We had the coldest, wettest fall in recent memory. Boaters, albeit fewer, are still out there (like we are.) So, if weather like we’ve been seeing is the “new normal,” we should understand the forces at play. This column is about that.
The Lake Effect
We’ve all heard of the “lake effect,” where the Great Lakes dump so much snow on upstate New York and nearby states. Snow accumulations of 10 to 12 feet over the course of the winter in Buffalo are not unusual. The phenomenon occurs when cold air flows over the relatively warm lakes. The relative heat of the lakes leads to warming of the lowest levels of the atmosphere, which promotes rising air. When air rises in the atmosphere, it is cooled, and if enough upward motion (and thus enough cooling) results, then the air will reach its dew point and condensation will occur, leading to cloud development. Eventually the clouds will produce precipitation.
The Ocean Effect
Why doesn’t that happen here, at the seashore, where all the same characteristics are at hand: warmer water, winds and cold air? In fact, it does. The ocean effect just doesn’t get as much media attention since nobody lives over the ocean, and there are no roads to get clogged by snow. Also, the temperature gradient isn’t as great since we don’t get as much of that Canadian cold air as they do upstate.
Since most of us aren’t boating during the winter months, it isn’t much of an issue. However, with the extremes of weather we’ve been seeing, we can see the ocean effect both in the fall and in the spring. And what doesn’t fall as snow falls as rain — and plenty of it, as we’ve seen.
Clear skies over the mainland and plenty of cloud cover over the ocean . . . and seashore communities. That would be us.
The basics are very similar to the lake effect scenario; thus, it will occur when rather cold air flows over the warmer ocean waters. Once the air has been over the water long enough (i.e. a bit offshore), it warms and rises, and clouds will form. And, if the temperature difference between the air and the water is large enough, precipitation will develop from these clouds. This situation will frequently occur behind a cold front which has moved off shore.
Typically, a cold front will be accompanied by showers, then clearing skies are likely after the front has passed and the colder and drier air mass moves in. Forecasts in coastal locations will indicate this progression of events, but offshore, the situation may be different with clearing skies initially followed by the ocean effect conditions described above. And remember, all ye seaside residents, Montauk is 130 miles out at sea, relative to New York City. These long shorelines of the northeast can create “at sea” weather conditions, right here on land.
So, if you happen to be operating over the Atlantic waters this fall (or spring) when a particularly cold air mass follows a cold front, be aware that despite forecasts of clearing, windy, and colder conditions, it is very likely that considerable clouds will be experienced offshore, with the real potential for serious rain, or snow, at times.
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