of the sun.
The path of totality stretches from Lincoln Beach, Oregon, to Charleston, South Carolina. In this swath, the moon will completely cover the sun. When this occurs, the sun's atmosphere, known as the corona, will be visible.
Outside of the path of totality, observers will see a partial eclipse.
However, storms and clouds may spoil the view for some.
"In the summertime, there is always the risk of a patch of clouds or a pop-up thunderstorm spoiling the view of the sky," AccuWeather Senior Meteorologist Alex Sosnowski said.
"Patchy fair weather clouds are most likely in the humid regions of the East and South and over the mountains in the West," he said. "But, there will be some exceptions on Monday."
Morning low clouds from the Pacific Ocean could fill skies in coastal areas of Washington, Oregon and California.
Smoke and haze from wildfires could also take the edge off viewing conditions across the Northwest. Eclipse revelers should heed all mandatory evacuation orders and not venture into fire danger areas.
AccuWeather Senior Meteorologist Dave Samuhel said some of best cloud-free conditions will extend from interior Oregon and California to Idaho and Wyoming, despite any haze from distant fires.
Over the interior Southwest, the timing of the eclipse will help in terms of cloud cover, according to AccuWeather Senior Meteorologist John Feerick.
"There will continue to be some moisture in place over the Southwest, but the eclipse occurs there a little earlier in the day and most of the thunderstorms are likely to occur in the afternoon," Feerick said.
Across the interior Southwest, the bulk of the morning clouds will extend from eastern New Mexico to southeastern Colorado and southwestern Kansas.
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Along the path of totality from southeastern Missouri to much of Tennessee, conditions will be ideal.
Conditions are likely to be mostly clear for the partial eclipse from much of the immediate Ohio Valley to part of the mid-Atlantic and southern New England.
Showers and thunderstorms are most likely in the southeastern corner of the nation due to a batch of tropical moisture.
Fortunately, no widespread area looks to be overcast the entire time, even from northern Florida to coastal areas of the Carolinas.
An overcast sky may obscure the partial eclipse across a large portion of the Upper Midwest and central Plains. In addition, severe weather will threaten this region.
Cloud cover and thunderstorms attributed to a tropical feature dubbed 92L will affect Hispaniola, the Bahamas and part of Cuba on Monday.