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Thread: Wave Alert: Monday Dec 30

  1. #1
    Join Date
    Jan 2011
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    Menlo Park, CA
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    966

    Wave Alert: Monday Dec 30

    A cutoff low looks to come in Monday, 6 days out, setting up an offshore flow wave day. As we've observed, cutoff lows wander more so than "big" systems, as they're "small" weather systems, so forecasts are less reliable until 2-3 days out. We post anyway because if/when they do setup, the day can be spectacular. This is 6 days out, with flows from 030 to 060:
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    and the winds at 18,000 are quite civilized, 40-60kts or so:
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    The forecast above looks to light up the entire Mendocinos, from Napa to Hoopa. If this holds, then the task is a zig-zag btwn Hoopa and Napa. Comparing this to other NE wind days, this is the closest to the Nov 22, 2013 flight with Pat Alford in the Duo:
    https://www.williamssoaring.com/news...89-Friday-Wave

    Similar setup, wind direction and strength, but shorter days 8^(. Otoh, we know alot more about the wave hot spots, so can consider a 1000K zig-zag.

    For those not experienced with NE wave soaring, it's highly likely the Sutter Buttes will work, plus the Buttes are upwind. The key risks in the Mendos NE wave are heading directly into the wind to return to WSC, and if you miss the wave, you're blown downwind. You pretty much need a modern 18m ship or better.

    WSC confirmed they plan to be open, so long as the wind doesn't preclude opening hangar doors, which it doesn't appear will be an issue at this point.

    Will post more on this as we get closer.
    Last edited by Kempton; 12-26-2019 at 11:51 AM.
    Kemp
    ASH-25 (FNX)

  2. #2
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    Re: Wave Alert: Monday Dec 30

    For comparison these are the 72 hour in advance GFS charts of Nov 22, 2013:
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    https://www.williamssoaring.com/news...-%28Thu-Fri%29
    Kemp
    ASH-25 (FNX)

  3. #3
    Join Date
    Aug 2014
    Location
    Menlo Park CA
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    Re: Wave Alert: Monday Dec 30

    Wow! That's also a more easterly component than I've ever seen -- straight across the mountains.
    John Cochrane BB.

  4. #4
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    Re: Wave Alert: Monday Dec 30

    Following closely and considering flying.

    Ramy

  5. #5
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    Re: Wave Alert: Monday Dec 30

    Update Thu Dec 26, 4 days out. Stable forecast, meaning it's not changing much. It still might, so not committing until Sat morning:
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    Skysight
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    Forecast ground winds <15kts @8a? For now... Burned by the last time where 50mph winds hit, I have the least confidence in this, so will watch.
    Click image for larger version. 

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ID:	5503 Skysight 2m winds @8a

    The likelyhood of excess surface winds is less as the 500mb winds aloft are 45kts vs. 80kts last time.

    Sunrise 7:28a, Sunset 4:55p, 9.5 hrs of daylight.
    Looking good so far.
    Kemp
    ASH-25 (FNX)

  6. #6
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    Re: Wave Alert: Monday Dec 30

    TG is planning on a sunrise tow as well if possible.

    Ramy

  7. #7
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    Re: Wave Alert: Monday Dec 30

    To share what I'm thinking, here's the task:
    Click image for larger version. 

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    Launch 7:28a, 8a release
    140sm Goat S start to Hoopa Air 10:30a (30m to climb to 18K, 2 hr on course)
    182sm Hoopa Air to Angwin Air 12:30p
    182sm Angwin Air to Hoopa Air 3:00p
    153sm Hoopa Air to WSC 4:45p, sunset 4:55p
    657sm Total

    Because this is an OLC flight, the turnpoints are approximate to estimate distance, actual turns will be near and beyond each preferably.
    Kemp
    ASH-25 (FNX)

  8. #8
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    Re: Wave Alert: Monday Dec 30

    Kempton, Ramy,

    Keep us posted on your plans. It's exciting to watch you plan and accomplish such flights.
    We'll be watching while you're inflight
    Peter Kelly

  9. #9
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    Re: Wave Alert: Monday Dec 30

    Sunday morning, Ramy and I are here, he assembling in the rain:
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    and me dealing with a bad lift strut:
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    The forecast has degraded a bit, with a more N flow, but the flip side the wind speed is less, like 35-45kt strengthening during the day. I wouldn't want it any slower:
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    and later in the day
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    Right now, the squad to launch is:
    - Thomas in the '22
    - Ramy in his '29
    - John Cochrane in his '31
    - Me in the '25
    and possibly Dave Greenhill in his D2.
    Kemp
    ASH-25 (FNX)

  10. #10
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    Re: Wave Alert: Monday Dec 30

    In the end, it was a pretty good flight, if only because our expectations were beaten down so severely. A 5 hour flight for Alex and me btwn Hull and Kenwood, max altitude of 16.5k. Ramy was 4 hours btwn Goat and St Helena. Longest in the USA 8^p
    https://www.onlinecontest.org/olc-3....l?dsId=7668720

    The morning was spent enjoying the geese flyover:
    https://drive.google.com/file/d/1JRj...ew?usp=sharing

    re-reviewing RASP, finding real-time wind stations:
    https://www.wrh.noaa.gov/map/?obs=tr...obs_popup=true

    as the cutoff low moving further away:
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    >> Andy, can we access archive RASP? I'd like the Dec 30 850, 700 and 500 10a charts for reference, I didn't save them....

    The RASP showed nothing at Goat until 2p, but with sunset at 4:55p, and a sunk cost of being at WSC going thru a rainy assembly, and no wave flight this season, I was motivated to fly wave. By 11:15a, I had had enough, and felt that there should be SOMETHING esp. given my experience that RASP tends to undercall wave. Reviewing our Plan A & B, that is, tow to Goat, if no wave, then continue tow to Snow higher to try that and buy some time for the Goat wave to setup. RASP had showed the wave setups starting in the north, and propagating south. Rolling at 11:55a, with Alex in front. Ramy preferred to wait until we confirm the wave, then he'd tow.

    While on tow, we see rotor cu on the backside of St. John, the burn area south of Black Butte, Snow and Goat, so we are very encouraged.
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ID:	5513 center, right above ridge. Likely the rotors were showing up due to the higher than normal RH, about 60%.
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ID:	5514plus the usual valley fog seen on N wind wave days

    We directed Ben (towing) to halfway btwn the Goat ridgeline and the valley floor as with the light winds the wave length will be shorter. Off tow in the Goat wave, we have 2-3 kts but variable up to 14k. More important, winds are light, 12kts at 9k, slowly increasing to 28kt at 14k. Later in the day, we see 36kts, so covering ground is easier, but the climb rates are less. We expected variable lift rates as the RASP forecast wave structure had gone from a nice straightup lift band, to a "S" shape leaning into the wind, so it's easy to miss the core lift area as it wanders with altitude. Short video during this climb to 14.2k:
    https://drive.google.com/file/d/1ovV...ew?usp=sharing

    Having see a rotor wisp at Hull we headed there via Snow (1-2 kts) got to Hull at 11.5k only to find <1kt lift, so we headed back to Goat to join Ramy. Ramy, now higher than us, heads out to St. Helena where we see rotor wisps downwind in the Santa Rosa area. He finds a small lift area, so we join him. After topping out we go down the Napa valley wave for a ways, then lose the lift as the ridgeline drops. Alex & I sample the Kenwood wave, find nothing, and rejoin Ramy at St Helena for the last climb to 14k. It's now past 4p, so time to head back. Ramy tags the Buttes wave of 0.5kts at 4k 25 minutes before sunset.

    Click image for larger version. 

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ID:	5515Landing was uneventful, right at sunset.
    A very interesting day, if for nothing else to see how little wind we need for wave. Part of what made the wave work better than forecast imho, is the stability of the air due to the cold of winter.

    Thanks again to Ben for towing and providing encouragement, Nick for fixing our trailer, Noelle and Rex for support, Ramy for believing when there wasn't much to believe in, and Alex for sticking with the whole thing.
    Kemp
    ASH-25 (FNX)

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