The yachtsman's weather guide

Citation preview

The Yacht

The

Yachtsman’s

WEATHER

GUIDE

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The Yachtsman’s

WEATHER GUIDE Ingrid Holford

Airlife England.

Front

cover:

Moderate,

force 4 wind,

small waves

Copyright © Ingrid Holford First published in Great by Ward Lock Limited.

Britain

becoming

longer,

11-15 knots.

Patrick Roach

1988 in 1979

This second revised edition published by Airlife Publishing Ltd. in 1988. All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical including photocopying, recording or by any information storage and retrieval system, without permission from the Publisher

Printed

in writing.

in England

by Livesey

Ltd.,

Shrewsbury.

Airlife Publishing Ltd. 7 St. John’s Hill, Shrewsbury,

England.

Contents

Preface Introduction

1 Transmission of heat 2 Local winds

Atmospheric pressure Synoptic charts and pressure winds Water vapour in the air Dew, frost and fog, by contact with cold surfaces

Clouds and showers, in thermals

by lift over high ground and

Clouds, rain and snow, by lift in converging winds Isobars around low pressure

Isobars around high pressure 11 Forecasting with modern technology 12 Making your own weather chart Index

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Introduction and Acknowledgements

This book is written for everyone who goes afloat and is at the mercy of the weather. | have stretched the word yacht to include everything from small dinghies to large cruisers, both sailing

vessels and powered craft. I have also used the term yachtsman to include yachtswomen and yachtschildren, so that I may use he and him for everyone, to keep the text easy to read. In this revised edition, I have taken heed of constructive comments made by reviewers 6 years ago, and tried to simplify some of the difficult topics, highlighted for me by sailing instructors and yachtsmen to whom | have lectured. Meteorology is an imprecise science and forecasts are sometimes wrong, but rarely from negligence. The atmosphere is so vast that it cannot be monitored completely, even with satellites and remote self-recording instruments, and weather has an almost human ability to change its mind when a yachtsman is most vulnerable. That is when it is important to know how to make and use a weather chart from the Shipping Bulletin, in order to cope with deteriorating weather which may advance quicker than a yacht can travel.

Forget that much of meteorology is beyond the comprehension of most of us. Simply learn how to use the information provided by the professional, add your own local knowledge and logical reasoning based on the facts in this book, and the

result will be forecasting at its best. I should like to graphs to this book, my own. And my who have been so finished book.

thank those who have contributed photoacknowledged underneath all which are not especial thanks go to Airlife Publishing Ltd successful in converting my ideas into the

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