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Thread: LongPac Tactics Seminar on May 12th

  1. #11
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    Default Tonight 7:30

    Tonight, don't miss this opportunity.

  2. #12
    pogen's Avatar
    pogen is offline Sailing canoe "Kūʻaupaʻa"
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    Default Stan's slides?

    Very interesting and informative talk last night, a big thank you to the SSS organizers and Stan for making this possible.

    Is there a chance of getting a copy of Stan's powerpoint slides? I took notes but I'm sure I missed some stuff, the detailed info was coming at us pretty fast.

    Thanks!

  3. #13
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    Default

    That was outstanding. I've heard the TransPac part twice before and have read Stan's article (on the PacCup website) several times, and each time I feel like I "get" more of it. Here's a link to the article:

    http://www.pacificcup.org/stan-honeys-weather-advice

    Correct me if you heard it differently - the three race stages in this article form the second, third and fifth of the five stages he discussed last night.

    The first stage, getting to the synoptic wind, is the most important for the LongPac. I realize now I was focusing on the wrong GRIB file models for this.

    Anyway, thanks a lot for setting that up AJ. It was great to have a full house for it, so also a 'thank you' to everyone for coming, and most of all to Stan and Sally.

  4. #14
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    Default

    Quote Originally Posted by pogen View Post
    Is there a chance of getting a copy of Stan's powerpoint slides?
    I asked Stan the same question last night, and he said yes. We'll get them up on the website soon.

    Max

  5. #15
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    Default

    Any news on posting of Stan's slides??

    I really liked his discussion of weather models and their use in generating GRIB files for near offshore conditions. What were the two weather models that he spoke of? I can't recall which one was preferred for generating GRIB files for the LongPac...can anyone help with a quick summary.
    Richard
    Libations Too

  6. #16
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    Default

    Rich, thanks for the reminder. I'll email Stan again.

  7. #17
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    Default

    Richard, the two models Stan discussed were COAMPS and GFS.

    The Navy's COAMPS model accounts for terrain effects and is good within 20 miles of shore. Stan recommended studying the COAMPS grib files to determine how best to reach the synoptic breeze.

    The GFS is more common and is recommended for offshore. GFS is what you get with PassageWeather, Grib.us, etc.

    I can request gribs from either model from SailDocs through my nav software, but as I studied up for LongPac I discovered the COAMPS gribs are only available a few hours ahead, and are not interpolated (the grib "barbs" are really spread out). For example, the COAMPS grib files I studied for Spinnaker Cup (SF to Monterey) gave me only three or four relevant reference points along the coast, and I could not get a forecast very far ahead.

    So as it turned out, the raw COAMPS data wasn't that useful for LongPac planning. Other local weather sites were more helpful since they interpolated the data for you and projected farther ahead - but that's mostly my lack of experience with this stuff.

  8. #18
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    Thanks Bob!

    What did you mean when you indicated that the COAMPS gribs were "only available a few hours ahead"?
    Richard
    Libations Too

  9. #19
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    I'll have to fire up the waffle iron* again and do some grib requests to answer precisely.

    My nav software formats the grib file requests (from SailDocs) according to the range of lat/lon and time periods I specify. My recollection is I could specify a time period for GFS grib files out to five days, but only one or two days for COAMPS gribs. In a way that makes sense since the COAMPS gribs are intended for use close to shore. I also recognize that forecasts beyond 2-3 days are not very reliable.

    Where it's a problem is if you wanted to do your forecasting on Tuesday night for the LongPac race running Wed-Sunday, and you won't have access to e-mail during the race. If you want grib files for the whole race (inaccurate as they may be) you have to request the GFS-based files.

    * Old SH TransPac reference. It had to do with getting gribs on your grids, maybe with a side of grits. Okay, you had to be there . . .

  10. #20
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    Default Coamps

    Bob, I think you're right about getting around 2 days of gribs with Coamps. But you can actually get better resolution than GFS. Coamps is available on a .2x.2 deg grid, while the smallest available for GFS is .5x.5 deg. Between here and Monterey that's quite a lot on Coamps.

    Paul/Culebra

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