About This Station
The Ravenspoint station uses a Davis Vantage Pro 2 weather station. Its anemometer, rain gauge and temperature and humidity sensors provide the local observations shown on this site. WeeWX collects and archives the readings, and normally refreshes the public station pages every five minutes.
How the Ravenspoint forecast works
The short-range wind forecast is a separate, experimental system designed for the unusually local conditions around Ravenspoint and Trearddur Bay. It produces forecasts for each of the next six hours and normally runs every fifteen minutes.
- Observe: a fresh copy of the Davis station archive supplies the latest wind, gust, direction, pressure, temperature, humidity, rain and solar patterns.
- Add wider guidance: the system collects Met Office site-specific and probabilistic forecasts, nearby observations and other supporting weather information. Marine wave guidance and tide information are added by the sailing tools where relevant.
- Build several candidates: it compares a locally trained forecast, locally corrected Met Office guidance, recent-wind persistence and a model based on historical differences between official forecasts and conditions measured at Ravenspoint.
- Select safely: recent accuracy is scored separately for each forecast horizon. Sources performing materially worse can be excluded, while data-quality checks force a fallback to established Met Office guidance when local station inputs are incomplete or implausible.
- Check every forecast: each modelled forecast is retained until its target time, then compared with the observation subsequently recorded by the Davis station. Wind, gust and direction errors are scored for each of the six forecast horizons. Those verified outcomes update source scoring, local bias corrections, direction-sector calibration, likely ranges and gust-risk estimates.
- Publish once: one timestamped six-hour forecast is sent to the website. All tools reading it therefore use the same wind, gust, direction, uncertainty and sailing-suitability values.
How the model is allowed to improve
The live production model is not automatically replaced merely because a newly trained version is available. Retraining creates a separate candidate model using the historical observation databases. Testing follows time order: the candidate learns from older records and is scored on later records that were held back from that training, using two rolling historical test periods. Imported historical Met Office UKV forecasts are also matched with the observations that followed them so that locally corrected official guidance can be assessed without using future information.
A candidate normally replaces the production model only when it clears all of the promotion gates: it must provide all six forecast hours, improve the combined wind, gust and direction error by at least 2%, avoid a material regression at any individual hour, beat the simple assumption that the recent wind will continue, and avoid increasing the rate of falsely reassuring “likely suitable” sailing forecasts. If it fails any gate, the existing production model stays in use and the rejection reason is recorded. Experimental specialist models can also run in shadow mode, where they are scored but cannot influence the published forecast until their evidence and safety checks are strong enough.
This creates two complementary checks: the historical databases decide whether a proposed model is good enough to replace the current one, while every new live forecast is checked against the later station reading to confirm how the active forecast and its component sources perform in current conditions.
How the forecast updates the website tools
- Sailing weather summary: turns the latest observation and six hourly forecasts into the headline outlook, timeline and suitable, marginal or unsuitable periods.
- Hourly forecast detail: uses the selected forecast hour for wind, gust risk, uncertainty, direction changes and course guidance, alongside official weather and marine information.
- Local Forecast Model Details: shows the full forecast, source blend, confidence, uncertainty ranges, recent accuracy and comparison with Met Office guidance.
- Race-day Dashboard: matches the forecast nearest the planned start time to the selected fleets and the 2026 Course Selector, then adjusts the recommendation using sea-state guidance and, where available to authorised users, tidal information.
- Course Selector Matrix: supplies the fixed wind-direction and wind-strength rules used by the automated course recommendations; the forecast selects the relevant part of that matrix.
- System status and safety checks: monitor the age, completeness and validity of the station, forecast and supporting feeds. Stale or failed essential data suppresses a reassuring recommendation and prompts the user to check conditions independently.
The site refreshes its displayed values from the latest published files; it does not invent a new forecast for each visitor. A forecast may change at the next fifteen-minute run when newer observations or upstream guidance arrive, or when the system has enough verified outcomes to alter its source weighting.
Important: the local forecast and course suggestions are decision-support tools, not go/no-go instructions. Current observations, official forecasts and warnings, sea state, tide, visibility, local knowledge and the judgement of the sailor or race officer always take precedence.
About Ravenspoint
Ravenspoint, at the southern side of Trearddur Bay on Anglesey, is exposed to rapidly changing coastal wind and weather. That local variability is why the system combines an on-site station with wider forecast guidance and continually checks predictions against what was actually observed.
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