Birsay Bay Wind Stats

The rose diagram shows how commonly and how strongly the wind blows from different directions through a typical November. The longest spokes point in the directions the wind most commonly blows from and the shade of blue suggests the strength, with dark blue strongest. It is based on 3347 NWW3 forecasts of wind since since 2006, at 3hr intervals, for the closest NWW3 model node to Birsay Bay, located 17 km away (11 miles). There are not enough recording stations world wide to use actual wind data. No doubt some coastal places have very localized wind effects that would not be predicted by NWW3. According to the model, the most common wind at Birsay Bay blows from the WNW. If the rose graph shows a fairly circular pattern, it means there is no strong bias in wind direction at Birsay Bay. By contrast, dominant spokes illustrate favoured directions, and the more dark blue, the stronger the wind. Spokes point in the direction the wind blows from. Over an average November, the model suggests that winds are light enough for the sea to be glassy (light blue) about 1.8% of the time (1 days each November) and blows offshore just 27% of the time (8 days in an average November). In a typical November winds stronger than >40kph (25mph) are expected on 10 days at Birsay Bay

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