He Does Weather Routing, Not Miracles

Winter North Atlantic, not a good place for yachts.

I have been using weather routing companies for over 25 years, anytime I have had to make a tricky passage, particularly early or late in the season.

(Less so in recent years when improved models and less expensive satellite data have allowed me to develop and perfect my own routing procedures—see the blue box below the video.)

That said, I’m seeing a recent trend of some sailors assuming that a router is a miracle worker who can make any passage safe and even comfortable.

But, as I related in my last article, that’s not necessarily so, particularly when making a North Atlantic passage in November with winter coming on fast.

Worse still, voyagers are now regularly setting off on multi-day passages even in mid-winter. A trend that tells me they have completely missed the fact that a model that is consistently accurate out to five days in settled summer weather can be badly wrong just two days out from forecast time in less settled seasons.

But don’t take my word for it. Rather, let me hand you over to Ken Campbell, founder and senior router at Commander’s Weather. I know it’s 45 minutes long and you are busy, but this is really worth your time. Ken is the real deal, and he is showing big-time integrity in sharing the limitations in what he does and the data he (and we) use.

After you get done watching Ken, scroll down for some thoughts on how to learn about weather.

Learning About Weather

There are eight additional segments by other presenters (all of whom I admire) available from the same one day seminar.

Sounds like a great way to learn about weather, but, having watched all but one of the presentations, I found that the others suffered from the standard problem of one, or even two, day weather seminars: trying to cram too much in.

This results in attendees getting deluged with theory, that, if they are anything like me, will stay between their ears for a good five minutes, but coming away with little hard actionable information.

I mean seriously, Lee Chesneau, one of my weather heroes, would need most of two days to lay the ground work before he could teach us stuff we can use offshore, not 45 minutes.

I think most people who wish to get a basic grounding in weather for self-routing offshore would be better off to:

  1. Read Frank Singleton‘s Weather Handbook. It will only take you a couple of hours, at least for a first pass. I have never seen a better way to wrap your arms around the basic theory in the minimum possible time. (Get the paper version, graphics suck on Kindle.)
  2. Read our Weather Reception and Analysis Online Book, for a step-by-step how-to—another two hours or so.
  3. If you really want to get into it, move on to the “Damned Book“.

All that said, I did learn some useful stuff from most of the videos, so here are links to the others so you can judge for yourself:

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Meet the Author

John

John was born and brought up in Bermuda and started sailing as a child, racing locally and offshore before turning to cruising. He has sailed over 100,000 miles, most of it on his McCurdy & Rhodes 56, Morgan's Cloud, including eight ocean races to Bermuda, culminating in winning his class twice in the Newport Bermuda Race. He has skippered a series of voyages in the North Atlantic, the majority of which have been to the high latitudes. John has been helping others go voyaging by sharing his experience for twenty years, first in yachting magazines and, for the last 12 years, as co-editor/publisher of AAC.

13 comments… add one
  • Marc Dacey Dec 27, 2018, 1:23 pm

    Very good, John…and yes, “the damned book” is beside the bed…I can manage three pages or so of Hadley cell talk before I fade. The Singleton one is a doddle after that. I would be curious to learn what discovery or conclusion switched you from buying your routing to having confidence in your own abilities, because in either case, the point is to avoid directly whether the drogue works as advertised. Although in some cases, you want to use the edge of a decently large wind field to have 48 hours of fast passagemaking before the wave train gets unruly, and certainly ocean racers try to skate that line.
    As an aside, I wonder if Les Chesneau is recovering. I’ve attended two of his seminars, and you’re right, even though he is a great explainer of deep concepts, even two hours is not enough to appreciate the conceptualizations he grasps.

    • John Dec 28, 2018, 10:11 am

      Hi Marc,

      I have always taken a deep interest in the weather and done most of my own routing and departure decisions so there was no sharp transition from using a router to rolling my own, but rather a slow move to doing it myself more and more as I became more confident. That said, if faced with a really tricky passage like a fall trip to Bermuda I would still consult a router for a second opinion.

      • Marc Dacey Jan 1, 2019, 1:32 pm

        My skipper on a November delivery past Bermuda concurred and we were able to have the famous Herb H. route us daily between two systems full of rough stuff. Some places, I agree, are too complex and capable of rapid evolution to easily predict below the non-professional level. A similar place would be the southern end of Africa, I suspect.

  • GARRY CROTHERS Jan 1, 2019, 8:35 am

    Great videos, but it’s a pity there is no access to the slides. Especially the 500mb video by Les. Still way above my head.

    Garry

    • John Jan 1, 2019, 12:45 pm

      Hi Garry,

      Yes a slide stack would be nice. That said, I think the only really practical way to get our arms around the 500 mb and how to use it is Lee’s book.

  • PaddyB Jan 1, 2019, 10:22 am

    As ever thanks for article & links, such an interesting and important part of cruising. One problem I keep hitting is how can you quantify the accuracy of any forecast from observations? Done it before for a week or 2 just with a spreadsheet entering GFS forecast wind/gust & actuals from a local airport, the GFS did very well 🙂 But a load of work and not really practical. Anyway, the GEFS model seems interesting by seeing when the model starts to go a bit crazy with tiny differences in initial conditions – so is this a good indicator for reliability? This site has GEFS-SPEG and 500mB –
    http://mag.ncep.noaa.gov/model-guidance-model-parameter.php?group=Model%20Guidance&model=GEFS-SPAG&area=EUROPE&ps=area#
    .. and here does similar but with other options like surface wind –
    https://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=gefsts&MODELLTYP=2&BASE=-&VAR=uv10&HH=&ZOOM=0&ARCHIV=0&RES=0&WMO=03091&TABLE=99&MOUSE=0
    Then back to where we started – how do we know it helps? I’m guessing that a close spread of GEFS plots will suggest the model likely reliable up until the spread starts to go haywire. But could be wrong…. If anything then looking at the GEFS might at least make it more obvious to our modern ‘digital so must be right’ bias staring at one model run output and take onboard that they are all just most likely outputs from some extremely powerful computers.

    • John Jan 1, 2019, 12:47 pm

      Hi Paddy,

      Yes, accessing model accuracy is difficult. And, as you say, vital. Here’s a suggestion from a professional: https://www.morganscloud.com/2016/03/04/4-great-tips-from-a-professional-meteorologist/

      • Ernest Jan 1, 2019, 2:06 pm

        Yup, I remember last September when we were in the middle of the med, wondering why the weather did not obey to the grib model predictions 😉
        But then, in the med there is so much of land mass influence that a big weather pattern such as in the atlantic cannot be expected, except effects such as Meltemi or Mistral (which again are effected by weather on the mainland) which is a completely different topic.

      • craig burnside Jan 2, 2019, 6:40 am

        It’s a double edged sword, assessing weather models IMHO. First figure out a way to get a handle on the accuracy then figure out a way to assess the accuracy of your accuracy assessment 🙂 Neither easy – maybe you just got lucky!
        I’m drawn towards the more probabilistic approach from the GEFS model ensemble et al , like the Probabilistic Wind Speed Guidance from OPC instead of a one off best‐guess deterministic forecast with no data on certainty. Or rather both, like nav – anything and everything.
        Interesting piece here > https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017MS000999
        Pinching from that piece – maybe an idea for something to write about – ” embrace the concept of primacy of doubt”! Not just in weather, but in all things sailing, you can only control or predict the future in degrees of certainty, remembering this may help you focus a little better. Maybe 🙂

        • John Jan 3, 2019, 12:17 pm

          Hi Craig,

          Yes, I agree that there’s a lot to like about the Probabilistic Wind Speed Guidance: https://www.morganscloud.com/2018/01/29/great-new-weather-forecast-product/

          I have also already written a lot about the importance of understanding “the primacy of doubt”. Here’s just one example https://www.morganscloud.com/2011/09/29/lessons-in-hurricane-forecasting/

          That said, I agree, always a drum worth pounding.

          • PaddyB Jan 7, 2019, 6:59 am

            After some playing around in python, this might be of interest >
            http://www.moondogmoving.co.uk/sciwind.html
            Just a rough playaround but seems to work, the data is actual wind and forecast data for Scilly St Marys from UK Met Office. Click on the legends to turn on/off plots. This was chosen as it’s a low island. So far pretty accurate even 5 days out, which sort of talleys up with the GEFS. Plotting data is essential IMHO, not much chance of seeing the trends just string at a bunch of numbers. And every boat should have a Raspberry Pi to do all this fun stuff on 🙂

          • John Jan 7, 2019, 11:21 am

            Hi Paddy,

            Wow, that’s interesting, and comforting to.

  • PaddyB Jan 2, 2019, 6:52 am

    It’s a double edged sword, assessing weather models IMHO. First figure out a way to get a handle on the accuracy then figure out a way to assess the accuracy of your accuracy assessment 🙂 Neither easy – maybe you just got lucky!
    I’m drawn towards the more probabilistic approach from the GEFS model ensemble et al , like the Probabilistic Wind Speed Guidance from OPC instead of a one off best‐guess deterministic forecast with no data on certainty. Or rather both, like nav – anything and everything.
    Interesting piece here > https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017MS000999
    Pinching from that piece – maybe an idea for something to write about – ” embrace the concept of primacy of doubt”! Not just in weather, but in all things sailing, you can only control or predict the future in degrees of certainty, remembering this may help you focus a little better. Maybe 🙂

    EDIT – Sorry John, double posted after trying the back button to fix putting in the wrong name.

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