Now that we've seen the destructive force that the wind can have when it topples trees (see the earlier post about the tree falling in our yard), Austin was interested to know a little bit more about where this evening's strong wind was coming from. This required that we did a bit of investigating using the Environment Canada web site. The best information is found on the Marine Forecast pages for the Georgia Strait South of Nanaimo.
First we took a look at the detailed weather reports from the local marine weather station at Pt. Atkinson.
From this we could see that the average wind speed had been increasing all afternoon and peaking at 1700 (5pm). However, the gusts had continued to increase all the way to a top speed of 50 knots (approx 90Km/h) between 8pm and 9pm. The other thing that we noticed was that the temperature had been dropping all evening which is what you'd expect once the sun goes down but why was it rising again? Time to break out more reports to see what was going on in the bigger picture.
By going to the Environment Canada Analysis Charts we can see a large low pressure system moving in from the North West. The contour lines indicate the rate in change of air pressure and can be thought of as a slope with the air moving down it like water. The closer together the lines, the steeper the slope and the faster the wind. So now we know what's creating all that wind tonight. But why is the temperature rising even though the sun's gone down?
Looking at the Analysis Chart a little more we can see some thick, curved lines spiraling out from the big L (for Low) with triangles and semi-circles on one of the lines. These indicate warm and cold fronts where the triangles represent a cold front and the semi-circle bumps represent warm fronts. Austin could see that on this chart there is a warm front just off the coast of Vancouver Island and Washington State. This is bringing warm air to us which is causing the temperature to rise.
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