January 26, 2022

Marvels of Fog and Low Clouds

Like many days this week, this morning dawned with low clouds and fog trapped under an inversion (see image for this morning).  Eastern Washington and interior western lowlands were pretty much covered in a thick blanket of white.

But although low clouds might seem unremarkable, there are subtleties to the observant eye that reveal much about our local meteorology.  And there is beauty there as well.

Take sunrise.  The visible satellite image taken just as the sun was coming up reveals the long shadow of Mount Rainier extending over the low clouds, like a dagger pointing to the northwest (see below).

The tip of the point is just south of Tacoma.

An hour later, the image around Hoquiam is revealing.   A narrow jet of fog is pushing westward into Grays Harbor.  And there are waves on the low clouds.  The fog exists in cold, dense air and this layer acts like a water body with waves undulating on its top.

And then there are the tendrils of fog moving up river valleys.  For example, higher pressure in eastern Washington is pushing fog/low clouds westward into Snoqualmie Pass and Steven Pass.  A good reason to take the lifts to the highest slopes available.

And satellite imagery reveals how fog burns off...something we didn't know about until we could view it from space.  Fog burns inward from its edges.  

You want to see?  Check out the imagery below for the Willamette Valley at 10 AM, noon, 1, 2, and 3 PM.

And perhaps the greatest treat is to hike above the low clouds into bright sunshine and to view the spectacular from aloft.   My plan for Saturday morning!


  1. We are on day 5 of non-stop fog now. Kind of fun and pretty eerie at night.

  2. Ice cold fog for 5 days.. definitely ready for a change!

  3. If it's July- it's smoke; If it's Dec/Jan, it's fog. The PNW's "new normal?"

  4. Cliff, on Tuesday I watched the fog erode from the center over the sound near Seattle. I'm wondering if you can comment on this, and if it has anything to do with the water? See this image as an example: https://atmos.uw.edu/images/vis1km_fog/202201252056.jpg

  5. Cliff, thanks so much for what you provide us with on your blog. In addition to a class in meteorology, we are treated to amazing photography, and I am reminded of what an astonishing planet we live on, and the the beauty of this place. Thank you.

  6. Fog is pretty, but as this goes on it’s smelling more and more like smoke. Please don’t use your wood stoves right now unless you need to.

  7. The aesthetics of fog elude me. Always seems to accompany dry winter weather which frankly can depress me if I am not careful. Now I am seeing another dry spell is predicted for Willamette Valley after a wet respite this weekend. Not good.

  8. Whatever happened to our "rainy weekend" coming up?


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