Eclipse 2017: What happens if it’s cloudy on Aug. 21? | News | The Press and Standard
by The Press and Standard | August 10, 2017 5:00 am
Last Updated: August 9, 2017 at 10:01 am
What’s the forecast?
The only uncertainty concerning the Aug. 21 eclipse is whether the weather will allow us to see it.
Several organizations offering long-range weather forecasts agree that rain and clouds are possible on Aug. 21, but differ on the severity of the rain and cloud cover.
On Aug. 21, all of North America will view — weather permitting — a partial eclipse, when the moon obscures part of the sun.
• A total eclipse will be viewable throughout a 70-mile-wide path that crosses 14 states from Oregon to South Carolina.
• The umbra (or dark inner shadow) of the moon will be traveling from west to east at almost 3,000 miles per hour (in western Oregon) to 1,500 miles per hour in South Carolina.
• The last total eclipse in the United States occurred on Feb. 26, 1979. The last total eclipse that crossed the entire continent occurred on June 8, 1918.
• The last time a total solar eclipse occurred exclusively in the U.S. was in 1778.
• Experiencing a total solar eclipse where you live happens on average about once in 375 years.
• 12.2 million Americans live in the path of the total eclipse. Of course, with visitors, that number will be much higher on Aug. 21.
• About 200 million people (a little less than two-thirds the nation’s population) live within one day’s drive of the path of this total eclipse. In addition, millions of Americans will be able to view a partial eclipse, weather permitting.
• The lunar shadow enters the West Coast at 9:05 a.m. PDT, and Lincoln City, Oregon will be the first place in the continental U.S. to see the total solar eclipse, beginning at 10:15 a.m. PDT.
• Carbondale, Ill., will experience the longest eclipse duration, clocking in at two minutes, 43 seconds, beginning at 1:20 p.m. CDT.
• Hopkinsville, Ky., will view the greatest eclipse — that is, where the sun, the moon and Earth line up the most precisely. The eclipse begins there at 1:24 p.m. CDT.
• Charleston, S.C., will be the last place in the continental U.S. to see the total solar eclipse, ending at 2:48 p.m. EDT.
• The lunar shadow will exit the East Coast of the U.S. at 4:09 p.m. EDT.
• Eleven spacecraft, over 50 NASA-funded high-altitude balloons, numerous ground-based observations and citizen scientists will capture a wealth of images and data that will be made available to the public before, during, and after the eclipse.
• Total solar eclipses offer unprecedented opportunities to study Earth under uncommon conditions. The sudden blocking of the sun during an eclipse reduces the sunlight energy that reaches the Earth. Scientists stationed in Columbia, Missouri and Casper, Wyo., will measure the radiant energy in the atmosphere from the ground and in space. Their goal is to improve our understanding of how the sun’s radiant energy within the Earth’s atmosphere changes when clouds, particles, or the moon block sunlight from reaching the Earth’s surface.
• Scientists have made extensive atmospheric radiant energy measurements during eclipses before, but this is the first opportunity to have coordinated data from both the ground and from a spacecraft located one million miles (1.6 million kilometers) from Earth that can see the entire sunlit Earth during an eclipse.
• These quick-changing conditions can affect local weather and even animal behavior. For example, orb-weaving spiders were observed dismantling their webs during a 1991 eclipse in Mexico.