clouds

Marine Weather Workshop Report

Let’s face it: talking about the weather can be a dry or wet subject.

Not so at the April 14th Marine Weather Workshop with Tony Merry from the Pender Island Squadron.
13 eager students gathered in the Community Hall on Saturna Island to talk about the weather.
The weather man brought some good weather humor with him too.

Here are some weather nuggets for those that missed this Marine Weather Course with Tony Merry, hosted by KayakingSkills.com:

The sun causes our weather.

We are surrounded by air which is 78% nitrogen and only about 21% oxygen.
So, when Tony fills his car tires with air, he uses 78% nitrogen 😊

Without water as vapour, liquid or solid, there would be no weather.

We looked at a surface analysis NOAA (National Oceanic and Atmospheric Administration) printout that gives a good picture of the weather that is approaching from the Pacific. We learned to make more sense of this surface analysis with its isobars, fronts, highs and lows.

Cold fronts move faster than warm fronts and when they catch up, we end up with a TROWAL (Trough of warm air aloft).

Wind moves from high to low pressure.

Isobars are 4 mbar apart. The closer the lines of the isobars, the stronger the winds.

In the Southern Gulf Islands, the prevailing winds are South Easterlies (wind moves from whatever direction is indicated).

Buys-Ballot’s Law: “If you stand with your back to the wind in the Northern Hemisphere, pressure is lower to your left.”

Wave height is influenced mostly by wind speed, duration of wind and fetch. Fetch is the distance the wind blows over an open water surface. The largest waves will be generated when the wind speed, time frame, and fetch are greatest.

Clouds are mainly defined by the height of their base above the ground and their shape.
High clouds are composed of ice crystals, giving them a white and bright appearance. Medium and lower hanging clouds may include ice crystals, but often mostly water droplets and look greyer.
Clouds high in the sky give information about future weather tendencies, lower clouds are relevant for present weather conditions.

Whether you are inside the fog or looking at a low-lying cloud is merely a matter of perspective 😊

To determine the height of cumulus clouds, check this out: is the cloud element bigger or smaller than your 3 fingers held next to each other at armlength? Bigger: it is lower (stratocumulus). Smaller: it is higher (altocumulus).

And then there are clouds of vertical development that we need to look out for…

Hail only comes from cumulonimbus clouds. Therefore, we know what clouds were over Saturna Island on April 7th (2018), when hail fell and thunder and lightning hit Saturna Island. Though rare for thunder and lightning to be quite as close to home here, it does happen.

KayakingSkills.com occasionally hosts workshops and speakers about being safe on the water; especially interesting for kayakers and boaters. Drop us an email if you like to be informed about future events. All kayaking courses conducted by KayakingSkills.com cover a relevant marine weather overview also.

Posted in Marine Safety, Weather and tagged , , .

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