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, Settembre: All Swell – Any Wind

This picture shows the range of swells directed at Birsay Bay over a normal September. It is based on 2880 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the best 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 lacks 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 15% of the time. Green and yellow illustrate increasing swell sizes and red represents the biggest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell was forecast.

The diagram implies that the most common 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 lump these in with the no surf category of the bar chart. To avoid confusion we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Birsay Bay, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical September, swells large enough to cause surfable waves at Birsay Bay run for about 85% 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.