On an unusually sunny August Sunday, I had been looking forward to a day on the water, as this summer has seemed to be all-too-compressed after its cool, wet start. At the start of the day, there was a gentle, southerly breeze, which typically brings warm air and isn’t too strong. It perhaps feels even more gentle because it generally pushes boats home up into the heads of bays at the north ends of Maine’s many peninsulas. It also has the advantage of being more consistent as it blows over a large open area, or “fetch,” before reaching up into the nooks and crannies of the coast.
But after planning a trip in one direction that would take us out of the breeze, I watched as the wind shifted around to the west. This means that it comes over the land and thus is far less predictable and gustier depending on whether that land is forested or open in different spots. Perhaps it would be good to wait a little bit and see how things settled out. Well, not much later, it started to blow in from the north — completely opposite of where it had been coming from in the morning. This air was cooler and also gusty as it came over a varied landscape and out onto the water. At this point, it picked up strength and generated some serious waves. Maybe another day would be best to get out. Then finally, as the day hit its afternoon peak of sunshine and warmth, the wind just about dropped to nothing with the exception of a few puffs from the east. Perfect conditions for kayaking — finally, a decision was made. In sum, in a matter of fewer than eight hours, the wind direction had nearly come full circle.
As a follow-up to last week’s column about the Farmer’s Almanac’s wisdom in observing patterns in nature and letting them inform and help predict what might come next, I will say that I have seen this kind of wind shifting happen before. It is often at the end of the summer when the season can’t seem to figure out where it is headed. I know how to read the signs on the water like white caps or dark streaks that are clues to the wind’s strength or the direction that boats are facing that give clues to its direction. And I also know that wind has a lot to do with temperature and the differences between temperature on land versus that of the water. But I don’t understand specifically why these shifts occur at this time of year.
A simple definition of wind is that it is the movement of air from an area of high pressure to an area of low pressure. This is why, when a storm is coming in or when there is going to be a change in the weather, the wind often picks up. To get more complicated, you throw in terms like Coriolis and isobar. Maybe somehow Earth was spinning faster on that day and made the wind shift directions around the clock? Probably not, but I’m still not sure how to explain the multiple shifts in direction in the span of a single day.
I welcome input from any readers who have ideas on why this occurs and whether there is any predictability in its unpredictability. Because as someone who likes to get on or in the water as much as possible, wind, not temperature, is often the determining factor and one that I have yet to learn enough about.
Susan Olcott is the director of operations at Maine Coast Fishermen’s Association.
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