© SKYSAILTRAINING 2012

1. Feedback is welcome Click on www.skysailtraining.co.uk for on line Colregs test and CEVNI test and to buy Weather, Colregs, VHF and more navigation skills charts Test Yourself - Online ExamRYA Day Skipper and Yachtmaster ICC / BSAC SeamanshipMet - Weather Exam / Assessment MeteorologyWeather at SeaMouse click or Page Down to start © SKYSAILTRAINING 2012

2. SKYSAIL SKILLS CHARTShttp://www.btinternet.com/~keith.bater/navigation_skills_charts.htm 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

3. Before the Meteorology tests • Here is the full weather presentation if you need it (2MB): http://www.btinternet.com/~keith.bater/weather_for_yachtmaster_day_skipper_course.pdf

4. 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

5. 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

6. of the time of issue of the forecast Wave height m Moderate Rough Very rough Shipping Forecast Terms What do the following mean? Imminent Soon Later Within 6 hours 6 to 12 hours After 12 hours Very poor Poor Moderate Good < 1000 metres visibility < 2 Miles 1.25 – 2.5 2 - 5 Miles > 5 Miles 2.5 – 4.0 Fair No precipitation 4.0 – 6.0 Day Skipper Weather

7. Wave height What factors affect wave height? 1 2 3 4 5 Wind speed and duration Tide speed and directionwind 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

8. 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

9. 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 5 17-21 knots Force 7 28-33 knots Day Skipper Weather

10. OccludedFront Advancing cold air Cool air Warm Front Cold Front Warm air Fronts / Buys Ballot 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

11. D Light RainWind backs H FairLight winds Heavy rainPoor visibilityWind increases Clear, brightShowersGood visibilityWind veers and increases Broken cloudShowersVery poor visibilityWind steady Depressions What is the weather and wind at A, B, C, D? L A C B CumulonimbusHeavy rainThunder LightningSqualls Day Skipper Weather

12. Cirrus, fair FairLight winds Cirrostratus AltostratusLight RainWind backsPressure falls H Clear, bright.Cumulus ShowersGood visibility except in showers.Wind veers sharply and increases.Pressure rises Warmfront Broken cloudAlto cumulusShowersVery poor visibilityWind veers, steadyPressure is steady F Coldfront Warmsector Depressions What is the weather at A, B, C, D, E, F, H? A B L NimbostratusHeavy rainPoor visibilityWind increases C D CumulonimbusHeavy rainLightning ThunderSqualls E Yachtmaster Meteorology

13. 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

14. 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.  Sea Breezes What is a sea breeze? What causes it? Yachtmaster Meteorology

15. Sea Fog • What causes sea fog? • In which season is itmost frequent? • Will there be wind? • What makes it clear? It occurs when warm air flows overa cold sea surface (advection flow). Spring / early summer whenthe sea is still cold. Yes A change in wind directionor sea temperature Yachtmaster Meteorology

16. Land Fog It occurs when land cools overnight by radiation of heat. The air cools and moisture condenses to form fog. • What causes land fog? • In which season is it mostfrequent? • Will there be wind? • What makes it clear? Late Autumn / Winter when pressure is high and thereis no cloud. No. Land fog can form in valleys and drift out to sea. The heat of the sun thefollowing morning. Yachtmaster Meteorology

17. Land wind Sea wind Gradient wind Sea wind Land wind Coastal Winds With the gradient wind as shown, what will the wind be on the coast lines? Winds diverge. Coastal wind is weaker Winds converge. Coastal wind is stronger Yachtmaster Meteorology

18. Depression PASSAGE OF A DEPRESSION Cirrus Cold Front Cirrocumulus WarmSector Cirrostratus Cumulonimbus Altocumulus Altostratus Cold Air Warm Air Nimbostratus Warm Front Fractostratus Cumulus 20,000 ft Stratocumulus Cumulus Cool Air East West 200 M 600 M 300 M

19. A Variable, light B L L L NW, strong H Deep depression L SW, light SSE, strong Pressure Systems What is the likely wind at A, B, C ? D H C Yachtmaster Meteorology

20. 976 968 984 960 1000 992 Warm front Cold front Warmsector END Yachtmaster Meteorology