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Test Yourself - Online Exam RYA Day Skipper and Yachtmaster
Feedback is welcome Click on for on line Colregs test and CEVNI test and to buy Weather, Colregs, VHF and more navigation skills charts Test Yourself - Online Exam RYA Day Skipper and Yachtmaster ICC / BSAC Seamanship Met - Weather Exam / Assessment Meteorology Weather at Sea Mouse click or Page Down to start © SKYSAILTRAINING 2012
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SKYSAIL SKILLS CHARTS http://www. btinternet. com/~keith
Extracts from Skysail Skills Charts on the essential navigation subjects – all summarised on A4 laminated charts. For full details click link above Day Skipper VHF Weather Chartwork
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Before the Meteorology tests
Here is the full weather presentation if you need it (2MB):
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Forecasts Where would you find weather forecasts? On land At sea TV
National radio Local radio Newspapers Teletext Web Barometer Mobile phone BBC radio Coastguard VHF Metfax to PC Navtex Barometer Observation Mobile phone Day Skipper Weather
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Forecasts What is the sequence of the Shipping Forecast? Gale warnings
General Synopsis at time of issue Wind now - direction and force Wind later Sea state Weather - fair, rain, etc Visibility Day Skipper Weather
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Shipping Forecast Terms
What do the following mean? Imminent Soon Later Within 6 hours of the time of issue of the forecast 6 to 12 hours After 12 hours Very poor Poor Moderate Good < 1000 metres visibility < 2 Miles Moderate Rough Very rough Wave height m 2 - 5 Miles 1.25 – 2.5 > 5 Miles 2.5 – 4.0 Fair No precipitation 4.0 – 6.0 Day Skipper Weather
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Wave height What factors affect wave height? Wind speed and duration
1 2 3 4 5 Wind speed and duration Tide speed and direction wind against tide gives higher waves Depth of water Fetch - the distance over which the wind blows Swell - the wave pattern before the current weather Day Skipper Weather
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Wind How do you define the following? Direction
Cyclonic Veering Backing Direction from which wind blows Rapid changes in wind direction (Possibly at the centre of a depression) Changing direction clockwise Changing direction anticlockwise Day Skipper Weather
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A gale (whether the change is rising or falling)
Pressure / Wind / Waves What is likely if the pressure has changed by 6 millibars in the last 3 hours? A gale (whether the change is rising or falling) From these descriptions estimate what the Beaufort wind force is: a) Moderate waves, many white crests. b) Sea heaps up, spray, breaking waves, foam blows in streaks. Force knots Force knots Day Skipper Weather
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Fronts / Buys Ballot How do you define the following? Occluded Front
Warm Front Cool air Warm air Advancing cold air Cold Front Occluded Front How do you define the following? Occluded Front Buys Ballot’s Law An occluded front is formed when the faster moving cold front overtakes and merges with the warm front. Typical weather is cloudy, with light rain and poor visibility in the Northern Hemisphere, if you stand with your back to the wind, the area of low pressure is to your left and the high pressure to the right. Day Skipper Weather
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Depressions H L What is the weather and wind at A, B, C, D? D A C B
Fair Light winds H D Light Rain Wind backs Heavy rain Poor visibility Wind increases L A Clear, bright Showers Good visibility Wind veers and increases Broken cloud Showers Very poor visibility Wind steady C B Cumulonimbus Heavy rain Thunder Lightning Squalls Day Skipper Weather
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Depressions H L What is the weather at A, B, C, D, E, F, H? Warm front
Cold front Warm front Warm sector F Fair Light winds Cirrus, fair Cirrostratus A H Altostratus Light Rain Wind backs Pressure falls B L Clear, bright. Cumulus Showers Good visibility except in showers. Wind veers sharply and increases. Pressure rises Nimbostratus Heavy rain Poor visibility Wind increases C Broken cloud Alto cumulus Showers Very poor visibility Wind veers, steady Pressure is steady D Cumulonimbus Heavy rain Lightning Thunder Squalls E Yachtmaster Meteorology
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Clouds What type of clouds and what do they signify?
Cirrus - can indicate an approaching depression Cumulonimbus - thundercloud, squally, lightning. Cold front. Cumulus - fair weather Yachtmaster Meteorology
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Sea Breezes What is a sea breeze? What causes it?
Sea breezes are caused by unequal heating of land and sea surfaces. During the day, especially in summer, solar radiation heats the land surface to become warmer than the sea surface which stays cold all summer. The temperature difference rises to a maximum around mid afternoon. The warm air rises over the land and cool air from the sea is drawn in, setting up an onshore wind. As the heating effect increases, the sea breeze strengthens, and may reach 15 knots (F4). A land breeze develops at night as the land cools relative to the sea and an opposite but weaker circulation sets up. What is a sea breeze? What causes it? Yachtmaster Meteorology
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Sea Fog What causes sea fog? In which season is it most frequent?
It occurs when warm air flows over a cold sea surface (advection flow). What causes sea fog? In which season is it most frequent? Will there be wind? What makes it clear? Spring / early summer when the sea is still cold. Yes A change in wind direction or sea temperature Yachtmaster Meteorology
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Land Fog It occurs when land cools What causes land fog?
overnight by radiation of heat. The air cools and moisture condenses to form fog. What causes land fog? In which season is it most frequent? Will there be wind? What makes it clear? Late Autumn / Winter when pressure is high and there is no cloud. No. Land fog can form in valleys and drift out to sea. The heat of the sun the following morning. Yachtmaster Meteorology
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Coastal Winds With the gradient wind as shown, what will the wind be on the coast lines? Gradient wind Winds diverge. Coastal wind is weaker Sea wind Land wind Winds converge. Coastal wind is stronger Land wind Sea wind Yachtmaster Meteorology
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PASSAGE OF A DEPRESSION
Cold Front Cirrocumulus Cirrus Warm Sector Cirrostratus Cumulonimbus Altocumulus Altostratus Cold Air Warm Air Nimbostratus Warm Front Fractostratus Cumulus 20,000 ft Stratocumulus Cumulus Cool Air West East 200 M 300 M 600 M WIND Strong gusts Veering sharply Squalls Steady Veering Backing & increasing PRESSURE Rising, then steady Rising quickly Falling RAIN Sunny, squally showers Heavy rain, thunder, hail Light rain Drizzle Becoming heavier and prolonged VISIBILITY Good except in showers Poor in rain Poor Fog Poor Deteriorating TEMP Cold Falls Warm Rising
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A B L H D L H C Pressure Systems What is the likely wind at A, B, C ?
Variable, light NW, strong L Deep depression D SW, light SSE, strong H C Yachtmaster Meteorology
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END Warm front Cold front Warm sector 976 968 984 960 1000 992
Yachtmaster Meteorology
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