December 31, 2010

Upcoming Drought



You may not believe it, but we are now starting a mini-drought here in Seattle. After a wetter than normal year, there is now no precipitation in sight until the middle of next week. And even better than that, there will also be considerable sunshine each day, which really helps lessen the midwinter blues.

This is all caused by a strong ridge of high pressure over us (see image) and an associated split in the jet stream with

disturbances and rain hitting central and southern CA (see the precipitation forecast over the next 72 h shown below).

Those poor devils in southern CA are getting hit hard, with many locations in southern CA "enjoying" their wettest or second wettest December on record. Downtown Los Angeles has received 10.23 inches this month, 8.4 inches above normal. Snowpack in the Sierras is over 200% of normal....well they wanted more precipitation!

Returning to our situation, Seattle has had 46.99 inches this year, 10.09 inches above normal. Last year Seattle had 38.17 inches...pretty close to normal. Olympia has had 55.44 inches this year, ONLY 4.89 inches above normal (yes, Olympia is much wetter than Seattle, because Seattle is rain shadowed by the Olympics). And Spokane has had 19.03 inches, 2.36 inches above normal. So this has been a relatively wet year over the state. Cascade snowpack is near normal at this point.

Finally, there is one negative with a ridge of high pressure above us this time of year--cold temperatures at the surface with lots of frost. Clear skies allows the earth to radiate energy to space through the long winter night, resulting in cooling at the surface and the development of nocturnal inversions (temperature increasing with height). The roofs are white outside my window right now. And one can also get freezing fog, so be carefully while driving if you see any fog around.


  1. Man, did I pick the wrong year to move from Seattle to San Diego. The weather feels just like home down here :)

  2. Great day for photography! Stunning views of the mountains. A bit of alpenglow action going on. I'm loving these bright winter days, as the days get longer too. Off to take pictures....Happy New Year everyone! Thanks Cliff for all you do.

  3. 11.14 inches in Yakima. Around 8 is the average. First double digit rain since 96. Every year prior was mostly below average, 14 years! Perhaps a local effect of climate change.

  4. Another oddity of this winter:At Sea-Tac, this December will end up as the warmest since 1991,and second warmest since 1980.

  5. To what extent, if any, do you attribute the above average rains here and, particularly, in California to La Nina?

    And, if we aren't expecting any rain until next Wednesday, is the Climate Prediction Center off the mark in predicting above average precipitation in the 6-10 day outlook, or should we expect some heavy rain coming to balance out these dry days?

  6. Great pic of Seattle. Speaking of pics, on the news people are getting all excited over double rainbows. We see many many double rainbows from Capitol Hill. So, why the excitement?

    Are double rainbows rare in other parts of the country?

  7. In some cases, for those with summer SAD (so called because of the higher prevalence of sun in the summer, but it can occur anytime there is sun), this weather causes midwinter blues in people that usually feel great this time of year. Especially when there is sun for a week at a time such as now. At least we only have to stay indoors until a little after 4pm, contrary to near 10pm as in the summer.

  8. We gardeners are also keen weather observers and photographers. Sunny winter days bring out the yellows, oranges, reds, and blues in ornamental heathers and conifers. They also highlight the brilliant bark of trees like the coral-bark maple and the white paper-bark birch.

    The downside, however, is the manner in which those bright cold days were delivered to us this fall and winter. I live in Olympia, where the FIRST frost was late in the year (afternoon of 11/22), precipitous (slid to 19F by the next morning) and long-lasting (over 60 hours below freezing). In other words, the earlier mild frosts plants use to speed up their hardening-off processes were largely missing.

    Last night (12/30) was the first time it dropped below 30F since over a month ago; and again it slid to below 20F by morning. Tonight it may get even colder. Any plants that were fooled by the preceding month of relative mild weather following the first deep freeze are getting slammed again with a second!

    It's not just plants that are taking a beating, either: The ranks of those Adventurous Gardeners who practice "zonal denial" will dwindle once again, as they have after the last two winters. That includes me . . . !

  9. So, take advantage of free solar energy. Open your shades on the SOUTH-facing windows during the daylight hours. When we get these clear, cold days we can enjoy the same solar benefits as New Mexico and Colorado. No sense paying the utility companies more if we can help it!

  10. 2nd warmest winter since 1991? How come with steady temperatures of 25-30F for days it just doesn't feel like that?

  11. Hey Cliff:

    Happy New Year!

    What about the impact of the record snow in Siberia?

    Is this global warming or global cooling?


  12. Just moved to Seattle form Montana and am really enjoying your blog, which one of my really nice neighbors was kind enough to share. Coming from a state which is overrun with cheatgrass, knapweed and square miles of beetle killed pine, I am pretty amused by the definition here of a mini - drought - a few days without rain! Saw more rain here in one hour than it took several months to get in MT.

  13. Hey Cliff,

    You're the man. The only thing i've ever emailed anyone a link for is your blog.

    That olympia/Seattle annual rainfall total disparity was interesting.
    Where can we find annual totals for other WA locales?


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