Wednesday, November 7, 2012

The Weather Window

Here we are, anchored in Tonga. We are surrounded by coral reefs and tropical vegetation. Sharks and rays swim lazily by. We can snorkel into caves filled with fish below and bats above. And there are boats aplenty. And what are all of these people doing in this natural paradise? Let's listen in to the chatter around the harbor.

"Did you get a grib file today?"
"Hmm, what do you think about that low that's forming? Is it going to hit us squarely, or push off to the west?"
"I don't like the look of those isobars."
"Did you see the wave height at 25 S 176 W?"

Right. Everyone is talking about the weather. While they scrape the algae off their hulls, when they run into friends on the reef, over a cold one at five o'clock.

Farmers have a well-deserved reputation for talking about the weather. No report from home is complete unless we get an update on my father-in-law's soya beans. But I would suggest that cruisers are worse, if only because they have more components to compare.

Farmers: fixed land area, usually measured in acres. Farm: not moving. Primarily concerned with crops getting too much/little sun/rain. Experts at riding the razor's edge of how wet a field can be before you can no longer drive heavy equipment on it.

Cruisers: moving area, often measured in thousands of square miles. Boat always moving, even at anchor. Need to ensure boat will not hit anything else, ever. Need to watch wind speed, wind direction, barometric pressure, highs, lows, troughs, convergence zones, convection, wave height, wave direction... Concerned with (in priority sequence): 1. Arriving; 2. Arriving safely; 3. Arriving safely with the minimum of damage to the boat.

There is always weather-talk going on in the cruising world. Paying attention to sailing conditions can mean the difference between having a lovely outing and losing your boat. So, fair enough. But right now, it is an obsession, and everyone is out to earn their amateur meterorologist badge. A massive information collection effort is underway. We listen to the experts from New Zealand on the SSB. We get the text files and gribs and weatherfaxes from authorities around the Pacific. And heaven help you if you go to town, because the moment you return, the whole anchorage wants to know the latest from Passageweather.

Why? Cyclone season has begun in the Southern Hemisphere - technically if not literally - and most of us in Tonga are headed to New Zealand for the duration. The north island is about 1200 NM from Vava'u, so we have about a 10-day passage ahead of us. And everyone is waiting for the perfect time - the weather window - to leave. Even the bureaucrats watch the weather; a friend of ours once tried to check out of an island group and was solemnly told by the customs official that, "Sir, the weather window is closed."

It is a game of Should I Stay or Should I Go? A big low is coming through within the next couple of days, so there was a mass exodus on the weekend as people tried to get ahead of it. We decided we would rather wait it out here, but that doesn't mean we can sit back and sip pina coladas. Instead, we were left with the question of where to anchor. Is our anchorage appropriate for the coming winds? Do we have good holding? What is our likely wind direction going to be? How much fetch is going to build? When your home moves, there is a lot to consider if you want it to stay where you put it.

We watch the weather. We subscribe to grib files, and get weatherfaxes when we can. We listen to expert reports on the SSB, and, when we go, we will join a net that gives us position-specific weather information. In short, we try to make good decisions based on the information available. And I've been as guilty as anyone for asking for the latest news. But I try not to make myself crazy over it, because there is no weather service on Earth that can tell me with perfect certainty what kind of weather I'll enjoy during the entire 10 day trip to New Zealand. We'll choose the best window we can, and deal with changes as they arise.

And, when we visit home again, we will nod in sympathetic understanding when Farmer Grandpa is frustrated because the summer has been too hot and his crops are withering in the fields. We know very well what a pain the weather can be.

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5 comments:

Anonymous said...

I sympathize. Weather, as you are aware is near & dear to my heart: the Weather Channel one of my faves. If only Dave Phillips mystical prediction powers could reach out as far west as you are now moored.

We will be watching your next leg with great interest.
Love Mom

Kate said...

Heard from mom the weather is diecy now. Thinking of of and hoping for good weather to come your way.

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