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Thread: Unstable Air - 9/29/2019

  1. #1
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    Unstable Air - 9/29/2019

    This weekend is one for the record books for glider pilots at Williams.
    There are other threads about pilots planning to fly as they look ahead at the weather soaring forecast (fcst).
    See... First post was by Luke, posted on the Monday prior - and he calls it "interesting"...
    Other pilots do start to chime in, and talk a bit about it by Wednesday...
    https://www.williamssoaring.com/news...mber-28-and-29

    Several pilots had very long flights, see reports on other postings....

    The purpose of this post is to display the instability (via the simple sounding charts shown on the RASP) and show a couple of screen captures of photos that were easily found by putting "tornado davis california" into a google search.

    First, the soundings from yesterday *Saturday, 9/28. The ones for today, Sunday 9/29 will be shown on a lower addition to this thread.

    From yesterday, Saturday, 9/28...
    These are for Williams at 2 PM, 5 PM and 6 PM...

    Click image for larger version. 

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ID:	5424Slope of the red line bottom to top... same slope as the lapse rate lines in the background. one for 1400 hours... surface to 10,000 ft - any air that is warmed will continue to rise

    Click image for larger version. 

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    By 5 PM instability increases up to about 17,000 ft, and then at 6 pm it increases even further... see image below...

    Click image for larger version. 

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    Sounding for the tower east of the north end of lake Bessa...

    The first one is for 1 PM and the second one is for 5 PM...
    Click image for larger version. 

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    A little closer to the gliderport at 1 PM is the three sisters sounding - at 4 PM...

    Click image for larger version. 

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    Unlike the others, this shows the blue line touching the red, and the accompanying black line on the left margin, indicating clouds sitting over the hwy 20 gap/ 3 sisters TP, bases at about 9,000 ft with the tops about 12,000 ft.
    Last edited by Peter Kelly; 09-29-2019 at 11:59 AM.
    Peter Kelly

  2. #2
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    Re: Unstable Air - 9/29/2019

    Spectacular photos from yesterday's "weather".... not called a Tornado (doesn't meet the standards) but since nearly everyone carries a cell phone and readily snaps photos, here are a few of the many images that were posted on line...

    All of these were snapped in and around Davis CA about between about 5:30 and 6 PM -ish.

    Click image for larger version. 

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    And the most spectacular was a video captured - this may be from the video captured by B. Prill @WxBrenn?
    see.. https://twitter.com/WxBrenn?ref_src=...Ctwgr%5Eauthor

    Google it, and you will probably find it. Note the bales of hay in the air well above the new orchard. This may have been just north of Davis along Pole Line Rd/ Road 102?

    Click image for larger version. 

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    end
    Last edited by Peter Kelly; 09-29-2019 at 11:36 AM.
    Peter Kelly

  3. #3
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    Re: Unstable Air - 9/29/2019

    I keep watching the schedule - but no rentals available again today either. So I'll be sitting this one out as well. Lots of activity on the flight line at 11 AM

    Click image for larger version. 

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    I posted sounding from yesterday is the first section of this thread, but you should realize that today's soundings are nearly as equally as unstable.

    Here are a few soundings from today's RASP... nearly the same instability, but b/s ratio will be more favorable since wind is greatly reduced...

    for 2 PM today at Williams
    Click image for larger version. 

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    and for Bessa Towers today at 4 pm...
    Click image for larger version. 

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ID:	5429 and we can expect to see some nice cu over 3 Sisters beginning after noon ...

    and looking good at 4 PM... Click image for larger version. 

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ID:	5429 note the black line on left margin again.
    Last edited by Peter Kelly; 09-29-2019 at 12:12 PM.
    Peter Kelly

  4. #4
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    Re: Unstable Air - 9/29/2019

    BS Ratios Saturday vs Sunday...

    Attachment 5430 Attachment 5431
    Peter Kelly

  5. #5
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    Re: Unstable Air - 9/29/2019

    Very Unstable. I saw some debris going up in a thermal today somewhat similar to the debris in the tornado video. I wonder if it was the same stuff??? We were able to cross the delta two days in a row. I didn't take any photos flying but took one at sunset last night from Williams.Click image for larger version. 

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