Re: Weather Forecasting
Someone asked about the book. I havent had success using the method
yet and all the clouds look the same height to me, most of the time,
as you say.
Bernard Moitessier was a very experienced seaman (one of my heroes)
and Alan Watts has published several books on weather and written
several articles in English yachting magazines.
My daughter gave me an Oregon Scientific weather station. It is the
model that shows the barometric pressure as an arrow that points up,
across or down instead of as a graph unfortunately but for landsman
it is surprisingly accurate for forecasting rain. Dave Limbrick
yet and all the clouds look the same height to me, most of the time,
as you say.
Bernard Moitessier was a very experienced seaman (one of my heroes)
and Alan Watts has published several books on weather and written
several articles in English yachting magazines.
My daughter gave me an Oregon Scientific weather station. It is the
model that shows the barometric pressure as an arrow that points up,
across or down instead of as a graph unfortunately but for landsman
it is surprisingly accurate for forecasting rain. Dave Limbrick
--- In bolger@y..., "Nels" <arvent@h...> wrote:
> --- In bolger@y..., "bifino" <davel@n...> wrote:
> > Bernard Moitessier in his book A Sea Vagabond's World says "I
> Hmm... I find this interesting - trying to visualize how one might
> measure the relative speeds and directions of different cloud
layers
The two greatest advances in weather forecasting since it began are
the weather satellites and the computer. For one small example go to
the following:
http://www.intellicast.com/LocalWeather/World/Satellite/World/
Notice the huge frontal system that extends from east of the
Carolinas almost to Great Britain. The northern route looks a bit
more peaceful;-))
the weather satellites and the computer. For one small example go to
the following:
http://www.intellicast.com/LocalWeather/World/Satellite/World/
Notice the huge frontal system that extends from east of the
Carolinas almost to Great Britain. The northern route looks a bit
more peaceful;-))
--- In bolger@y..., "Nels" <arvent@h...> wrote:
> --- In bolger@y..., "bifino" <davel@n...> wrote:
> > Bernard Moitessier in his book A Sea Vagabond's World says "I
> > heartily recommend Alan Watts' little book Instant Weather
> > Forecasting, which taught me how to predict weather changes in
> > minutes.
--- In bolger@y..., "bifino" <davel@n...> wrote:
measure the relative speeds and directions of different cloud layers
while on a pitching moving boat. This is actually very difficult to
do even on dry land since the relative angles from your viewing
location differ with the distance you are away from the clouds. For
example, jet-stream cirrus (which he must be referring to) may be
located at 35 thousand feet and moving along at more than 200 knots,
while low level clouds would be moving at the the same speed as the
surface wind - say 20 knots. (The general height of cumumlus can be
quite easily determined if you know the temperature and dewpoint.
However figuring out the dewpoint is not easy at sea and cumulus are
more common over land!) The low level clouds may appear to the eye to
be moving faster than the cirrus because they are much closer to the
observer. Also observing the lower layer movement may cause one to
believe that higher clouds are moving in the opposite direction
because of this illusion. Also there may be four or maore layers of
cloud at different levels, especially when a front is approaching. Or
there may be no cloud at all, and gail winds blowing.
I have never heard of any crosswind rule in all my years of being
associated with weather analysis. There is one very handy rule that
does apply well at sea where there are no geographical interferences.
If you stand with your back to the wind, the area of lowest pressure
is to your left - when in the northern hemisphere. If you are sailing
in that direction and the pressure is falling and the wind
increasing you are sailing towards the centre of a low pressure
system that gives you the worst weather. If you sail in the opposite
direction and the winds begin to lighten you are sailing towards a
high pressure system and may become becalmed.
This is not really weather forecasting, but merely extrapolating
current conditions, and assuming they will not be changing. Weather
forecasting involves being able to predict how the weather systems
are moving and evolving as well as assessing the current conditions.
Nels
> Bernard Moitessier in his book A Sea Vagabond's World says "Icoloured
> heartily recommend Alan Watts' little book Instant Weather
> Forecasting, which taught me how to predict weather changes in
> minutes. Its terrific, all you do is compare the lower, or surface
> (cumulus) wind direction with the upper, or high altitude (cirrus)
> wind direction and apply the crosswind rule. " There are 24
> photos of clouds and a full explaination of the theory.Hmm... I find this interesting - trying to visualize how one might
> Hope this helps. Dave Limbrick
measure the relative speeds and directions of different cloud layers
while on a pitching moving boat. This is actually very difficult to
do even on dry land since the relative angles from your viewing
location differ with the distance you are away from the clouds. For
example, jet-stream cirrus (which he must be referring to) may be
located at 35 thousand feet and moving along at more than 200 knots,
while low level clouds would be moving at the the same speed as the
surface wind - say 20 knots. (The general height of cumumlus can be
quite easily determined if you know the temperature and dewpoint.
However figuring out the dewpoint is not easy at sea and cumulus are
more common over land!) The low level clouds may appear to the eye to
be moving faster than the cirrus because they are much closer to the
observer. Also observing the lower layer movement may cause one to
believe that higher clouds are moving in the opposite direction
because of this illusion. Also there may be four or maore layers of
cloud at different levels, especially when a front is approaching. Or
there may be no cloud at all, and gail winds blowing.
I have never heard of any crosswind rule in all my years of being
associated with weather analysis. There is one very handy rule that
does apply well at sea where there are no geographical interferences.
If you stand with your back to the wind, the area of lowest pressure
is to your left - when in the northern hemisphere. If you are sailing
in that direction and the pressure is falling and the wind
increasing you are sailing towards the centre of a low pressure
system that gives you the worst weather. If you sail in the opposite
direction and the winds begin to lighten you are sailing towards a
high pressure system and may become becalmed.
This is not really weather forecasting, but merely extrapolating
current conditions, and assuming they will not be changing. Weather
forecasting involves being able to predict how the weather systems
are moving and evolving as well as assessing the current conditions.
Nels
Bernard Moitessier in his book A Sea Vagabond's World says "I
heartily recommend Alan Watts' little book Instant Weather
Forecasting, which taught me how to predict weather changes in
minutes. Its terrific, all you do is compare the lower, or surface
(cumulus) wind direction with the upper, or high altitude (cirrus)
wind direction and apply the crosswind rule. " There are 24 coloured
photos of clouds and a full explaination of the theory.
Hope this helps. Dave Limbrick
heartily recommend Alan Watts' little book Instant Weather
Forecasting, which taught me how to predict weather changes in
minutes. Its terrific, all you do is compare the lower, or surface
(cumulus) wind direction with the upper, or high altitude (cirrus)
wind direction and apply the crosswind rule. " There are 24 coloured
photos of clouds and a full explaination of the theory.
Hope this helps. Dave Limbrick