RNLI and Irish Coast Guard volunteers: the wind call, at your height

As a Station Coxswain or Coast Guard unit officer, your daily calls are not about deploying equipment, but about maintaining awareness of conditions. This daily check ensures your crew is ready, whether for routine training exercises or to pre-position resources ahead of an expected change in weather.

Knowing the wind conditions helps you decide if a training session can proceed as planned, or if you need to adjust timings or locations. It also informs decisions about where to position assets, anticipating where they might be needed most.

A wrong call, in this context, does not carry a financial cost, but it can affect operational readiness or crew training. Misjudging conditions might mean a planned training session is unsuitable, requiring rescheduling and impacting crew proficiency. It can also mean that resources are not optimally placed when a real call for assistance comes in.

Your awareness helps ensure that when the call comes, your team is prepared and positioned to respond effectively. The goal is to avoid unnecessary exposure to adverse conditions during training, while always being ready for actual incidents.

For marine operations, the wind at 10 metres above the surface is often the most relevant measurement. This height is commonly cited as a standard for surface wind observations and is directly applicable to vessels operating in coastal waters or open seas. The instrument shows wind at 10, 80, 120, and 180 metres, interpolated to your working height.

Gusts are also critical. While the mean wind speed gives an overall picture, gusts represent sudden, short-duration increases in wind speed that can significantly affect vessel stability and handling. The instrument displays gusts alongside the mean wind speed, providing a more complete picture of the wind environment.

Your operational limit for wind speed is not a fixed, published value, but one you set based on your experience, your vessel's capabilities, and the specific conditions of your operating area. This limit might change depending on the nature of the training, the crew's experience, or the urgency of a pre-positioning task.

This limit, which you input into the instrument, acts as your personal threshold. The instrument uses this value to compute the odds of exceeding it. For heights below 10 metres, the instrument extrapolates below the lowest model level and badges these readings to indicate the extrapolation.

The instrument provides the odds, or P(above your limit), by the hour. This is computed from ensemble members at 10, 80, 100, and 120 metres, showing the fraction of these members that exceed your set wind limit. It is not a calibrated certainty, but rather an indication of how many different model scenarios predict conditions above your threshold.

The Agreement Spine shows where the various weather models agree on the forecast and, crucially, where they do not. When models show high agreement, the forecast is generally more reliable. When there is less agreement, it indicates higher uncertainty, and you may need to exercise more caution.

For example, if the odds of exceeding your limit are around 20 per cent, you might proceed with training as planned, but with increased vigilance. If the odds rise to 50 per cent, you might consider adjusting the training location or delaying it, to avoid unnecessary risks. At 80 per cent, you would likely postpone or cancel the activity, as the probability of encountering challenging conditions is high.

These percentages are examples, and your response will always depend on your judgement, the specific circumstances, and your unit's standard operating procedures. The instrument provides information to support your decision-making, not to make the decision for you.

This is an example of how you might use the instrument during a typical day:

• 07:00: You check the forecast for the day. The wind at 10 metres is forecast at 15 knots for the morning, rising to 20 knots by afternoon. Your training limit is set at 25 knots. The odds of exceeding this limit are low, around 10 per cent, for the morning.
• 09:00: A training exercise is scheduled. With the forecast showing favourable conditions and low odds of exceeding your limit, you give the go-ahead for the exercise to proceed. You note the Agreement Spine shows good model consensus.
• 13:00: You re-check the forecast for the afternoon. The wind is now predicted to reach 22 knots, with gusts up to 28 knots. The odds of exceeding your 25-knot limit have increased to 40 per cent for the late afternoon. You notice the Agreement Spine showing some divergence among models for the evening.
• 15:00: Based on the updated forecast and the increased odds, you decide to conclude the training exercise an hour earlier than planned. This allows the crew to return before the wind strengthens further.
• 18:00: As the evening approaches, you check the forecast for tomorrow. Winds are expected to be calmer, allowing for a planned maintenance session on the water. You make a mental note to check again in the morning.

Your operational limit for wind speed is a critical input for the instrument. This limit is not a universal standard, but rather a value you determine based on your own unit's guidelines, the capabilities of your equipment, and your personal experience as a Station Coxswain or unit officer. The instrument's default setting for marine use is 10 metres height and wind in knots, aligning with common marine practice.

To set your limit, you will refer to your unit's internal documents, training manuals, or standard operating procedures. These documents often outline conditions under which certain activities, such as specific training drills or pre-positioning manoeuvres, should not be undertaken.

Once you have identified this limit from your document, you type it directly into the instrument. This allows the instrument to calculate the P(above your limit) hourly, giving you a personalised risk assessment for your specific operations. For example, if your document suggests that certain training should not occur above 25 knots, you would enter '25' as your limit.

This personalised approach ensures that the information provided by the instrument is directly relevant to your decision-making process, helping you to maintain operational readiness while managing the risks associated with adverse weather.

The instrument maintains a dated record page of what was forecast, what was observed, the limit you used, and the call you made. This record is a valuable tool for review and training, allowing you to reflect on past decisions and compare them with actual conditions.

While formal audits are not typically part of your daily routine, having a clear record supports internal reviews and discussions. It allows you to demonstrate how decisions were made, particularly when conditions were challenging or when a training schedule needed to be adjusted due to weather.

For your own purposes, this record helps you to build experience and refine your judgement. By comparing past forecasts with observations, you can better understand the nuances of local weather patterns and how they impact your operations. This continuous learning is vital for enhancing your ability to make informed decisions in the future.

Furthermore, if there are ever questions about why a particular training session was modified or cancelled, the record provides an objective account of the information available at the time. It serves as a transparent log of your decision-making process, reinforcing accountability and best practice within your unit.

Ireland's coastal environment, particularly its Atlantic exposure, means that wind conditions can change rapidly and significantly. The storm season, generally from October to March, brings higher probabilities of strong winds and challenging sea states, which directly impact training schedules and operational readiness for volunteer units. These seasonal variations necessitate careful planning and constant monitoring of conditions.

Met Éireann, as the national forecaster, provides essential meteorological information, but local conditions can vary significantly even within short distances. The instrument provides a focused view of wind at specific heights, which complements broader national forecasts by offering detailed, localised data relevant to your immediate operational area. This granular detail helps you make more precise decisions for your specific location.

During the summer months, while overall conditions may be calmer, this period often sees an increase in marine activity, which can lead to a peak in launches. Understanding the wind conditions during these busy periods is crucial for managing volunteer resources and ensuring that crews are adequately prepared for potential call-outs. The instrument assists in anticipating these demands by providing hourly wind forecasts, allowing for proactive planning of training and resource allocation.