Weather or Not, Part 2

Last Saturday and Sunday (3/15 + 3/16) we took the advanced weather course with Lee Chesneau.  This builds on what we learned the previous weekend and really gets into the meat of weather forecasting.  There were only four students for this weekend so it was kinda like private instruction, one-on-one almost.  We concentrated on 500 mB (millibar) charts.  These show the lower elevation of the Jet Stream which has the biggest affect on surface weather.  We also covered tropical storms and hurricanes, waves and a whole bunch more.

Many cruising sailors rely on GRIB files for making their own weather predictions.  These are computer models that show wind speed and direction.  What they don't show is high and low pressure systems and fronts.  Without this information you can't reliably predict what the weather will be doing in the next few days.  Sailboats are slow moving even though sometimes it feels like you're really screaming along.  I've seen our boat make 10.5 knots through the water but that's only about 12 mph.  We average about 6 knots.  You can ride a bicycle faster than that.  Most people can run faster than that with the average running speed in a sprint being 12 to 15 mph.  Now picture being on a sailboat out in the middle of the Atlantic Ocean with the closest land about a thousand miles away.  If a storm comes up unexpectedly you can't duck into a protective creek and wait it out.  And a storm on the ocean can push up some pretty substantial waves.  For the safety of the boat and it's crew it's best to avoid bad weather if you can and if you're only going 6 knots you had better change your course way in advance, long before the bad weather will affect you.

To know what the weather is going to be doing in 24, 48 or 96 hours you need NOAA's "surface weather" analysis and prediction charts (Click here).  To make your own weather analysis or to understand what the surface charts are based on you also really need the 500 mBar charts (Click here) that show what the Jet Stream is doing.  These are what all weather predictions are based on.  There are highs and lows (500 mB pressure elevations) and troughs and ridges that affect everything going on at the surface.  If you know how to read this and relate it to the surface charts you can reliably make your own decisions about the weather and how you should deal with it.  NOAA has a really excellent explanation of the 500mB chart (Click here).

This appeals to me for several reasons.  First and foremost, I don't really like the idea of putting my life in someone else's hands.  I want to be independent and responsible for my own safety while I'm out at sea.  I also don't want to pay the extravagant fees for a weather router and have to rely on them when I'm just as able to do it myself and can do it for free.  We used a weather router on our trip to Bermuda and it cost us $250 per boat and only one of us had contact with them.  That was $500 for a three week voyage.  Now you do get a lot of information for that $500 including where the eddies are in the Gulf Stream and how to take advantage of them.  You also get someone telling you what course to take, when to change course and what kind of weather to expect.  I don't know what the annual fee is for 24/7 weather coverage but I'm pretty sure it's way more than I want spend.  I can do this myself and make use of the weather information at any time of the day or night for free.  I can also use the money I save by not hiring a router and buy a single side band radio so I can get the surface and 500 mBar charts no matter where I am on the planet.

The class was not cheap at $125 per person per day but it takes up every bit of 8 hours per day for 32 hours total.  Many folks only signed on for part of the course.  One guy was going to be sailing his boat with three others in a race from Annapolis to Bermuda (the A to B race).  He had his entire crew there for the first day so they got the basics of weather and cloud identification.  None of them showed up for the rest of the course though and I think they really missed out. Even if only one of them came they would have learned how to read the charts and predict the weather.  There was another boat owner in the same race and he stayed for the whole class.  He'll have a distinct advantage and also that feeling of self reliance you get when you have the necessary knowledge to take care of yourself.

What I'm trying to say here is if you go out sailing on the oceans of the world you absolutely have to know what's going on with the weather.  Before the days of satellites sailors had a good knowledge of weather using clouds and the wind to predict what was coming up in the near future, usually less than 24 hours.  They still got hit by bad storms and if they were in the path of a hurricane there was no way to avoid it.  These days there's information available to every one of us to reliably predict the weather as much as four days in advance.  If we're averaging 150 miles per day that's 600 miles over four days, or ten full degrees of latitude on a mariners chart, and that's plenty of room to avoid bad weather.

We're totally jazzed about the amount of info we picked up.  We walk outside and try to figure out what kinds of clouds those are and what weather they're bringing.  We downloaded the 96 hour forecast this past week and payed attention to each day's weather to see if it all made sense.  It did!  I think the challenge now is to keep at it and practice/study every day.  We'll eventually be able to identify what we're looking at without peaking at the cheat sheets.