August 01, 2008

incoming fog -- it's Sky Watch Friday !


click photo for full-size image
photo by Donald Kinney

Hope everybody is having a great Sky Watch Friday!

Yes folks, this is our fog -- our natural air-conditioning -- marching in towards the Golden Gate.   The photos you see here were taken from Ridgecrest Boulevard, the northern flank of our beloved centerpiece of Marin County, Mount Tamalpais.

I stopped by Wikipedia to get the official "low-down" on fog -- and thre it was, a picture of San Francisco, pretty much cloaked in the wonderfully cool stuff:

photo lifted (without direct permission) from Wikipedia.org

[[[ quote ]]]
Fog forms when the difference between temperature and dewpoint is (5 °F) 3 °C, or less.
Fog begins to form when water vapor (a colorless gas) condenses into tiny liquid water droplets in the air.   Conversely, water vapor is formed by the evaporation of liquid water or by the sublimation of ice.   Since water vapor is colorless, it is actually the small liquid water droplets that are condensed from it that make water suspended in the atmosphere visible in the form of fog or any other type of cloud.

Fog normally occurs at a relative humidity near 100%.   This can be achieved by either adding moisture to the air or dropping the ambient air temperature.   Fog can form at lower humidities, and fog can sometimes not form with relative humidity at 100%.   A reading of 100% relative humidity means that the air can hold no additional moisture and the air will then become supersaturated if additional moisture is added.

Fog formation does require all of the elements that normal cloud formation requires with the most important being condensation nuclei.   When the air is saturated, additional moisture tends to condense rather than staying in the air as vapor.   Condensation nuclei must be present in the form of dust, aeresols, pollutants, etc. for the water to condense upon.   When there are exceptional amounts of condensation nuclei present, especially hydroscopic (water seeking such as salt, see below) then the water vapor may condense below 100% relative humidity.

[[[ end quote ]]]


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46 comments:

KylieM said...

ooo look at that fog, must try and get some fog photos here in Canberra, its a common occurance. Cool Skywatch

kjpweb said...

Brilliant colors on your fogwatch today! ;)
Very enticing!
Cheers, Klaus

Anne-Berit said...

Wonderful Sky Watch-post!

Anonymous said...

Excellent again.. and I am probably repeating myself. Again.
If I sound bored - am certainly not.

chanpheng said...

That's a great fog picture. I remember how cold SF could be when the fog rolls in - even during the summer.

Thanks for stopping by my blog. The camera is still working, I hope for many more SWF pictures.

Country Girl said...

Hi. I know I've been here before because the photographs are awesome. I hope I left a comment last time. I absolutely love this photograph, the top one especially. I love the color of the grasses combined with that awesome sky!
BTW, I find it amusing that our blogs are almost the same name. I really hadn't seen you before and was not trying to copy! Thanks so much for stopping by my place.

Gattina said...

I really love the first picture it reminds me my childhood holidays with my grandparents.
BTW I also have a cat blog where you can see my little Rosie and her siblings. http://gattinamycats.blogspot.com/.
Now I am off to see yours !

Indrani said...

Not just good shots, very informative post too.

Lynellen said...

Very cool photo. Thanks for sharing with SkyWatch!

Have a great weekend!

--Lynellen, #262 on this week's SkyWatch
Shop online with me your Mary Kay Beauty Consultant

Kahshe Cottager said...

Excellent Sky Watch post! Loved the photo and learning something new about fog!

Thanks for your visit to my SkyWatch!

Snap Catch said...

Lovely view! Great catch for skywatch! Happy weekend! Hope you'll visit mine too...

dlyn said...

Such a gorgeous place! I love fog and all the varying images we can get from it. Happy Skywatch Friday!

Pat - Arkansas said...

Superb photograph! I've not been to the San Francisco area, and really had no idea that the surrounding countryside was so beautiful. Thanks for sharing these glimpses. Lovely Sky Watch.

I'm greatly enjoying your blog; your photographs are inspirational.

rachel said...

what a fantastic view!!! very wonderful!

magiceye said...

looks heavenly!
thank you for your visit and comment on my blog.

me ann my camera said...

Very, very beautiful grasses in the foreground of your skywatch!

pts said...

excellent post!

Mary said...

Oh so lovely with the grasses swaying in the foreground! We have horrible humidity here in NJ but nothing as beautiful as that! :( Happy Skywatch Friday!

Louis la Vache said...

Beautiful images, Donald!

"Louis" hasn't had much time for commenting recently as he's very busy in a work project, so here's some belated replies to some of your visits.

"Louis" ran into a situation like you described about being prohibited from photographing the ships when he took the "Here today, gone to Maui" image. He was somewhat forcibly told to move from one vantage point. We can thank 9/11 for this...

Re ABC Wednesday - Despite "Louis's" repeated efforts to get on board the new format, Mrs. Nesbitt hasn't sent "Louis" instructions on how to post on the new site. So "Louis" has been going it alone because he likes the meme.

Brad Myers said...

Nice skywatch photo, I really like the cat tails photo also.

Texas Travelers said...

Great photo and I like the grasses. Your comment about the Red Newt came in while I was writing this. Godd luck to both of us.

Troy

Bummer about the Epson.

Kim said...

Great information. I love the sun hitting the weeds and the clouds, very cool composition. I also love your title image.

Carver said...

Those are wonderful shots. I love fog as long as I don't have to drive in it. The tall grasses are so beautiful to me.

Dancin Fool said...

Hello! Wow, your picture is amazing! I have never seen anything like that before.

I read your profile and wanted to ask how I can get into your industry? Your profession sounds perfect for me!

Have a brilliant weekend!

Anonymous said...

This is a fantastic photo. I love the way you captured the grasses with the fog moving in on them. Excellent.

Thanks for visiting I Was Born2Cree8. I appreciated your comment.

Alice at: I Was Born2Cree8
My 1st SWF post is here: Sky Watch Friday

Reba’s dog blog: Reba’s Run
Reba’s 1st SWF post here: Sky Watch Friday

Anonymous said...

So beautiful !! And the photos on your big site : magnificent !!
P.S. the eclipse and the tower are taken at the same spot, but the first one is with eclipse glasses and the second one with sun glasses before the camera lens.

DigitalShutterMania said...

Wow wonderful sky watch photo.

Sparkle Plenty said...

The picture at the top of the page makes my brain relax. Thank you, Donald! I needed that! :-) Hope you and kitty have a great weekend.

SandyCarlson said...

Thanks for these beautiful shots.

marley said...

Great photos. It may sound weird but I like fog! It makes everything mysterious.

Anonymous said...

Great photo! I love looking at the fog and find it fascinating but I can't stand being in it when it's so thick you can hardly see.

Babs (Beetle) said...

Lovely photo. I saw that rolling towards me once - it looked quite eerie.

Anonymous said...

Fog that thick brings horror movies to mind.

Kim said...

Great photos...someday I'll go out west and see it for myself! Looks awesome!

Tink *~*~* said...

Fog is clouds that decided to hug the ground! :D

LOVE your Donald Duck avatar :D

Tink *~*~*
My Mobile Adventures *~*~*

Jeanne said...

Wow another great capture of moisure formations in your beautiful area. Love the vegetation in the foreground.

Roan said...

Love the fog. Magnificent! Hope you're having a great Skywatch Friday. Happy weekend!

Tomate Farcie said...

Wow, there is a whole party going on in here today! Cool! :)
Great shot! I'm a little late today for my visit (it was a very long day). Nice to be back to looking at soothing photographs, and thank you again for posting.

Torsdag 1952 said...

Hallo,
very nice SWF, I like the contrast light blue sky, white and dark clouds. The foreground is not dominating.
Hallo from Germany

Fish Whisperer said...

As usual you photos are superb. Have a great weekend.
Cheers

Indigo-Daisy said...

Was in SF last year for my sons graduation in June and nearly froze to death. Didn't see any fog though. What an awesome picture!

Louise said...

Your fog photo is better. Thanks for the education excert. I didn't know about the temperature span that created fog.

Markus Latva-aho said...

Hi! Very nice photo for sky watch! I liked your cat tails pic!

esnorway said...

great pics have nice weekend

Rebecca (Ramblings by Reba) said...

Beautiful!

Catherine said...

Beautifully colored fog! Great sky~watch capture! Also love the cattails in previous post! :)
Enjoy your week!
Cat

 
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