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CYCC News 17 March 2001

Weather Forecasting - Observations by Jonathan Virden

OBSERVATIONS

Weather information is critical to planning of safe navigation at sea by small ships. It has become very difficult, and sometimes impossible to record shipping forecasts while at sea, or when planning voyages so that the details can be considered fully after the broadcast. The information supplied to the main shipping forecasts is as good and useful as possible with the meteorological technology available today.

It is highly effective in avoiding unwise passages. But the details become degraded or unavailable at the last stage of transmission because the speed of reading is too high...

EXPERIENCE

For more than 30 years I have used the main Long Wave shipping forecasts. This has been the basic source of weather forecasts I use for all sailing trips, including up to 48 hrs away from port in UK/ near European waters. This is especially true when one is inland, without easy access to Marine VHF broadcasts. During the past 2 years I have noticed that it has become more and more difficult ot record the forecast by writing it down. I use a simple short-hand code of two letter groups and numbers, and arrows which is quite quick. BUT either I have slowed very much or the time available for the forecast to be read has become too short for me to record all the details, leaving serious uncertainty about what was broadcast.

DISCUSSION

Weather forecasts are absolutely fundamental to the safety of navigation at Sea. The forecasts have become so good during the past 10 years that anyone going to sea is now much less likely to get into trouble caused by the weather than formerly. The probable sequence of weather is extraordinarily well predicted. The timing of change is less certain, but a bit of knowledge, now commonly available, and basic observation allow the sailor to follow the weather very well, and thus predict what they will meet at sea, whether to leave port at all, or to seek shelter. It seems to me that unless the details of what is heard can be written in some form which is easily studied again, much of the effort of forecasting and broadcasting the forecast is wasted. A most important example is the 5-day forecast on Sunday morning. This has important uses and implications for those who plan going to sea during the following week. (Obvious?) But because the format cannot be standardised (which speeds up the normal shipping forecast and the wording of it) because of the variations which are inherent in such descriptions of future weather in varying patches it is quite often impossible to record such important and detailed information at the speed at which it is read.

TRIAL or CHALLENGE

I would challenge anyone who doubts that the difficulty exists to write down all the details of a set of forecast details for, eg areas Wight, Portland, Plymouth, Biscay, Sole, Fastnet, Lundy, Shannon, Irish Sea for six consecutive forecasts. This would be normal practice for anyone planning a passage from Falmouth to Cork or Dublin. Hundreds of boats do this each year, and each month in the summer. The reader should try too, and for three successive forecasts. A more serious trial would be to have the readers of the forecasts do the same, especially the 5-day forecast on Sunday.

CONCLUSION

If the shipping forecast is to be a useful service, making use of the very good information supplied to it, the speed of reading must be reduced to that at which most users can write down the details. This probably requires that all government departments and agencies concerned with safety at sea buy time from the BBC or come to some arrangement with the corporation to achieve successful reception by mariners of this information critical to safety.

DISCUSSION POINTS

  1. Navtex is wonderful when it works, but the coverage will never be complete in the way achieved by Long Wave without many more transmitters and more powerful transmitters (probably not achievable for regulatory reasons). Last summer Portpatrick was useless. Malin Head was very good. Universal coverage is absolutely required for a safety system.
  2. Tape recording of what is read is only reliably possible with similar expense as Navtex and probably much less reliability at sea. No electronics of that sort can be expected to work for long in the environment of small boats, perhaps especially those who need the forecasts most for safety as they are the most vulnerable to bad weather. Solid state memory might work reliably, but is not here yet.
  3. I suspect that with a bit of rearrangement, after much consultation with those who do and will use the information, it would be quite possible to read what is necessary in the time available now at a writeable speed each using their own simple code. The inshore forecasts contain many redundant words. Eg " the wind" and "visibility" about eight times each.
  4. More complex methods of getting forecast information, eg fax or from internet cost money and need expensive equipment (with doubtful reliability at sea) and so will just be ignored by a great proportion of mariners... I ignore them and will continue to do so.
  5. The weekly long range forecast slightly different; it does not have information normally requiring immediate action. But it can have much influence in helping mariners to avoid avoid getting into a difficult position. Also it probably cannot have a standard format which makes it much more difficult to write down, at speed above dictation speed, which is particularly necessary for imformation which will be used some days later as it only comes weekly.

Shipping forecasts
Year 2000 Jonathan Virden