Transcript weather_test_online_rya

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Skysail
Click on www.skysailtraining.co.uk
Training
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
© SKYSAILTRAINING 2012
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© K M Bater 2012
Skysail
SKYSAIL SKILLS CHARTS
Training
http://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
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© K M Bater 2012
Skysail
Before the Meteorology tests
Training
• Here is the full weather presentation if
you need it (2MB):
http://www.btinternet.com/~keith.bater/weather_for_yachtmast
er_day_skipper_course.pdf
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© K M Bater 2012
Skysail
Forecasts
Training
Where would you find weather forecasts?
On land
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TV
National radio
Local radio
Newspapers
Teletext
Web
Barometer
Mobile phone
At sea
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BBC radio
Coastguard VHF
Metfax to PC
Navtex
Barometer
Observation
Mobile phone
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Day Skipper Weather
© K M Bater 2012
Skysail
Forecasts
Training
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
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Day Skipper Weather
© K M Bater 2012
Skysail
Shipping Forecast Terms
Training
What do the following mean?
Imminent
Soon
Later
Within 6 hours
6 to 12 hours
After 12 hours
of the time of issue of
the forecast
Very poor < 1000 metres visibility
Moderate 2 - 5 Miles
Wave height m
Moderate 1.25 – 2.5
Good
> 5 Miles
Rough
Fair
No precipitation
Poor
< 2 Miles
2.5 – 4.0
Very rough 4.0 – 6.0
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Day Skipper Weather
© K M Bater 2012
Skysail
Wave height
Training
What factors affect wave height?
1
Wind speed and duration
2
Tide speed and direction
wind against tide gives higher waves
3
Depth of water
4
Fetch - the distance over which the wind blows
5
Swell - the wave pattern before the current weather
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Day Skipper Weather
© K M Bater 2012
Skysail
Wind
Training
How do you define the following?
Direction
Direction from which wind blows
Cyclonic
Rapid changes in wind direction
(Possibly at the centre of a depression)
Veering
Changing direction clockwise
Backing
Changing direction anticlockwise
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Day Skipper Weather
© K M Bater 2012
Skysail
Pressure / Wind / Waves
Training
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.
Force 5 17-21 knots
b) Sea heaps up, spray, breaking waves, foam
blows in streaks.
Force 7 28-33 knots
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Day Skipper Weather
© K M Bater 2012
Skysail
Fronts / Buys Ballot
Training
Occluded
Front
How do you define
the following?
Advancing
cold air
Cool air
Warm
Front
Cold Front
Warm air
Occluded Front
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
Buys Ballot’s Law 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.
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Day Skipper Weather
© K M Bater 2012
Skysail
Depressions
Training
What is the weather and wind at A, B, C, D?
D
Light Rain
Wind backs
H
Fair
Light winds
L
Clear, bright
Showers
Good visibility
Wind veers and
increases
C
Day Skipper Weather
Cumulonimbus
Heavy rain
Thunder Lightning
Squalls
B
A
Heavy rain
Poor visibility
Wind increases
Broken cloud
Showers
Very poor visibility
Wind steady
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© K M Bater 2012
Skysail
Depressions
Training
What is the weather at A, B, C, D, E, F, H?
A
Fair
Light winds
Cirrus, fair
Cirrostratus
H
L
Clear, bright.
Cumulus Showers
Good visibility
except in showers.
Wind veers sharply
and increases.
Pressure rises
F
Cold
front
E
Yachtmaster Meteorology
Cumulonimbus
Heavy rain
Lightning Thunder
Squalls
B
C
D
Altostratus
Light Rain
Wind backs
Pressure falls
Nimbostratus
Heavy rain
Poor visibility
Wind increases
Broken cloud
Alto cumulus
Showers
Very poor visibility
Wind veers, steady
Pressure is steady
Warm
sector
Warm
front
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© K M Bater 2012
Skysail
Clouds
Training
What type of clouds and
what do they signify?
Cirrus - can indicate an approaching
depression
Cumulonimbus - thundercloud,
squally, lightning. Cold front.
Cumulus - fair weather
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Yachtmaster Meteorology
© K M Bater 2012
Skysail
Sea Breezes
Training
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.
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Yachtmaster Meteorology
© K M Bater 2012
Skysail
Sea Fog
1.What
causes sea fog?
2.In
which season is it
most frequent?
3.Will
there be wind?
4.What
Training
It occurs when warm air flows over
a cold sea surface (advection flow).
Spring / early summer when
the sea is still cold.
Yes
makes it clear? A change in wind direction
or sea temperature
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Yachtmaster Meteorology
© K M Bater 2012
Skysail
Land Fog
1.What
causes land fog?
2.In
which season is it most
frequent?
3.Will
there be wind?
4.What
makes it clear?
Training
It occurs when land cools
overnight by radiation of heat.
The air cools and moisture
condenses to form fog.
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.
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Yachtmaster Meteorology
© K M Bater 2012
Skysail
Coastal Winds
Training
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
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Yachtmaster Meteorology
© K M Bater 2012
Skysail
Depression
Training
PASSAGE OF A DEPRESSION
Cirrocumulus
Cumulonimbus
Warm
Sector
Altocumulus
Cold Air
Warm Air
Cirrus
Cirrostratus
Altostratus
Nimbostratus
Fractostratus
Stratocumulus
Cumulus
Cumulus
20,000 ft
Cold Front
Cool Air
East
West
200 M
300 M
600 M
WIND
Strong gusts
Veering sharply
Squalls
Steady
Veering
Backing & increasing
PRESSURE
Rising, then
steady
Rising quickly
Steady
Steady
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
Warm
Rising
WIND
PRESSURE
RAIN
VISIBILITY
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TEMP
© K M Bater 2012
Skysail
Pressure Systems
Training
What is the likely wind at A, B, C ?
A
Variable, light
L
L
B
L
NW, strong
H
Deep depression
L
SW, light
C
SSE, strong
Yachtmaster Meteorology
D
H
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Skysail
Training
END
Warm front
Cold front
Yachtmaster Meteorology
Warm
sector
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© K M Bater 2012