The
number one rule of any sailor is to check the weather before one goes
out. Remember too much wind can be very dangerous with the risk of
capsizing in high seas and drowning. Too little on a hot day can be
miserable but also hazardous predisposing to dehydration and
hyperthermia. Checking the weather should also entail checking the water
conditions, including tide information, wave height and temperature. A
marine forecast in your local area should always be checked.
Local TV, cable stations, National Weather Service (VHF Radio Channels W1
to W4) and the internet are good resources. The Weather Channel's website
also has marine forecasts including water temperature and wave height.
View Website
The National Weather Service has two useful websites one for the local
forecast
View Website
and the other for marine weather forecast
View Website
The weather over the water may not correspond to that at your home. On
small inland lakes and waterways the weather tends to be fairly constant
in a region. However, in coastal areas the weather may vary significantly
between land and sea.
The
picture on the right shows large thunderheads as one looks out to sea
across the barrier islands. You never want to be caught in a thunderstorm
and it may be a good idea to stay home if the forecast calls for
thunderstorms. However, this picture was taken in Florida and
thunderstorms happen frequently – if the conditions are right, they can
occur almost on a daily basis. In this case, the decision to go sailing
will depend upon the understanding of land and sea breezes and the time of
day. A land breeze blows from land out to sea and is created as the
warmer-lighter air above the water rises, drawing in the cooler, heaver morning
air over the land. As the land heats up with the daytime sun the air
becomes lighter and starts to rise. A sea breeze is created which
changes the direction of the wind and the wind starts to blow from the sea
to the land. This change usually occurs slowly between 12:00 noon
and 3:00 pm resulting in a time of very little wind in the early
afternoon. ( If you want to go sailing, early morning
or later afternoon would be the preferable times. ) If the above picture
was taken at 7:00 am in the morning, you may want to go sailing since you
will have a land breeze to hold these clouds offshore. If it was taken at
1:00 pm in the afternoon, watch out, since a sea breeze will form which
may bring the storm ashore. All this being said, you must always check
the weather, since large frontal systems can easily overcome the effects
of land and sea breezes.
In other areas, the weather forecast can be of marginal value. In the San
Juan Islands in Washington State, the weather changes markedly between the
mountainous islands as they channel wind and weather between them. A
sailor could be sitting for hours in a windless pocket of air while
listening to gale warnings a few miles away on the other side of the
islands. A similar situation may exist when sailing on inland rivers
where winds can be channeled up or down the river valley.
(Note: Winds are described as where they blow from. Currents are
described as where they flow to. Thus, a northerly wind blows from the
north. A northerly current flows toward the north.)
Prediction of future weather can be done by
using a barometer and noting the types of clouds in the sky. If the
barometric pressure falls, it indicates a low pressure system, or a front,
is approaching which can cause bad weather conditions with high winds,
reduced visibility in fog or rain, and lightening storms. A rising
barometer forecasts good weather. The faster the barometer changes the
more dramatic the weather. Cirrus clouds or "Mare's tails" are thin wisps
of high altitude clouds-see above picture. When followed by cirrostratus
(high gauzy sheets) deteriorating weather may be approaching in 24 to 48
hours.
