Wave forecasting - possible?

[Herb Miller]

After reading this thread today, "Heavy weather, can we be honest? ", I have a question. I am new to sailing, so here goes.

Many of the posts mentioned that waves were much more of a problem than wind, and I know of several wind applications that are available.

But, is it possible to forecast what the waves will be? Are there applications for wave prediction? Are there rules of thumb for wave predictions?

I know that NOAA has a buoy database. Is that data just current data, or are there predictions available, also? Anyway, the coverage seems very limited for that database.

Thanks.

[Cheechako]

Most marine forecasts will include the wave heights. They will get you in the ballpark.

[Steadman Uhlich]

I like Windy (free ap online).
I like its interface design and find it easy to visualize and use the large amount of data it presents.

Here is a link.

At the bottom of the page (when viewed with a browser like Safari) there is a tab for "waves" which shows the projected wave height and period and direction,AND the swell height and period.

If you look at this linked page you should see the Wave data chart below the image of the location (Hatteras).

https://www.windy.com/35.246/-75.410...m:eDTad3t,d:we

[Paul Elliott]

Here's a link to a NOAA page that I use: Ocean Prediction Center - Pacific. This is for the Pacific, but they no doubt have other compilation pages. You will notice the "wind and wave" and "wave period & direction" forecasts. You can also get similar wave forecasts via GRIB data.

[Lepke]

If you also learn to read weather maps, over time you should be able to come up with a better local forecast. Often, when commercial fishing, we swore the local guys never opened the window. Our concern was waves. In my day, most fishing boats were wood and coming home alive a priority.

[belizesailor]

Plenty of forecast options for waves. GFS GRIB data includes wave forecasts as do many other models. Also NOAA RadioFAX Wind/Wave Charts. To name just 2.

[travellerw]

We use no less than 4 pieces of reference data (Windy, Passage Weather, Buoy Weather and Gribs, sometimes others). Averaging the wave heights from those resources usually gets us a ROUGH ballpark. You still get the odd, SONOFABITCH, where did that come from wave.

So to answer that question. Yes, you can get a general idea of "the ocean state" from the forcast sites.

[wsmurdoch]

Originally Posted by Paul Elliott

Here's a link to a NOAA page that I use: Ocean Prediction Center - Pacific. This is for the Pacific, but they no doubt have other compilation pages.

For the South West North Atlantic and Caribbean Sea: Gulf and Tropical Atlantic WX Briefing Package

The wave height is with the wind, and direction and period are forecast together.

As well as being on the internet, all this is also available on HF Fax (short wave radio) several times each day with a radio and a computer.

[wannacat]

Predict Wind, Passage Weather and Windfinder Pro all have wave predictions.[height and direction] I use them all the time. Good luck

[Tessellate]

It's certainly possible to forecast waves, and NOAA does it for certain areas. See the marine forecasts on noaa.gov.

In inshore areas that have ocean swell (ex, the western Strait of Juan de Fuca) they describe the height and period. Ex: "W swell 5 ft at 10 seconds. Wind waves 1 - 3 feet."

For inshore areas with no ocean swell, they just forecast wind waves, which are based on the strength of the wind.

It's like describing an apple as red and round. Sure you've correctly named two attributes, but it's a crude and incomplete description of waves.

I started a CF thread related to this a couple years ago:
http://www.cruisersforum.com/forums/...te-151610.html

Probably the hardest part of our learning curve from protected-waters sailors to venturing further, was learning waves. There are still many kinds of waves we haven't seen, and the words to describe waves are inadequate. The forecasting is much more basic than wind/weather forecasting, with much less precision. (we have local weather down to the zip code, but no wave forecast that would tell us the waves will be 1-2 feet here but 3-4 feet at 3 seconds at the tide rip line just around the corner). Nautical charts mark tide rips, but that doesn't mean there will always be a tide rip there. It's much more complex than that.

So mostly it's a matter of experience, learning how to deduce wave patterns on your own and learning about local effects yourself or through other sailors.

[Dockhead]

Yes, as others have said, you can get them on all the wind forecast sites.

I never look at them. You quickly learn what the sea state will be, based on how hard it will be blowing for how long over what kind of fetch, and how to make allowances for depth, land effects, and effects of tide and current.

In the ocean in deep water and far from land, we don't worry about sea state in F8 and below. Near land you pay attention to tidal races and wind against tide. If you are protected by the land, you know the sea state will be much more benign than it would be otherwise.

In any case, in F8 and below, you are not so much interested in wave height, as you are in the SHAPE of the waves, which is determined by their period. Wind against tide makes them much more vicious; wind with tide smooths them out. Smaller bodies of water like Med or Baltic have lower waves for a given wind strength, but shorter period and steeper, so may be actually more difficult than what you find in the ocean.

From F9, all bets are off. Eventually the waves get high enough to form breaking crests, which are really dangerous. I've seen that once in my life, and once was enough.

[Paul Elliott]

I do look at the wave data. In the areas where I sail offshore, the big swells can be coming from a long way off, and it's hard (for me) to know how big they will be based on the distant WX systems. Big swells by themselves aren't usually anything to worry about, but when coupled with local conditions they can be a problem.

[barnakiel]

Yes. Wave forecasts are available and they are as good as wind forecasts.

Play some with zyGrrib or any similar program. They actually download not only wind wave predictions but also swell and secondary swell wavetrains.

Good stuff and very useful.

[Calif.Ted]

The last time I was hit by a gale as described in that thread the forecast was for "5-15 kts. wind with 4 to 6 ft. waves overnight" winds were in excess of 40 and I was looking UP at the waves. So wave or wind when they're wrong, they're wrong and that's when the prudent mariner gets into "unpleasant" conditions.
If you are interested in wave predictions surfline has a lot of material available for coastal areas worldwide.
Jalama to the Ranch Nearshore Chart | SURFLINE.COM

[Steadman Uhlich]

This screenshot shows the amount of data on waves shown on the Windy wave page or tab. Notice the rows for local wind waves and for different swells.
Also notice the small arrow icons which show the wave or swell direction, and that it changes over time.