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Thread: Sunday looking like wave

  1. #1
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    Sunday looking like wave

    The low off the coast looks to setup a west wave condition for Sunday, the moisture and wind direction/profile are proper, the only catch is the depth of the boundary layer. After the strong heating of Wed-Fri, it may be too deep for wave. The RASP will tell…..
    Kemp
    ASH-25 (FNX)

  2. #2
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    Re: Sunday looking like wave

    Kempton, are you still expecting good wave on Sunday?

    Ramy

  3. #3
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    Re: Sunday looking like wave

    Thanks for the reminder. wave appears to be high, the 18K rasp shows wave, but not at 11K, so you can't get there from here.

    I'm flying at Minden with Tom for the Sierra wave.
    Kemp
    ASH-25 (FNX)

  4. #4
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    Re: Sunday looking like wave

    Quote Originally Posted by RamyYanetz View Post
    Kempton, are you still expecting good wave on Sunday?

    Ramy
    Update on Saturday 10 AM - regards to wave tomorrow.

    Take a look at these three current charts all for 3 PM tomorrow (that's PDT, which = 1400 PST):


    • Vertical Velocity at 10,000
    • V V at 18,000 and
    • the slice along that dotted line - that runs between Goat (point #2) and Black Butte (#3)

    Click image for larger version. 

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    Lift from Tree Farm to between Snow-St John-Alder 25 cm/s = 50 FPM at 700 mb (10,000 ft), but stronger (over 200 FPM) up to about 6 to 7,000 ft (too low) and you could work it up to over 11,000 and then head east past I-5 between Willows-Maxwell. You'd be below 9,000 before you found the mild lift (not enough) over the Sacto River, but if you got into it you could move forward (west) and get stronger, with about 200 FPM stuff at 18,000.

    That's all in theory, based upon these three charts.....
    Last edited by Peter Kelly; 05-03-2014 at 11:08 AM.
    Peter Kelly

  5. #5
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    Re: Sunday looking like wave

    Alternatively, using the same forecast charts as the basis, tow to 7,0000 ft, nearly straight to the north (maybe NNE), but you would be blown into the secondary wave as you drifted a bit east of straight north, and with the same result (in the wave at 7,000 ft), and it would be a much safer endeavor.

    If you did contact the secondary wave, you would need to move forward into the 30 kt (avg) wind as you climbed.
    You can see it clearly on the 700 vs the 500 mb charts that the lift moves about 5 miles upwind from 10,000 to 18,000 ft.
    Very Graphic example of the lift leaning into the wind as it ascends.

    It's a shame we can't draw out own line on that chart to see the vertical profile, or vertical slice, in the location where we would really be able to use.

    I remember Bob Ireland working with Dr Jack to bring that dotted line more into our flying area - some ten years ago.
    Last edited by Peter Kelly; 05-03-2014 at 10:34 PM.
    Peter Kelly

  6. #6
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    Re: Sunday looking like wave

    Update at 10 PM Saturday
    I just got around to looking at the RASP!
    Waaay different now.
    Sunday NO LONGER looks like wave.
    It looks like a valley thermal day.

    Noelle, I'll take a tow in ASW24-OJ at 11 AM if I may, thanks.
    Love the look of the WSC sounding.

    cu at 5,500 to 6,000 ft, wind less than 10 kts. no heavy cirrus. wowee.

    Click image for larger version. 

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    Peter Kelly

  7. #7
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    Re: Sunday looking like wave

    I could have posted an update here on this thread on Sunday AM since it negated the previous update - made on Saturday, but I chose not to take the time to post before I left home on Sunday. I did go to WSC and this the post flight.

    Ginny and Cindy said that yesterday (Saturday) had been an excellent thermal day in the valley. We all missed that one!

    As I mentioned on Saturday at 10 PM, high clouds had not been on the soundings the night before, but they were on the updated soundings on Sunday morning before I went to WSC. A few bands of decreased hi cirrus came through, but the prevailing cloudy sky was not unexpected. It was mostly a day with lots of grey sky from the high cirrus. I launched about 12:20 to 3,500 ft to the SW. The stratocumulus clouds, based at 5,500 ft, with tops mostly at 6,000) were in the areas of Capay Valley (isolated clouds there) with less than scattered clouds from Gold mines to Napa Valley and Bessa to Goat (by definition (METAR Codes) Scattered is 3/8 to 4/8ths coverage of the sky), so we had between "few and scattered" for the flying area I was in. Lines of cloud (and lift) formed clumps over the top of the up slopes like Gold Mines, Cobb Mtn, etc.

    When queried by Cindy-CP, 10 minutes after release from tow, my report was... "it's hard to lose altitude" ( meaning, if you stay under the clouds, then you are in lift). I cruised from Capay Vly to Cobb (NW of Crazy Creek) at 5,000 ft, toured the Geysers, but was on the down slopes, so I lost altitude and had to move east to a few miles N of Crazy Crk to get under the clouds again. Back up to 5,000 and headed towards Walker.

    That's when I should have used good judgment and reevaluated the day.... high cirrus becoming thicker, now past 2 PM - the high heat of the day, my support clouds becoming more isolated, wind picking up, attempting to fly through the cold air coming off of Clear Lake, not flying along up sloping ground....but... I could see a nice line of cloud leading me to Walker... but no airports within range, I should have turned back, right then and there, while I was still at 5,000 ft. Matt Herron and Son were over the gold mines and heading south, so it was still good over there. Losing 500 ft told me I was in the wrong place, but it was all too late. The clouds seem to evaporate instantly, I tried to work my way back up to the gold mines but to no avail. I couldn't get out of the stream of cold stable air coming out of the west from Clear Lake. A rookie move. I could hear Ramy's advice - fly the conditions, not the forecast. Even before the fight, I had repeated to the crowd of pilots at the picnic table what Rex had told me... "remember Peter, you don't have motor in this one", as I took my first flight in OJ a few months ago. Funny about all the thoughts you get during a crisis.

    I worked the lift lower and lower, attempting to drift uphill, in the direction of the gold mines, picking out landing spots as I circled.
    Attention was given to judging absolute altitude (altitude above the possible landing areas). In some of my early glider books it talked about seeing the legs of the cows, others talked about seeing the wheels on the cars and trucks - all good measurements - telling you that you are below 1,000 ft AGL. I knew I was below 1,000 ft so I put the gear down and flew a downwind base leg and landed without incident in a nice field. Hard packed, smooth with grass on the sides. I lucked out again - in more ways than one. Fly gliders meet new people. Really friendly land owner was not at all irritated, met the neighbors as well. I had called Matt Herron Jr - 22T- before landing and told him I was landing off field and he graciously relayed that info to Cora at Williams. I always want some to know when I am leaving the sky - recent thoughts of Malaysian Air. Keeping others informed is important, if not just plain considerate. Who knows what will happen when landing off field, even in a populated area.

    Within seconds after getting out of the ship, I phoned Cora at Williams and reported all was OK.
    She had my location on the SPOT trace.
    Click image for larger version. 

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    I spent time talking to the owners and neighbors, and coordinating with Cora over the phone.
    This is the view of the field looking NW, in the direction of landing. The field was flat and I had pulled the glider back up towards the road.
    Click image for larger version. 

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    It's good to have friends, and as the expression goes, it is really good to have friends in high places. Noelle was my enthusiastic guardian angle. After getting the trailer lights back into working order, she was on the road before 4 PM to come and rescue me.

    Click image for larger version. 

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    We were back home again at WSC a few minutes past 6 PM. Another very efficient retrieve.
    As you can see from the graphic, I was at Lower Lake, just off of Highway 29. I can assure you I did not select the field based on convenience, but it sure worked out OK. I was just plain lucky - and I am indebted to Noelle. I think I can best repay the debt by demonstrating a bit more judgment on future flights - especially in her gliders.
    Peter Kelly

  8. #8
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    Re: Sunday looking like wave

    Quote Originally Posted by Peter Kelly View Post
    Alternatively, using the same forecast charts as the basis, tow to 7,0000 ft, nearly straight to the north (maybe NNE), but you would be blown into the secondary wave as you drifted a bit east of straight north, and with the same result (in the wave at 7,000 ft), and it would be a much safer endeavor.

    If you did contact the secondary wave, you would need to move forward into the 30 kt (avg) wind as you climbed.
    You can see it clearly on the 700 vs the 500 mb charts that the lift moves about 5 miles upwind from 10,000 to 18,000 ft.
    Very Graphic example of the lift leaning into the wind as it ascends.

    It's a shame we can't draw out own line on that chart to see the vertical profile, or vertical slice, in the location where we would really be able to use.

    I remember Bob Ireland working with Dr Jack to bring that dotted line more into our flying area - some ten years ago.
    The dotted line (for the cross section) can be plotted for any coordinates. This is what we did for Hollister/Byron RASP. Andy should be able to set it up easily for multiple cross sections.

    Ramy

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