Presentation on theme: "Boating Course Weather Canadian Power & Sail Squadrons."— Presentation transcript:
Boating Course Weather Canadian Power & Sail Squadrons
General As an operator of a small vessel you can not safely ignore the weather. Even an elementary knowledge of theoretical meteorology can add greatly to piece of mind, comfort, and competence while afloat.
There are professionals whose job it is to collect, analyse, and interpret weather data and to disseminate this information to users.
The object of this section is to provide a basic explanation of weather hazards and to describe marine weather forecasts and warnings, and how to obtain them.
Publications that will be useful on the British Columbia coast Marine Weather Hazards Manual and The Wind Came All Ways – Owen Lange
Mariners Guide – West Coast Weather Services. These publications are available through Environment Canadas Meteorological Service These publications are available through Environment Canadas Meteorological Service
For those who wish further instruction in meteorology, the CPS Fundamentals of Weather is recommended.
This presentation is available for download from my personal web site. The address is: weathercat.ca
Weather Hazards Five Phenomena that can be hazardous to operators of small boats.
Wind – The atmosphere in motion. Measured in knots for marine use ( 1.15mph, 1.85km/h ). Winds may be steady or gusty. A gust is a sudden increase in wind speed of 10 knots or more, lasting only a few seconds.
A squall is an increase in speed that lasts 2 minutes or more. Both gusts and squalls may also be accompanied by a change in wind direction.
A cats paw is the name given to the patches of ripples betraying the presence of slightly more wind on an almost calm day.
In a similar manner, an approaching patch of darker, disturbed water on a windy day can reveal the approach of a gust or a squall when there may be no other clue to its presence.
Only apparent wind is felt on a moving boat. This is a combination of the wind and the boats movement.
An example would be a wind from directly astern. In this case the boats speed is subtracted from the true wind speed to give the apparent wind speed.
There is a very good article on the web relating to apparent wind, you can find it at the following address: http://johnellsworth.com/writing/nautical/understand_appwind/understand_appwind.html
Wind without waves is usually only a problem when manoeuvring in a confined area. If a boat is well secured, it would take very strong winds to cause damage.
Waves – Energy transferred from the air to the water. Note that the water will move at only about 3% of the wind speed.
Wind Waves – generated by the wind blowing over the water surface. Swell Waves – left over wind waves that have moved away from their source area.
Wind wave heights are directly related to the wind speed, time (duration) of the wind, and distance (fetch) it blows over the water in a straight line.
Stronger winds require shorter fetches and durations to raise the same wave, and a storm force wind can produce 1-2m waves only a mile offshore in about 15 minutes.
Wave Trains Significant wave height is the average of the highest third of the waves Most frequent wave height………0.5 X sig wave height Average wave height……………..0.6 X sig wave height One wave in 10…………………..1.3 X sig wave height One wave in about 1000 …………1.7 X sig wave height Maximum wave …………………2.0 X sig wave height
South Coast 03 - Fanny Island 03 - Fanny Island 21 - Sheringham Point 21 - Sheringham Point 22 - Tofino 22 - Tofino 23 - Estevan Point 23 - Estevan Point 24 - Nootka 24 - Nootka 25 - Solander Island 25 - Solander Island 26 - Quatsino 26 - Quatsino 27 - Sartine Island 27 - Sartine Island 28 - Pine island 28 - Pine island 29 - Herbert Island 29 - Herbert Island 30 - Egg Island 30 - Egg Island 31 - La Perouse Bank ( Weather Buoy) 31 - La Perouse Bank ( Weather Buoy) 32 - South Brooks (Weather Buoy) 32 - South Brooks (Weather Buoy) 33 - Cape Scott (MAREP Station) 33 - Cape Scott (MAREP Station) 61 - Chatham Point 61 - Chatham Point North, Middle and South Nomad Buoys not shown North, Middle and South Nomad Buoys not shown
Georgia Basin Weather Buoys and Stations 01 - Sentry Shoal (Weather Buoy) 01 - Sentry Shoal (Weather Buoy) 02 - Halibut Bank (Weather Buoy) 02 - Halibut Bank (Weather Buoy) 03 - Fanny Island 03 - Fanny Island 04 - Cape Mudge 04 - Cape Mudge 05 - Campbell River 05 - Campbell River 06 - Powell River 06 - Powell River 07 - Grief Point 07 - Grief Point 08 - Chrome Island 08 - Chrome Island 09 - Port Alberni 09 - Port Alberni 10 - Sisters Island 10 - Sisters Island 11 - Ballenas Island 11 - Ballenas Island
Georgia Basin Weather Buoys and Stations 12 - Entrance Island 12 - Entrance Island 13 - Merry Island 13 - Merry Island 14 - Pam Rocks 14 - Pam Rocks 15 - Point Atkinson 15 - Point Atkinson 16 - Sand Heads 16 - Sand Heads 17 - East Point 17 - East Point 18 - Kelp Reef 18 - Kelp Reef 19 - Discovery Island 19 - Discovery Island 20 - Race Rocks 20 - Race Rocks 21 - Sheringham Point 21 - Sheringham Point 61 - Chatham Point 61 - Chatham Point
Synopsis and Forecasts Issued at 0400, 1030, 1600 and 2130 hours Forecast valid for 24 hours- updated if conditions change Securite, Securite on Channel 16, Switch to WX or 21B
Synopsis and Outlook Wind Speed Terms Light 0 to 11 knots Moderate 12 to 19 knots Strong 20-33 knots Gales 34-47 knots Storm 48-63 knots Hurricane 64 knots or more
Synopsis and Forecasts- VHF Weather Channels Victoria- WX 3, 21B Strait of Georgia South Strait of Georgia South Howe Sound Howe Sound Juan de Fuca Strait Juan de Fuca Strait Haro Strait Haro Strait West Coast Vancouver Island South West Coast Vancouver Island South Comox- WX1, WX3, 21B South End of Texada Island to Northern Vancouver Island South End of Texada Island to Northern Vancouver Island Adjacent Mainland Adjacent Mainland
Synopsis and Forecasts- VHF Weather Channels Tofino- WX1, WX2, WX3, 21B West Coast Vancouver Island Prince Rupert- WX1, WX2, WX3, 21B North Coast, Queen Charlottes WX 1 (162.55 MHz), WX 2 (162.40 MHz), WX 3 (162.475MHZ), 21B (161.65 MHz)
Synopsis and Forecasts- Sources Continuous Marine Broadcast – Phone Mt. Helmcken – 250-363-6880 Mt. Helmcken – 250-363-6880 Bowen Island/Mt Parke – 250-363-6492 Bowen Island/Mt Parke – 250-363-6492 Comox – South Area – 250-339-0748 Comox – South Area – 250-339-0748 Comox – North Area – 250-974-5305 Comox – North Area – 250-974-5305 Tofino – 250-726-3415 Tofino – 250-726-3415
Marine Weather Information - phone Nanaimo -250-245-8899 or 8877 Nanaimo -250-245-8899 or 8877 Campbell River -250-286-3575 Campbell River -250-286-3575 Port Hardy-250-949-7148 Port Hardy-250-949-7148 Victoria-250-363-6717, 250-363-6492 Victoria-250-363-6717, 250-363-6492 Vancouver-604-666-3655 Vancouver-604-666-3655Television The Weather Network The Weather NetworkInternet http://www.weatheroffice.gc.ca/ http://www.weatheroffice.gc.ca/
Marine Warnings Strong Wind Warning (20-33 knots) Issued for Southern inner coastal waters between Good Friday and Rememberance Day. Gale Warning (34-47 knots)
Storm Warning (48-63 knots) Hurricane Force Wind Warning (64 knots or greater) Monitor VHF Channel 16, Securite, Securite Switch to WX or 21B
Weather Procedures for Safe Boating Before Setting out: Check current weather and sea conditions by contacting other vessels in your area of interest. Obtain the latest marine forecast and warnings for your region.
Obtain tide and current information. Decide if you and your boat can navigate safely in the weather and sea conditions expected.
While Under Way Monitor Channel 16 for announcements of CCG weather broadcasts.
Periodically obtain weather information from Weatheradio Canada. Monitor the water ahead for signs of wind changes.
Note progressive changes in the sky, and monitor the direction the clouds are moving. Note changes in wind speed and direction.
Note changes in waves or swell. Recording all these observations in a log book is a good way of quickly building up a store of knowledge of your area.
Weather Tips Manoeuvring When manoeuvring in a confined area at low speeds, turning into the wind will considerably reduce the amount of room required to make the turn, compared with turning downwind.
Clouds Approaching showers may include wind gusts or squalls. Rapid building of large cauliflower- shaped clouds indicate a possible thunderstorm within an hour or so.
The approach of dark, rolling, threatening clouds may herald a thunderstorm within the next few minutes.
Cumulonimbus (CB) Base of the Cloud with Mammatus