Category Archives: weather

Katabatic wind

Posted on December 5, 2016 by Alistair

  A recurring theme of mine over the years has been that of a katabatic wind: the gentle stream of air that flows down a mountainside overnight. Indeed, I wrote about it fifty years ago, again this year with 23 cm/s, and with … Continue reading →

Posted in weather | 4 Comments

Making waves

Posted on November 24, 2016 by Alistair

  It may seem odd that I consider the picture below to be special. As a shot of a muskrat swimming, it is distinctly ho-hum. But, as a shot characterizing water waves, it is long-sought superb. This demands an explanation.  Almost any … Continue reading →

Posted in mammals, weather | 2 Comments

No lollypop

Posted on November 5, 2016 by Alistair

  I tried, but I didn’t win the lollypop — but I did manage something almost as good. I rarely fly anymore, but when I do, I ask for a window seat away from the wing. There are things that … Continue reading →

Posted in scenes, weather | 2 Comments

23 cm/s

Posted on October 12, 2016 by Alistair

  Katabatic wind: a usually gentle wind of cool air that drains down the mountain slope overnight. When the sun warms the slope and the air above it, a katabatic wind usually stops. Yestermorn, I was watching the languid drift of steam … Continue reading →

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Fallstreaks

Posted on September 18, 2016 by Alistair

  When I was in elementary school, I was taught that when water has a temperature of less than 0 °C (well, 32 °F at that time), it is (invariably) a solid called ice. And I was told that it is a liquid … Continue reading →

Posted in commentary, weather | 2 Comments

Hotspot

Posted on August 29, 2016 by Alistair

  Now that the wildfire season seems behind us, no concern is likely to be raised by a discussion of something called the hotspot in the forest. The hotspot is an optical phenomenon in the form of a diffuse bright region around … Continue reading →

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Rainbow season

Posted on August 24, 2016 by Alistair

  One year differs from the next. Last year had a dramatic forest fire; this year almost nothing burned. Last year we hardly noticed black bears; this year they abound. Last year offered copious dragonflies; this year there were few. There are years … Continue reading →

Posted in weather | 1 Comment

Momentum transfer

Posted on July 28, 2016 by Alistair

  Wind has momentum: After all, it is a moving mass of air. The magnitude of this momentum usually varies with height in the atmosphere, because aloft the density is lower but the wind is typically stronger. Convection in the … Continue reading →

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Hailstorm

Posted on July 16, 2016 by Alistair

  The day bounces around from sun, to cloud, to rain, to hail, and back to sun. The sight and sound of hail falling on the Lake is magnificent. Depending upon the size of the hailstones, the sound ranges from … Continue reading →

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Sky line

Posted on May 1, 2016 by Alistair

  The title is not a typo: this is about a sky line, not a skyline. The last time I saw a nice example of this was three years ago: sky lines. This posting is an adaptation of what I … Continue reading →

Posted in weather | 3 Comments