An Eclipse is always a good opportunity for…SCIENCE!

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JPL 2017 Eclipse Simulator

Anyone want to know what the 2017 Eclipse will look like at your location with nice graphics and all? Check out this excellent simulator put together by NASA’s Jet Propulsion Laboratory. You’ll be able to animate the eclipse for any given location in the US from beginning to end and find out what to expect. I made a collection of some of the locations which will experience partial eclipses (all at their time of maximum eclipse). All these location were in areas of 75% or greater obscuration of the solar disk. Optical and atmospheric effects begin to take hold with 75% obscuration as incoming shortwave radiation from the sun is significantly reduced. Read more about that in my previous July post HERE if you haven’t already. Remember, however, that even with 99% obscuration, the sun will still be too bright and therefore too dangerous too look at directly without certified eclipse glasses. Direct viewing of the sun for multiple minutes can blind you, any amount can cause eye injury!

Seattle
Seattle, WA. My home city! 92% Obscuration.
Portland
Portland, OR. 99% Obscuration. So close to totality, yet so far!
San Francisco
San Francisco, CA. 75.5% Obscuration.
Denver
Denver, CO. 92% Obscuration.
Brookings
Brookings, SD. The location of my undergraduate alma mater South Dakota State University. 89% Obscuration.
Minneapolis
Minneapolis, MN. My Mom and much of my extended family lives here. They’ll take in the show. 83% Obscuration.
Dallas
Dallas, TX. 75% Obscuration.
Atlanta
Atlanta, GA. 97% Obscuration.
DC
Washington, DC. 81% Obscuration.
Jacksonville
Jacksonville, FL. 90.5% Obscuration.

Additional eclipse info for this post (such as max eclipse time) is courtesy of Xavier Jubier’s 2017 Total Eclipse Interactive Map.

Sky Conditions for August 21, 2017 Eclipse

The Great North American Eclipse is almost here! On Monday, the Moon’s inner shadow or umbra will touchdown over the open Pacific Ocean and rush toward a landfall in Oregon after 10:15 am PDT and exit the South Carolina Coast after 2:50 pm EDT. The shadow will be advancing across at around 1500-2000 mph. An incredible speed.

For an overview of the atmospheric phenomena to expect during the eclipse, see my previous late-July article on the August 21, 2017 Eclipse.

With the eclipse on Monday, the biggest concern is the weather…specifically sky conditions. The National Service, out of national interest in the eclipse (which will ONLY be seen in the United States) now has forecasts available, with special interest in sky condition forecasts.

Map
US National Weather Service Sky Condition Map (% sky cloud covered) valid 2 pm EDT Monday August 21st. Moon’s umbra will be over Nebraska at this time. 
Much of the eclipse path is *decent* (50% or less sky coverage forecast), although clear skies are extremely ideal. The best skies for totality are expected to be over the Northwest sector of the US, with greater cloud coverage (near 50% over the Central Plains/Missouri). There will be some improvement over Tennessee, but possible afternoon showers and thunderstorms may cloud up skies more significantly over extreme northeast Georgia and into South Carolina.

With that said…just remember…1) There’s more to the eclipse but totality! Regardless of whether you’re in the path or not, dealing with scattered clouds or not, enjoy the eclipse! Watch the crescents form in the shadows of trees, make a pinhole viewer (like this or this for example…I’m planning on making one!), if you have certified eclipse glasses or shades…safely observe the sun directly, and if you’re in a very deep partial (75%+) enjoy the effects of the weakening sun on temperature, sky and the animals. Also…2) For those in totality, all you need is that precious 1 or 2+ mins to be clear around the eclipsed sun. Hopefully, with that 50% or less sky coverage, that will be easier to achieve.


My Plans-

As you all may know, I live in Lincoln, NE…in the path of totality. As the city is literally on the northern edge of the shadow, there is a tight gradient for the length of totality; anywhere from tens of seconds on the north end of town, to 1 min 45 seconds on the south end of town. My house will see around 1 min 15 seconds. We had planned on going to Grand Island, NE about a hour and a half west of here to visit a relative of hers and see the eclipse at 2 min 35 sec (near max possible duration)…but our car has an issue which makes it not reliable for traveling on the highway! 😦 Literally found this out today! Extremely disappointed as there isn’t enough time for us to get the car fixed.  But considering we’re still IN totality vs. not, I can’t completely complain. So instead, we’ll be heading to the south end for the maximum length in Lincoln. I’ll have my GoPro set up on a mini-tripod to capture very high-res video of the last minutes before totality and during it. My fiance and I will also take lots of photographs. I will have updates on my Twitter and FB pages as the partial eclipse advances toward totality (feeds also can be seen from the website…but please follow me directly! 🙂 ).

It should be an exciting day! Everyone have safe viewing and have fun!

August 21, 2017 Eclipse is on its way! What to expect?

We’re now less than four weeks away from the historic total solar eclipse of August 21, 2017! This will be the first total solar eclipse in the contiguous United States since February 1979 when a total eclipse swept through northern Oregon, southern Washington, into Idaho, Montana and the Canadian Prairies. Much of the Northwest dealt with clouds in the coastal and western regions as cities such as Portland fell into a post-sunrise darkness.

Well now it’s 2017 and this eclipse is in a much better month…August. While this doesn’t guarantee good weather for any location along the path of totality; convection (thunderstorms) and cloud debris can cause issues on the Plains, while marine clouds can cause problems in the Pacific Northwest for example, generally quieter conditions with the jet stream and the domination of summer time high pressure and upper-air subsidence across the continent during the late summer means more opportunity for less cloud cover and quieter conditions across more parts of the country to view the eclipse in August than, say February.

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Path of umbra (inner lunar shadow) where totality will be observed as well as coverage of penumbra (outer shadow) where ONLY partial eclipse will be observed. The center line of the umbra will reach the Oregon Coast at ~17:16 UTC (1:16 pm EDT) moving at 2,416 mph and exit the South Carolina Coast at ~18:49 UTC (2:49 pm EDT) moving at 1,489 mph. ( map found on Wikipedia)
In order to assess the the most important aspect of observing an eclipse – sky conditions – the University of Idaho School of Natural Resources performed a climate analysis for the United States to determine the probability that a location will have clear skies at 10:30 am local time on August 21st. This time is picked because of the arrival of totality on the West Coast.

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Clear Sky Probability for the contiguous United States for 10:30 am local time August 21st. High probabilities are over portsions of the Western US, minus Western WA/OR and CA valleys where morning low marine clouds can occur. (U of Idaho College of Natural Resources)
While clear skies would be absolutely optimal for an eclipse, ESPECIALLY totality,  few to scattered cloud coverage (25-50%), while less fortunate in terms of direct solar photography and SAFE solar viewing, can still yield interesting observations leading up to and during totality. Because the umbra is quite thin, interesting atmospheric optics can occur. Although the area under totality becomes relatively dark, the light outside of the shadow can still be seen to observers. And the reflected light will appear to be twilight-like in color and glow. You could call it “eclipse twilight”. And with any cloud in the area, they will change colors or change in reflection of light as the darkness rolls over them, great for photographic and video effect. Just before totality, the sun itself will start to appear as if it’s “dying” in the final minute or two and the shadow will start to rapidly advance out of the western sky like a monster storm…except it’s not a storm 😀

In addition, regardless of scattered or no clouds, in the last min or so before (and after) totality, if you look at plain surfaces you may witness wavy motions like those in water known as shadow bands. These form as the focused, but rapidly weakening light of the sun is being distorted by the dense atmosphere of Earth. Those very near the totality path may also witness them.

This YouTube video I found some weeks ago shows both the prominent shadow bands and the “eclipse twilight” with clouds.

Now I’m a meteorologist. So when we talk about having a giant astronomical object blasting a shadow across a continent at 2000 mph and putting regions into nighttime in the middle of the day, a meteorologist is going to ask, how is this going to impact the weather?

For those at 75% percent partial eclipse and higher, the surface temperature will start to become depressed temporarily as the incoming solar radiation is reduced. This will be especially apparent for eclipses during the midday. As totality approaches, any winds may calm as a result of “fair weather convection” weakening as surface heating completely shuts down (this is where upward vertical motions produced by surface heating, leading to local winds die down).

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Here’s an EXCELLENT website using a Google Map layout where you can click on a location for eclipse “contact” times (start of partial, start and end of totality, end of partial) and maximum obscuration of the solar disk (areal coverage by the moon): HERE

In a couple weeks, numerical models will START to give us some distant idea of how the weather patterns may evolve for August 21st. I’m especially interested, because my location (Lincoln, NE) WILL experience totality. Will likely head to the south side of town to experience roughly 1 min 45 seconds of it and some of the very partial eclipse before that. It would be my first total solar eclipse since I was born and raised in Seattle but that event didn’t happen there and happened 5 yrs before I was born anyways.

Stay tuned in the coming weeks as weather updates come!