Eclipse Weather: Too Early For A Forecast


9am Tuesday

Have you seen a weather “forecast” or two for the eclipse?  There’s NO ONE that knows what it’s going to do on eclipse day yet.  If you’ve seen one of these, keep in mind it’s just a grab for clicks (online clickbait) or viewers (TV eyeballs) and has no basis in meteorology.

We won’t have a general idea of possible rain that day until around 7-9 days out.  As for cloud cover, which is far tougher to predict, we’ll start taking a stab at it this coming Sunday which will just be a general guess, and then hone in on a detailed forecast during the week leading up to the event itself on Monday the 21st.  Trust me, forecasting low marine clouds west of the Cascades is something we can easily get wrong just 3 days ahead of time.

As mentioned in the previous post, we DO have models that go out two full weeks like the GFS and ECMWF often referenced here.  But the “operational” versions of these models can flip around wildly with each run that comes in.  For example the 0z (evening run) GFS model looked like this on eclipse day:


That’s a cold upper-level trough just like we see in May or June.  That’s a showery and cool setup, but even in this pattern you can get large breaks in the cloud cover.  But wait!  6 hours later the overnight run of the GFS came in like this:

gfs_namer_324_500_vort_ht (1)

Much better, patchy morning clouds MAYBE west of the Cascades, otherwise all sunny and a very settled summer pattern with highs at least in the 80s.  In this model the trough is way up in SE Alaska.  You see the problem and why it would be ridiculous to make a forecast more than a week in advance?

That said, just as I mentioned in the last post, at least part of NEXT WEEK DOES FEATURE  A RARE COOL AND SHOWERY WEATHER PATTERN FOR MID AUGUST.  36 of 51 ECMWF model ensemble members (over 50%) project at least a tenth of an inch of rain over the metro area between now and eclipse day.  Some give us a half-inch or more.


Yet once again there is no need to panic…for now.  Take a look at 24hr rain totals from the same ensemble members:


You see a good percentage of the “rain action” happens Monday-Thursday next week.  There is a secondary smaller spike around the 21st/22nd (eclipse day), but only 7 of 51 ensemble members show more than .05″.  And this says very little about cloud cover, which of course is all we care about at 10:18am Monday the 21st.  Again, we won’t be able to start working on that one until about a week out.

To wrap it up, there is no need to panic/worry at this point.  We’ve got you covered here at FOX12; ignore any other “forecasts” you see in the next 5-6 days.  I’m right with all the rest of you watching the cloud forecast VERY carefully starting this coming Sunday/Monday!

Chief Meteorologist Mark Nelsen

51 Responses to Eclipse Weather: Too Early For A Forecast

  1. W7ENK says:

    SPC has the Eastern portions of the Willamette Valley/PDX metro area under TSTM risk next three days.

    Day 1:

    Day 2:

    Day 3:

  2. JERAT416 says:

    I’m not ready for multiple days of rain. However, I’m ready for September weather. crispy mornings in the 40’s, highs in the 80’s with it cooling down again before 4.

    • Roland Derksen says:

      I’m only expecting one, possibly one and a half days with rain here. That’s enough for now- hopefully it will clear away the smoke. I miss seeing the mountains!

    • Joshua Downtown PDX says:

      What rain?

    • Roland Derksen says:

      Joshua, I’m referring to the forecasted rain here this weekend.

    • Joshua Downtown PDX says:

      Roland, I was referring to JERAT’s comment. Portland’s “rain” in the coming week will be extremely meager in a best-case scenario. We will be lucky to eek out .01″ to end the dry streak.

    • Joshua Downtown PDX says:

      Gotcha. I’m ready for rain. Lots and lots of it.

  3. Erika says:

    I could care less for the the eclipse, I’m tired of this heat, I want cool weather already, I can’t wait for clouds and showers and thunderstorms!

  4. Mitchell, in Wheeler County, is near the path of totality and so is most of the John Day Fossil Beds. I wonder how many people will be out there for the eclipse? Even at its worst, I’m sure whatever crowds are out there will be eclipsed by the masses of humanity descending on Salem and Lincoln City.

    • …there is a festival with 30,000 people near there, along with every town having a celebration of some sort….i think there’ll be more masses of humanity in eastern oregon than anywhere else in the state due to the chances of clear weather being better over here….

    • I’m going to be in Grant County, dispersed camping in the Malheur National Forest 10 miles from the nearest paved road. (I hate mob scenes, can you tell?)

    • W7ENK says:

      We won’t be too far apart, Rubus. I’ll be just a handful of miles from you in SW Baker County.

  5. Jason Hougak says:

    Seems there are more of us don’t want the eclipse to happen. I think it’d be spectacular but the crowds of people, traffic, smoke, heat, fires are really making me want it to pour down rain instead and get this place green again.

  6. Jason Hougak says:

    Well there goes my plan for viewing the eclipse from Mt. Jefferson as forest fire officials say the Whitewater Fire will not be out in time for the eclipse and the area will remain closed. The PNW badly need some torrential downpours now to put that damn fire out!!!

  7. Is it wrong that I sort of want clouds to move in across the path of totality about an hour before the eclipse?

    • JERAT416 says:

      I prefer us to be socked in from the night before through the whole eclipse day. Why? To make it so traffic in the valley isn’t like some post apocalyptic wasteland.

    • …the traffic scrambling to find a clear place if the forecast turns bad will be even worse than what will already happen without that monkey wrench in the works…

      • JERAT416 says:

        Then maybe I want to slap the people who write the articles about the eclipse and say “Just take the day off from work” like somehow that applies to more than a tiny percentage of people besides the elite rich. Yeah with every business super busy during that time and then you just don’t show? Yeah that’s a good way for employers to fire those who decide to not show.

    • gidrons says:

      What? Half the people at work took the day off and I guarantee none of them are rich.

      • JERAT416 says:

        At my work, only one person per department can take any given day off and someone already has that week off so I’m screwed. Anyone calling in would be obviously under the microscope. I don’t know any employer that has so many extra people that half can just not show up. Ok maybe a ski resort but I don’t know anyone at such a place. It’s a luxury that most people don’t enjoy. I work in one of the industries that is gonna be insanely busy during that time.

    • W7ENK says:

      If traffic is even a fraction as bad as is being predicted, folks may not even be able to get to work that morning.

      FWIW, I scheduled my PTO for August 21 and 22 back on January 3rd!

      • JERAT416 says:

        Thankfully I don’t work weekends but even if I had asked for that day at the beginning of the year, I might not have gotten it. Morning will probably be ok but afternoon will be adult male cow excrement…..

    • gidrons says:

      I guess I’m lucky to be working where I am then. The owners know this could be a once in a lifetime event for some of us, and haven’t denied anyone that I know of.

  8. All the more reason to tilt the odds in my favor and be east of the Cascades on Eclipse Day.

  9. Jason Hougak says:

    I’ve had enough of this horrible air quality

  10. W7ENK says:

    You know, this heat wave we just endured was showing in the models two weeks out, and no one really wanted to believe it… and then it happened.

    The big snow we got last January was showing in the models two weeks out, and no one really wanted to believe it… and then it happened.

    Huge soaking rains on eclipse day showing in the models two weeks out, and no one really wants to believe it…

    • muxpux (Longview) says:

      Yeah well, 2 weeks ago these last two weeks were supposed to be 8 days of 100+

      I’ve seen models say 2 feet of snow, or -5.

      A broken clock is right twice a day.

      And while yes, the models can be right about something 2 weeks out thanks to the laws of probability, the small details are hardly correct.

      Remember how we were supposed to break the streak of 90+? Even the day before they were expecting to. Even the morning of.

      Things happen, the weather is dynamic and always changing. For a model to be 100% right, is just dumb luck.

    • ocpaul says:

      I predict, that on Eclipse Day 2017, the moon will block the sun for a short period. Am I wrong? Any wagers?

    • Oh you’re definitely wrong. A geological period lasts for millions of years. Just a few days without the sun would devastate life on Earth. Cutting two or three million years out a period would make no difference. Or did you mean a girl’s period? Google says that normally 3 to 5 days, but can be as short as two days. Two days might not be too bad for all life on Earth, but we’d definitely experience some awesome record lows and ferocious winds due to the absence of sunlight.

  11. W7ENK says:

    Oh, wouldn’t that just be hilarious… 😡

    • Mark Nelsen says:

      I agree, it would almost be worth missing out on it just to see how cranky we all get about it.

    • I would half-expect riots to break out if that happens.

    • Also, given how stupid some people are today, I wonder if weathermen would get hatemail for a forecast bust on eclipse day. I guess that would make an interesting blog post, though.

    • W7ENK says:

      Well, considering I’ve literally been waiting since my early childhood for this soon-to-come two minute window, I would personally be devastated. My plan to watch from a mountaintop in far Eastern Oregon may become a really early morning mad dash into Idaho, or even Wyoming if need be — however far it takes to find a hole in the clouds. My fingers are crossed that this won’t become necessary, but if the high desert is covered with blowoff from thunderstorms the night before, or (God forbid) a stratiform rain band? Let’s just hope none of that happens.

    • @W7, I’m hoping to not have to make a last-minute road trip to ID or WY, either.

    • In fact, if Eastern Oregon does get clouded out, enough folks will probably be doing the last minute road trip thing as to collectively interfere with each other’s goal of being in Idaho on a short notice (can you say “traffic congestion”, boys and girls). I really think this whole thing is a “you stake your claim to a spot to watch it, and you take your chances” sort of thing. That’s why I chose to maximize those chances by going east.

    • W7ENK says:


      Best I can really do is stick with the plan and pray that the Universe doesn’t kick me square in the balls, I suppose…

    • …hoping that mad dash isn’t needed!!!!!!!!

    • At least the Universe saw fit to schedule this eclipse for August, so both the odds and the personal comfort factor are vastly better than if this event was happening in, say, January.

    • yea….the last one in ’79 was under rainy/snowy/rainy skies in NE oregon…

    • gidrons says:

      I’m with you on this one Erik. If I miss it, then its a road trip to Texas in 7 years.

  12. JERAT416 says:

    Exactly, we need to sit tight until we get closer. Wise words Mark!

  13. Roland Derksen says:

    60% chance of showers in my area on Saturday into Sunday. That usually means some measurable amounts, but not a soaking rain.It’s rare to see more than half an inch in a day in the first half of August, even at my latitude or higher.

  14. Joshua Downtown PDX says:

    I was going to comment about Rod after watching his forecast yesterday. I think he is being irresponsible. It’s fun to speculate, but a LOT of people have a LOT riding on this, so it’s best to make predictions based on a reasonable degree of certainty. He also called for soaking rain on Monday.

  15. Paul D says:

    U DA MAN Mark! Why would we go anywhere else for our forecast. I ain’t worried – just bring on some cooler temps and rain next week – it’s time to bring this dry spell to an end!

  16. You go Mark keep that pesky Rod Hill is his place he was going nuts yesterday about clouds and such for the big event. Glad you are keeping your cool.

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