Forecasting

Most weather and swell conditions can appear random, though with a good eye, regular patterns can be predicted, In much the same way as you would watch the sea for sets of waves. Most surfers no when there will be a good swell at there favorite surf spot.

Watching weather charts will give you up-to-date information and with practice you can even predict the coming swells. The Lines on a weather chart are known as isobars and represent areas of equal pressure. Air pressure is measured in millibars (mb). The lower the air pressure and the closer the isobars are on a weather map, the faster the winds will rotate and bigger the swell will get, resulting in larger waves. Lows in the Atlantic have been known to go down to around 900mb (that's pretty low). Swell comes of at similar angles to the orientation of the isobar lines, and can travel 300 to 400 km in a day. The duration of a swell is related to the speed with which a low travels past a particular swell window, and unlike highs, lows tend to move that much quicker.

The Atlantic Lows can appear anywhere in the North Atlantic, typically deepening as they pass north and eastwards. In summer lows tend to skirt high above the UK, often developing over Greenland and then tracking north east. Winter on the hand is a whole different story, when the oceans all come alive with the lows, which roar over Western Europe from all directions. A low that deepens just north of the Azores will produce good surf for the Canary Islands and south west France. On the other hand, a low that's sitting right next to Ireland will produce classic surf for the north of Spain, yet Ireland itself will probably be huge and blow out. England and Wales have a problem with the swell cast by Ireland, thus a low that sits west of Land's End.

The North Sea Winter is the period of violent weather in this narrow, shallow sea. Deep lows are a regular part of the weather news and swell is highly consistent. A good North Sea summer scenario occurs when the Atlantic fills with a huge high called a blocking anticyclone. These may stay for weeks on end, forcing lows towards Scandinavia. This results in a squeeze of isobars running north to south, sending classic surf to the East Coast of the UK, Norway, Holland and other North Sea spots. The north shore of Scotland may also crank, but could be blighted by on shore winds. A winter low forming around the English Channel will also produce surf from Norway to Belgium, but the swells tend to appear, then quickly disappear as the wind swings. Occasional winter gales can bring cold east or north east winds from the continent, which can bring seizable surf for the UK.