Understanding High-Res Wind Models

As surfers, we know that the quality of waves can be influenced by a variety of factors. One could argue that local winds are probably the most critical element in determining how good or bad the surf will be.

Both wind speed and direction can have a significant impact on surf conditions. Onshore winds are typically unwelcome within the surfing community, especially once they start blowing over 7kts. We generally favor offshore winds, however if this reaches above 20kts it can knock down the surf and make it difficult to paddle into. Even side shore winds (within 20 degrees on either side parallel to the coast) can be just as bad or sometimes worse than onshore winds.

When it comes to predicting the surf, winds play a very important role to us forecasters. Actually, without access to wind models and observations, it would be very hard to forecast the surf at all. Analyzing a local wind forecast can help us determine how conditions will pan out during a swell event.

There are many different types of models available to forecasters. Global numerical weather models use mathematical equations and take large-scale factors, such as the ocean and the dynamics of the atmosphere, into consideration. These models are able to output predictions for hundreds of meteorological elements, for instance temperature and precipitation, using current weather observations as the input.

High-resolution modeling helps to narrow down both the forecast area (spatial resolution) and how often the model calculation occurs (temporal resolution). This is helpful with small-scale phenomena that may impact local winds. For example, a global model may use a 60km spatial grid, while a high-res model may have a 1km spatial grid. As surf forecasters, we often utilize these smaller grid high-resolution models to help fine tune the details of a particular forecast. This is where Surfline’s high-resolution wind models can come in handy.

The high-resolution wind models on our site provide a map of a specified location with wind barbs that display wind direction and speed. The wind barbs point to the direction where the wind is coming from, and the wind speeds are in knots (see the legend below the charts for details on exactly how to read wind barbs). The models are run at various spatial resolutions based on local needs. Again, this is useful with small-scale phenomena such as local sea breezes, mountainous terrain, and temperature differences near the coast. Where we think it’s appropriate, we also use the high-res wind models to drive the winds on the forecast dashboards.

Some of the high-res wind models on the site are run by the NAM (North American Mesoscale Model) developed by NOAA, which has often been found to perform better than global models. You’ll notice that any high-res wind chart driven by this model will explicitly say ‘NAM’ next to the chart. However, Surfline has also developed our own network of high-res atmospheric wind models that provide hourly forecasts, with some models running all the way down to 1km spatial resolution. These charts are available in many places where local winds can often make or break a surf session.

Surfline is happy to share these helpful high-res wind charts with our users. These charts are available in select locations and can be accessed from the forecast pages under the Charts tab. If we don’t have hi-res winds available in your area yet, let us know and we’ll see what we can do!

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