uk es it fr pt nl
Birsay Bay Voti
Qualità su una buona giornata: 4.0
Coerenza del surf: 3.0
Folle: 4.0

Overall: 4.2

Vedi tutti i 18 voti

basato su 1 vote. Voto


Surf Report Feed

Birsay Bay Swell Statistics, Spring: All Swell – Any Wind

This image shows the variation of swells directed at Birsay Bay through an average northern hemisphere spring, based on 8682 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the optimum grid node based on what we know about Birsay Bay. In this particular case the best grid node is 17 km away (11 miles).

The rose diagram shows the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but without direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These occurred only 23% of the time. Green and yellow represent increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how commonly that size swell occurs.

The diagram implies that the prevailing swell direction, shown by the largest spokes, was WNW, whereas the the prevailing wind blows from the SW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Birsay Bay and out to sea. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are surfable at Birsay Bay, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical northern hemisphere spring, swells large enough to cause good for surfing waves at Birsay Bay run for about 77% of the time.

IMPORTANT: Beta version feature! Swell heights are open water values from NWW3. There is no attempt to model near-shore effects. Coastal wave heights will generally be less, especially if the break does not have unobstructed exposure to the open ocean.