Weather odds not in our favor for seeing the solar eclipse in Seattle
If you were to draw up a perfect day for a total solar eclipse in the Pacific Northwest with the best chances to actually see it, August 21 would certainly be among the top choices. We're square in the region's dry season, with only about a 20 percent chance of a rainy day in any given year.
Lo and behold, the star (and planet and moon) are aligning on that date. But that fortunate timing on the calendar might still not be enough for those of us living in and near some of the cloudiest cities in the United States to see it, because the timing of the day -- just after 10 a.m. -- is not the best.
For areas like Seattle, Portland and Western Washington/Oregon, the main weather wrinkle in summer is the potential for morning clouds, courtesy of our frequent ocean breezes that blow the ocean fog and low clouds inland. Sure, it keeps temperatures from getting too hot, but the flip side is, depending on the weather setup that morning, it could ruin a once-in-decades chance to see an eclipse in your own area.
NOAA has calculated what many cities' historical chances are for seeing the eclipse based on the past 30 years of data, and the numbers are dicey for Seattle: We generally have a less than 50 percent of having clear enough skies to see the eclipse.
Specifically, Seattle has a 59.2 percent chance of having the skies at least 5/8ths obscured, with 28 percent chance of total overcast. We have another 12.9 percent chance of skies being partly cloudy, and only a 28.1 percent chance of clear to mostly clear skies. Meh. (If only the eclipse were later in the day! Our odds would improve to only 44.4 percent chance of mostly cloudy-to-overcast skies in the mid afternoon because by on most days, any marine layer would have burned off.)
But Seattle wasn't in the path of totality anyway. The moon will obscure about 92 percent of the sun here -- very cool for sure, but not THE FULL show. No, everyone who wants to see the complete show is heading to northern and central Oregon where the total eclipse can be seen.
If you were thinking Portland, which is just outside the totality path, the odds of dodging the marine layer are a bit better -- about 50/50 chance of whether skies will be clear enough.
Salem is even a better choice as it's in line for the full total eclipse. And its odds of seeing the show are 53 percent clear, 8 percent partly cloudy and just under a 39 percent chance of being all mostly or all cloudy.
But the best choice of all is to go east of the Cascades, which act like a barrier to the marine layer. Most have already figured this out and good luck finding a hotel or campground along the path of totality in Eastern Oregon.
Yes, the early birds were wise. Pendleton, which is not in the path of totality, but is the closest city to the path of which there is 30-year data available, boats a 75 percent chance of clear or mostly clear skies and just a 19 percent chance of being clouded out.
(And on the flip side, just...don't go the coast. Only about a 30 percent historical chance of having a clear morning there. Unless you figure there won't be any crowds and you want to play the underdog -- Newport, Oregon is in the path of totality.)
Again, this is all based on historical data, and not an actual prediction of what this year's August 21st will be like -- still way too early to know that for sure.
What about other cities?
What I've shown is the past 30 years of data. However, NOAA has gone back and calculated additional cities based on 10 years of data since some of the smaller cities began better tracking cloud data in 1998.
"This 10-year timeframe allowed hourly normals computation for more than 800 stations," NOAA said.
They've created an interactive map that overlays where the path of totality is. Again, Eastern Oregon is your best bet, if you can find a spot.
However, these smaller stations come with a bit more of a caveat:
"Automated weather stations only view clouds from the surface to 12,000 feet. Larger airports also typically have two cloud sensors (ceilometers) whereas smaller airports may only have one. Larger airports often have human observers that can see higher clouds," NOAA says. "These differences mean that stations at larger airports tend to detect more clouds, so stations near each other may report different viewability percentages."
And if by chance Mother Nature fouls up everything with an ill-timed low pressure system, you can still watch the eclipse live on a NASA web stream.
More Information, plus safe viewing tips: