Trev’s Forecast for next 7 Days from 25 May
Finally after some weeks of low wind, I have been able to get some windsurfing in and teach a friend this skilled sport. Windsurfing is a great way to stay healthy and feel the real power of the wind. The power in the wind varies with the mathematical cube of the wind speed. So a wind speed of 40km per hour has 8 times the power in the wind compared to a wind speed 20 km per hour. That’s a huge change and we compensate by using smaller sails.
Global heating is causing more extremes storms and associated wind speeds. The Saffir-Simpson scale is used to define the wind speed ranges for various storm and cyclone events. Here’s a link https://en.wikipedia.org/wiki/Saffir%E2%80%93Simpson_scale#:~:text=The%20highest%20classification%20in%20the,of%20at%20least%20157%20mph.
A Category 2 cyclone might have an average wind power of 53 kilowatts per square metre of approaching wind, about the maximum power of a small car pushing on each square metre of your walls, windows and roof. A category 5 cyclone is almost 10 times more.
|Velocity of the Wind averaged over 1 minute 10 metres above the ground||Power in the Wind|
|Weather Conditions||km/hr||knots||metres per second||Kilowatts per square meter|
|Category 2 Cyclone||160||86.4||44.4||53.1|
|Category 5 Cyclone||320||172.8||88.9||424.9|
That’s enough for the physics of wind power.
So what’s happening over the next week? Winds are turning south and getting stronger on Saturday through to Monday. This is due to fairly intense high and low pressure systems to the south of us. Temperatures will fall a little from Friday with minimums around 11C and maximums around 22C. Don’t expect any rain as the winds come over colder water which is harder to evaporate.
So watch your hats don’t blow off.
See ya next week. Trev The Weatherman
Source: www.seabreeze.com.au and Bureau of Meteorology