HOW TO INTERPRET THE WAVE FORECAST
You have started surfing, you have your equipment, you feel like it, you know where to go, but something is missing. The when!. Here we give you some tips for beginners on how to interpret a wave forecast, also known as a "Surf forecast" or part of waves.
Although you have often read or heard us say that you ALWAYS have to enter the water even if the wave conditions are not the best, it is very pleasant to be able to arrive at the right place at the right time according to the conditions indicated by the wave forecast. It is a great satisfaction to have the ability to read and interpret those numbers and determine where and when there would be conditions that suit your level of surfing.
I once heard the phrase: "The better the quality of the waves, the better the quality of the surfer", I don't think it's 100% true but it doesn't seem illogical to me at all. So this is one more reason to go in search of that clean and strong wave that can facilitate and allow you to reach the full potential of your surfing.
This is a simple guide on how to interpret the wave forecast data available on the internet.
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First of all, what is the most accurate website? and/or easier to read?
First of all, an important fact to know is that practically all forecasting websites take their data from the same source. They are all centralized departments that in turn obtain their information based on measurements from buoys installed at different latitudes of the world's oceans that send information in real time via satellite to these offices. The big difference between one website and another is in how that information is displayed. The graphical interface (how beautiful the site is), and the weighting that the website makes of that data according to a certain beach, taking into account or not the geography, topography and spatial orientation of the beach, are the factors that may vary from one website to another.
In our experience, the most accurate wave forecast website is Windguru®, a classic, simple and quite reliable website. While it is true that there are many other sites with a better graphical interface, Windguru, with a simple scheme and no display of media, tells you what you need to know to interpret the forecast.
To start with, a little summary of the science of waves.
How are the waves formed?
WAVES – SWELL.
Waves are generated by wind blowing across the sea surface, generating a surface wave that travels across the ocean in the same direction as the gust of wind that generated it. The longer, stronger and farther the wind blows, the greater the disturbances and we will see higher quality waves, stronger and larger on the coast.
These waves or trains of waves that move are called SWELL in English and oleaje or mar in Spanish. For practical purposes in this guide we will use the English word Swell.
Normally these disturbances occur thousands of kilometers away from the coast and move quickly, gaining strength until they reach the coast. These real trains collide with the coast from a specific direction according to the place where it was originally generated (direction of the Swell). Swells can come from any direction, but depending on the geographical area it will be more common for them to come from one direction or another.
IMPORTANT: The name of the direction of the wind and the swell is given by the direction from which they come, and not where they are going. Example: a SW swell is a swell that comes from the South-West.
WIND.
The wind that generates large swells offshore is usually caused by large air masses that move between the hemispheres of the earth. They are usually global, cyclical winds and normally depend a lot on the seasons of the year, rotation of the earth, etc.
The wind also exists on the coast. This wind, called local wind, generally blows for a short time and, like large offshore winds, generates disturbances on the sea surface and WAVES. These waves generated by local wind that have traveled a short distance are generally of poor quality, small, disorderly and without force.
The local wind plays a VERY IMPORTANT factor, since it can damage or favor the wave that comes from offshore, traveling for thousands of kilometers. When a large and strong swell enters the bay and generates waves that face a wind that hits it head-on against its wall (OFFSHORE wind), this wave slightly reduces its travel speed, becomes more cylindrical and of much better quality. for surfing. On the contrary, if the local wind is ONSHORE (from the sea to the beach), the wind hits the wave "from behind", causing the wave to close, disorder and worsen surf conditions.
WAVE PERIOD. (important).
The wind that generates the swell at its origin blows intermittently like a beating heart. These pulses are translated into synchronously separated waves, which is called SWELL PERIOD, or also called “distance between waves”. This period determines the strength of the wave and how clean it will reach the shore. The SWELL period can range from 1 to 25 seconds (or more). For example, a period of 15s means that approximately every 15 seconds a wave will enter the bay. Of course, this is not exact as there are local wind, tidal and current conditions that affect the conditions and period of the SWELL.
The swell period is one of the most important factors in reading wave forecasts. Swells with long periods are more powerful and are less affected by local winds. A period of 15 s or more is a true freight train that, with the right direction, almost certainly guarantees good waves on your beach.
Before going to the reading, it is important to emphasize the difference between LOCAL CONDITIONS, what happens on your beach, at this moment, and GENERAL CONDITIONS, what happened several days ago thousands of kilometers away and that has been traveling until "hit ” with the coast.
In summary: There are two main factors in the wave forecast equation:
1. SWELL. Size – direction – period of the swell.
2. WIND. Direction – Wind speed.
TIPS TO INTERPRET THE WAVE FORECAST:
– Rule of thumb, swell period greater than 15 seconds, surely there will be a good surf, orderly and strong, regardless of the reading of the size on your beach. You just have to find the right beach for that size.
– The size of the wave is usually overestimated in forecasts. Because the size is measured in offshore buoys and considers the biggest wave in the set. Upon reaching the coast, this size is reduced in its interaction with the seabed. That is why normally, to correctly interpret the wave forecast, you must subtract at least half a meter from what the forecast indicates in relation to the size of the wave at sea.
– In this equation, the wind is by far the most difficult to forecast. It changes so easily that the forecast may show a certain direction, and when you get there it may be blowing exactly the opposite way.
– Golden rule for the wind: The times of the day when there is less wind are at dawn or very early in the morning and at sunset. This is because the local wind is produced by the difference in temperature between the sea and the land and at these two times of the day is when the land is almost the same as the sea temperature, so there is no flow of air masses. .
– TIDE also affects the quality of the wave. This is a constant and cyclical factor that is independent of climatic factors, since it is given by the effect of the attraction of the moon's gravity on the masses of water on earth. The tides can be known in tide tables or in some wave forecasting websites such as magicseaweed® or Surfline®. There are high, medium and low tides (which have no relation to the size of the waves!). Some beaches, normally beachbreaks, are highly favored by high tides, while point waves or irregular bottoms benefit from medium or even low tides. Find out with experienced surfers what is the best tide for your beach.
INTERPRET WAVE FORECAST
Let's review this example from La Boca Beach in Concón (Chile).
In the image of @LaBocaSurfcam, we can see a Saturday around 8:30 am. Very good quality of waves for beginners and intermediates. 1,5 meters of real wave, clean (glassy), orderly and breaking long and slow to the shore. A real playground!
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What the wave forecast in Windguru® indicated for that day:
– Wind speed: 3 knots (white box). Virtually no wind.
– Wind direction: South-west.
– Wave (swell size): 2,1 meters.
– Period: 14 seconds (red boxes).
– Direction of the waves (swell direction): South-west.
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We know that this beach (one of the most popular in Chile), due to its orientation, benefits from south-west swells (predominant on the Chilean coasts), with periods of over 14 seconds, a soft southerly or easterly wind (from land) and rising or high tide. On the other hand, north swells with wind from the same direction and low tide are usually the worst combination for surfing in Concón.
In general terms, to sharpen your eye and interpret the wave forecast quickly, keep the following in mind:
- WIND SPEED: always look for “white boxes”, light winds of less than 5 knots. Midday is normally the time of day with the highest local wind, which means bad surf. On the contrary, very early in the morning and at sunset, the wind practically stops blowing.
– BURST: Data that is not relevant for the interpretation of the wave forecast for surfers.
- DIRECTION OF THE WIND: The direction from which the wind blows. Look for OFFSHORE winds (from the beach) or side winds. Ideal are the days without wind, where the sea looks like a mirror of water, also called glassy or icing.
– WAVE (swell size): Indicates the size of the largest wave of the set in meters when passing through the buoy. It is usually an overrated number. For example, if it indicates 2 meters, consider waves on average of 1 to 1,5 meters on the set.
– WAVE PERIOD (swell period): Short swell periods indicate rough seas and disorderly surf with small, weak waves. On the contrary, periods of more than 15 s, assure you a session of strong and orderly waves entering the bay clean (if the local wind allows it).
– WAVE DIRECTION (swell direction): Each beach has its ideal direction or angle from which the swell enters and generates good wave conditions. Consult with the locals of your beach to find out which direction of the swell benefits your spot.
HOW CAN I KNOW THE WIND AND SWELL DIRECTION BY LOOKING AT THE ARROWS ON THE SCREEN?
Let's imagine that you are looking at the wave report directly on your computer screen. In this case, NORTH will always be at the top of the screen, SOUTH will always be at the bottom, WEST will be on your left, and EAST will be on your right. Considering these reference points we will be able to interpret where the arrows point.
Example:
In the wave forecast image, on SATURDAY 7, at 6:XNUMX a.m. We have a wind direction with an arrow that points up and to the right of the screen (towards the north-east), that is, the wind travels from the south-west (towards where the tail of the arrow points). IMPORTANT: The wind is denominated according to the direction from which it originates and NOT where the arrow points. In this case the wind is – SOUTH-EAST-.
This can be quite confusing when interpreting the wave forecast, especially if we go by the arrowhead, but if you think about it taking into account the origin of the wind it becomes a little easier. Other important information to make interpretation even easier, is that if you place your mouse cursor just over the forecast arrow, the website indicates the wind direction as follows: SW (south-east), SSO (south - southwest) , NO (north-west), etc.
If you are interested in the subject and want to become an expert wave forecaster and impress your friends, we recommend the book “Surf Science” by Tony Butt. Excellent reading material, easy and entertaining.
Now that you know some of the science of surfing, how the wave is generated and how to read the surf report, all that remains is to know what the ideal conditions are for your favorite beach.
How can I know?
1- Asking more experienced surfers what conditions are optimal for your beach and its surroundings.
2- Trial and error: check the forecast before going, write it down and when you're on the beach analyze the session, was it good, bad, fair? Record the conditions that occurred in good and bad sessions and little by little you will make your own record wave weather.
With patience, perseverance and good waves, you will be able not only to know how to interpret the wave forecast, but also to be a great surfer!
With love for Wolf, for Flysurf.
#SurfBetterNow
