Sunday Evening Eclipse: Clear Sky Expected

There will be a total lunar eclipse at a convenient time along with clear skies…what could be better?

Sunday evening we’ll be treated to not only a total lunar eclipse (not TOO uncommon), but a “super” moon at the same time.  That hasn’t happened in many years.  What does it mean?  A good evening to go outside and check out the sky.

A total lunar eclipse happens when our shadow passes over the moon.  That means if you are on the moon you would see earth passing in front of the sun.  The progression is something like this image from Sky & Telescope magazine:


In the case of Sunday evening, the eclipse will have almost reached totality when the moon rises over the Cascades (when viewed from the western valleys of OR/WA).  Then just 15 minutes later we’ll be in totality…for the next hour and 12 minutes.


After that time a bright slice of the moon will appear and gradually grow larger over the following hour or so as things return to normal.  So what about the SUPER part?  Well, there’s a bunch of media drama there because it’ll barely be noticeable as this graphic shows:


There is a 14% size difference between full moons.  I bet you didn’t know that!  It’s because the orbit around the earth is slightly elliptical, not a perfect circle.  The difference between the closest and farthest moon locations is only 30,000 miles, so our eyes can’t even tell the difference from one full moon to the next.  It’s interesting to note that the term SUPER MOON existed from the last 1970s to the late 2000s, but hardly anyone had heard about it until 2011 when the media picked up on it.

Finally, it is sometimes called the “Blood Moon” because of a reddish hue during totality.  That’s due to light from earth’s atmosphere filtering onto the surface of the moon.


The weather looks excellent Sunday evening with mainly or all clear skies across the entire Pacific Northwest.  Enjoy the show!

A far more detailed explanation of all this is at Sky and Telescope’s web site.  It’s a great one to bookmark for future events.

Chief Meteorologist Mark Nelsen

30 Responses to Sunday Evening Eclipse: Clear Sky Expected

  1. I first got a glimpse of the moon just after 8pm here. It was briefly blocked from view by a tall tree in the neighbourhood, but for most of the past half hour I could see it from my bedroom window. Very Nice!

  2. Jason Hougak says:

    What a great night to be a pilot

  3. Jason Hougak says:

    This is pretty remarkable👍👍

  4. High Desert Mat says:

    Cant wait for your pics of the eclipse Tyler!!!!! We know they’re coming.

  5. High Desert Mat says:

    Seen the eclipse for past half hour. Looks like a creepy Sci fi movie. I hope I don’t have another vivid dream. Two weeks ago I dreamt that the moon was colliding with the earth. Strange I know but it seemed all too real. Anyways, the moon looks cool tonight. Here’s to a great fall, its getting really crisp outside. Go hawks.

  6. Paul D says:

    Eclipse finally visible in Hillsboro. Had to wait for it to clear the two story houses.

  7. vernonia1 says:

    what direction is/was the moon?

  8. David B. says:

    Was camping at Mt. Rainier for a few days (White River Campground). Was cloudy and damp for several days then cleared off late last night and got cold; morning dawned frosty. Back at home now and still completely clear. Looks like it’s showtime for the lunar eclipse.

  9. WEATHERDAN says:

    70 out now after a low of 40. Going for 74 today and 80 Monday and Tuesday. Breezy North winds and bright sunshine should make for a great eclipse this evening. Next two weeks look great. Mainly dry with highs in the seventies to near 80. Really great early Autumn weather. Had 1.13 inches of precipitation this month so far. Not a drought buster but enough to make me feel not guilty for enjoying this nice weather. Heavier rains will come in due time. Peace.

  10. Jason Hougak says:

    Had a cool evening under the full moon and a frosty morning in the foothills. Falls is here with brilliant color and great weather.

  11. Lee Wilson says:

    Might want to wear a coat.
    we got down to 32.3 last night and had frost on the roof tops.

  12. It was quite a sight seeing the moon last evening- perfectly clear skies at the time. Can hardly wait to see it this evening! Let’s hope these morning clouds disappear long before then.

  13. schmit44 says:

    9/26/2015 Oregon (All) Temperature Summary

    High:88 at ALKALI FLAT(2495 ft) & Ontario Municipa(2188 ft)
    Low: 66 at LAKE OWHEE AND O(2400 ft)

    High:49 at MT HOOD TEST SIT(5370 ft) & K7ZQU-7 Santiam(4790 ft)
    Low: 23 at CROW FLAT (5172 ft )

    Largest Diurnal Change: 49 degrees
    Lorella (79/30 ) (4160 ft )

  14. Garron (1/3 of a mile from the Hillsboro airport) says:

    Well, this explains why the moon appeared brighter during a super moon. What are the tide forecasts I wonder? Probably a really good time at the beach to collect sea shells I imagine!

  15. WEATHERDAN says:

    Got this today off the Accu Weather site today. It deals with El Nino.

    Are El Nino Years getting Warmer?
    September 26, 2015; 12:39 AM ET

    Below is the latest up to date NASA GISS plot of the global land/ocean surface temperature anomaly since 1880.

    It is looking more and more likely that 2015 will end up as the warmest year on record (currently held by 2014) thanks in part to a strengthening El Nino that is currently in the strong category coupled with a warm (positive) phase of the Pacific Decadal Oscillation (PDO).

    It is well known that El Nino has a warming influence on the overall global temperature. A positive PDO also seems to have a warming influence. Based on this and the fact that fourteen of the 15 hottest years on record have all fallen in the first 15 years of this century it is no real surprise that 2015 will likely set another record as underlying warming continues.

    What I did below was to first show a globally averaged temperature anomaly graph of just El Nino events going back to the 1950s. The start years of each ENSO event are shown for reference. Basically what I did was average out the monthly, global temperature anomalies (via NASA GISS) that were officially included under EL Nino criteria (via NOAA) whether it was a 4 month period or a 13 month El Nino period. The actual plot of anomalies is labeled in red with the upward trend line in green.

    As you can see, it is pretty obvious that El Nino years by themselves are getting progressively warmer over the past 60+ years. Why is that?

    A list of EL Nino events in the past 50 years by strength. Typically the stronger the El Nino the stronger the warming influence on overall global temperature.

    Next, I made a plot of years where there was an El Nino and a +PDO.

    Despite the smaller sample, it is pretty clear once again that years with an El Nino coupled with a +PDO are trending warmer and the most likely reason is the steady increase in greenhouse gas concentration, which is clearly causing an increase in heat which is mostly being absorbed by the oceans. The loss in sea ice in the Arctic is also contributing to the rapid increase in temperature in that region due to a decrease in albedo.

    The El Nino Southern Oscillation shows close correlation to global temperatures over the short term. However, it is unable to explain the long term warming trend over the past few decades.

    The PDO is an internal process and does not increase or decrease the total energy in the climate system.

    Yes, the strong EL Nino and the +PDO are have contributed to the record warmth so far in 2015, but it’s not the only story, far from it.
    The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or

    Pictures didn’t come through. Peace.

  16. Garron (1/3 of a mile from the Hillsboro airport) says:

    There are times that the moon appears MUCH brighter when it’s full. I once, around 1999-2000, drove to Seaside during a spring moon event just to walk on the beach at 3 am because there was a really high tide, followed by a really low tide. I hadn’t seen so many perfect seas shells on the beach since I was a kid! On the drive down, the moon was so bright, you could see just fine with the headlights off! Wonder what phenomena causes the moon to appear that much brighter? Cool post Mark, the werewolves will be out on Sunday!

    • Garron (1/3 of a mile from the Hillsboro airport) says:

      I should have said…”much brighter than a normal full moon event typically appears…”

  17. I’ll be down in Lincoln City!

  18. Boring Oregon says:

    Now that something cool in the sky is going to happen it’ll get cloudy and rainy so we can’t see it. Never fails.

  19. timbers15 says:

    Next chance to see something similar will be in 18 years. So, this is the best chance since we’ll have clear skies this weekend. Who knows how the weather will be in 18 years. Enjoy! Thank you, Mark for the complete information! Very professional as always.

  20. schmit44 says:

    9/25/2015 Oregon (All) Temperature Summary

    High:94 at Rye Valley(I-84(2229 ft)
    Low: 64 at DW9628 Richland(4046 ft)

    High:53 at TIDEWATER(2035 ft)
    Low: 23 at CROW FLAT (5172 ft )

    Largest Diurnal Change: 58 degrees
    Baker City Munic (89/31 ) (3373 ft )

    Heaviest Rainfall:
    0.39″ at KD7SYS-1 Dallas(413ft)
    0.34″ at k5vp Newberg(177ft)
    0.32″ at McMinnville Muni(157ft)
    0.32″ at EW4831 Portland(425ft)
    0.32″ at EW5295 Beaverton(775ft)
    0.31″ at EW1829 Tigard(176ft)

  21. …lucky me ;)…over here between baker and union with some mighty good easterly views close by!…methinks one of the pull offs on the road to anthony lakes might be a good place to be entertained…

    • Boydo3 N. Albany says:

      I’ll be on the coast, probably not so great, looking over the hill. But you sir, on the other hand, should have a great big view for sure!

  22. Jason Hougak says:

    Great sky watching, sounds exciting!

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