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Thread: Wed/Thu Feb 12-13 wave

  1. #1
    Join Date
    Jan 2011
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    Menlo Park, CA
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    933

    Wed/Thu Feb 12-13 wave

    There's wave, then there's waviness. I've noticed that waviness in the 700mb chart tends to correlate with better soaring wave days. Such as we have at hand now. Note the isobar waviness in the current 700mb for Wed Feb 12:
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    and the RASP for the same:
    Click image for larger version. 

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    plus note there's tighter 850mb isobars (ridge line level) than for Thursday (further down this post):
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    but for Thu Feb 13 the waviness is gone:
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    and the RASP looks poor:
    Click image for larger version. 

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    plus the 850mb flow is poor judging by the widespread isobars:
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    I've noticed this for the Sierra but hadn't had the tools to correlate long range forecast chart features to near-term actuals, either for the Sierra or WSC.

    So Pat Alford, Wed looks good. Jim D and I were thinking about Thu, but this now calls that off. BTW, the cause of the poorer performance on Thu is due to the introduction of unstable air that makes for less transmission of lower level "bounciness" to upper level air.
    Last edited by Kempton; 02-11-2014 at 01:10 PM.
    Kemp
    ASH-25 (FNX)

  2. #2
    Join Date
    Sep 2013
    Location
    Fremont, CA
    Posts
    219

    Re: Wed/Thu Feb 12-13 wave

    Kempton,

    This is fascinating! This kind of insight can only come from years of reading and studying weather charts. I appreciate you sharing your observations and knowledge with us!

    Pat
    Last edited by Pat Alford; 02-11-2014 at 01:08 PM.

  3. #3
    Join Date
    Sep 2013
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    Fremont, CA
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    219

    Re: Wed/Thu Feb 12-13 wave

    I ended up enjoying a very nice wave flight yesterday, February 12, courtesy of the Pineapple Express!

    I got off tow in the well-marked secondary at 7,000' near the eastern edge of Bear Valley. I climbed in a steady 3 knots of lift to 14,500' and then made my push into the primary. I arrived and connected with the primary at ~10,000'.

    This is looking west on my first northbound leg near Black Butte.
    Click image for larger version. 

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    I ran as far north as Anthony Peak. This is looking back down the Foehn Gap Highway shortly after turning.
    Click image for larger version. 

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    I stayed on the Foehn Gap Highway as far south as it went, which was abeam High Valley, and then ran north again. This is looking up the gap just after passing Diamond M. The Alder Springs complex can be seen in the center of the gap below the little wispy cloud.
    Click image for larger version. 

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    ClearNav shot taken 13 minutes later. The progression was so slow in this area because of the 50 knot headwind in the direction of travel.
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    An interesting eye of the hurricane effect on this cloud just south of Black Butte.
    Click image for larger version. 

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    I stopped 4 miles short of Anthony Peak on this leg and turned thinking I would still have time for a southbound leg to Lake Berryessa. Again looking down the southbound highway.
    Click image for larger version. 

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    This is looking west near Alder Springs.
    Click image for larger version. 

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    By the time I got back down to Bear Valley I realized I wasn't going to have time to run farther south, so I headed back to Williams. I pulled full dive brakes six miles out at about 10,500', and at three miles out I practiced a benign spiral to get down to pattern altitude. I was surprised at how stable OJ was in the spiral.
    Click image for larger version. 

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    Official sunset was at 17:42. I landed and had wheels stopped at 17:41:51. I did not intend to cut it that close! Another lesson learned.

    All in all it was a fantastic flight for me and I had great fun! 4.3 hours and OLC scored it at 392.5km. OLC posting is here:
    http://www.onlinecontest.org/olc-2.0...l?dsId=3473272

    Pat
    Last edited by Pat Alford; 02-14-2014 at 07:04 PM. Reason: Punctuation fix.

  4. #4
    Join Date
    Jan 2011
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    Schleicher ASW-24
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    2,103

    Re: Wed/Thu Feb 12-13 wave

    Pat,

    I'll add to Larry's comment.
    Congrats on a nice job of predicting, and flying the wave. You logged a good number of OLC miles.
    Really nice photos as well.
    Good job.
    Peter Kelly

  5. #5
    Join Date
    Sep 2013
    Location
    Fremont, CA
    Posts
    219

    Re: Wed/Thu Feb 12-13 wave

    Peter,

    Thanks for the kind words! Regarding the predicting part of wave flying, everything I know about that I've learned from you and Kempton. So, thank you both for sharing your knowledge!

    Pat

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