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Current position of the SSV Robert C. Seamans. Click on the vessel to view position history. Use the tools, top right, to change the map style or view data layers.


SEA Currents: SSV Robert C. Seamans

December 02, 2018

Pattern and Chaos

Elliot Rappaport, Master

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The Maine Delegation.

Ship's Log

Current Position
35 47S x 178 39W

Course & Speed
220/5

Sail Plan
4 Lowers

Weather
Winds NE Force 5, Overcast Sky

Souls on board

Bob McDevitt is a semi-retired senior forecaster from the Kiwi national weather service that any visiting sailor would do well to meet. He goes by the pen name MetBob.  Among other things, Bob is the author of something called The Mariner's MetPack, the first book that I ever read on weather in the Southwest Pacific. I had to read it a few times to digest everything that was there. It's a narrow spiral-bound thing, barely thicker than the assembly manual for a folding couch from IKEA. But like your piece of convertible furniture, the atmosphere around New Zealand is a complex mesh of moving parts that it's best to understand comprehensively if you can manage.

There's not much land in the latitudes between New Zealand and Antarctica - just the Southern Ocean, a cold band of stormy water on a steady course around the globe, driven along by near-constant westerly winds. New Zealand itself, rather like California, spans a south-to-north belt between the cool temperate latitudes and the subtropics, where there's a reliable supply of warm air and sunshine. North of there is the tropical South Pacific. Fiji. Tonga. Vanuatu - all places with evocative names surrounded by the warmest air and water on earth.

Like eddylines on a river, these distinct and very different air masses swirl past each other and make the weather. Cold polar air pushes north into warm air, which rises, cools, and makes rain from condensation. The barometer falls, wind rushes in. Blasts of warm dry air drift off of Australia and hatch into gales over the Tasman Sea. The tropics heat up as spring becomes summer, sending moisture and energy south in long skeins of water vapor.

Far away storms send swells for miles across empty ocean. The ship rolls deeply on their arrival and I hear pots and pans somewhere sliding across a counter before crashing to rest. Unlike our cookware, the people aboard have adapted, their progress about the ship now a dance of handholds, hesitations, and small course changes to avoid accidental contact in the narrow passageways.

Alongside us in the wind, the birds ride along through it all like they live there.

This has been a trip of wind and motion, characterized by a parade of low pressure systems that have provided us with great sailing breezes and ample opportunity to wear our boots and raingear. It is the unsettled weather of spring, the down-under analog of the early June rainstorms in Boston. Is this spring more unsettled than usual? Perhaps, says MetBob in his biweekly blog (see metbob.com)-Perhaps the early evolutions of an El Nino are working to destabilize the local atmosphere and keeping certain parts of the local ocean warmer than normal-- or perhaps not. Weather, he likes to say, is a mixture of pattern and chaos. You might say the same for sailing.  

-Elliot Rappaport, Master

Categories: Robert C. Seamans,The Global Ocean: New Zealand, • Topics: s283  weather  new zealand • (0) Comments
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