If find the wind predictions from Swell Info to be fairly accurate, but like any weather prediction, its about knowing your spot, putting your own eyes on it. Far to often the surf sucks or gets ridiculously good when quite the opposite is being predicted. I also find the local news to be a good place to check for wind predictions.
As to your query about where the predictions come from, everyone is right, different surf prediction services use different weather services and even buoys or local weather stations. I say again, why not just go look at the surf. If you are not in such a position, local surf shops have call-in reports, you can view cams, or you can use marine forecasts when making a decision to drive to the surf. Still, there is no better surf forecast for a given day in question then your own two eyes. Everything else is just a tool to give a general idea of what might happen, and they are all wrong often enough to never completely trust.
Equally, when the wind is blowing and the swell is right, its about knowing your local surf zone and multiple spots. No swell forecast service can beat this most useful of predictors.
Yes, local knowledge is key. I know of spots with condos in the right configuration that deflect the onshores at the right angle and speed. Not even the tides are totally predictable, due to the effect of winds, currents and other variables. The uncertainty makes the really good sessions just that more magic. Some times it is better to marvel at the wonder than to see behind the curtain. But thanks everyone for all the science lessons.
Originally Posted by thisguysthumbs
This is something I think we can all agree with
Originally Posted by sisurfdogg
Too many 23 footers on the head. Thanks for the concern brah.
Originally Posted by seldom seen
Some good points made. As well, as usual, the obvious being stated.
Yes, it's great if you can walk to the beach & check it. If that were the case for the majority of people who utilize Surfline & SI....then there'd be no need for either website!
Yes, there's nothing like being out there in the ocean when it cleans up. And when the wind shifts or stays gorgeous for hours, esp when it was predicted otherwise.
My question was simply where does the windinfo come from for these websites & why does it differ so wildly?
I see what you did there; very clever; brah!
Originally Posted by yankee
I’m no expert, but here’s my understanding.
Weather forecasts start with observations. These are taken from all over the globe from places like airports, airplanes, satellites, etc.
These observations are fed into a handful of different supercomputers located around the world. These computers generate the weather models. North Americans mostly deal with the NAM and European models. Major runs are 0 and 12Z I think. This is why 6am and 6pm are when the most significant updates come out.
When there are too many variables the models will differ. Different sites that look at different models will show different forecasts. The models, and the various sites, will come into alignment as the variables decrease.
You used Sunday’s forecast as an example. Anything beyond three days is basically just a best guess. Once the different sites align (i.e the models align) you can be fairly confident in the forecast.
Needless to say SI is an outstanding clearinghouse for surf related forecast information. However its wind prediction won’t be any better than the model(s) it depends on.
One last note as to why the swell forecasts are more consistent than the wind forecast. The Navy produces the only swell model that I’m aware of. Makes sense that since there are no other models there’s no contradiction. Doesn’t necessarily mean the swell forecast is more accurate, just that everyone uses the same model.
Hope this helps.
I often find the difference in wind forecasts is simply because they are updated at different times. Wait till the next forecast update and see if they line up more.
I just compared swellinfo and windguru for AI/CI on sunday and they are looking the same right now.
Weather.com, on the other hand, forecasts winds a few miles inland so they generally aren't as reliable as sites that give forecasts at the shore.
I think most US based sites use GFS models for wind, but I wonder if MSW uses ECMWF. (Probably not since it looks like their wind forecast is the same as SI's)
Sorry Mr. Yankee, but the orgins of wind predictions for surf predictin' websites remains a mystery. NOAA would probably be a good guess. Actually, many a surf predictin' sites are basically the NOAA marine forecast altered to the coast(not open oceans waves) and dressed-up all fancy like. But heck, maybe they just lift it from The Weather Channel's Local on the 8's or tune into Channel 6 ABC/Philadelphia's David Murphy for the scoop. Yo, Murph!
Y'all realize, Mr. Yankee wasn't axing how winds come to be, he was axing where all of these surf predictin' sites get their wind info.
Since the guru powers that be haven't weighed in, I reckon it's an ancient chinese secret.
I do know that most surf predictin' sites don't rely on their fancy learnin' degrees to predict the surf. They all have a special magical set of dice. And then they roll them suckers and report the outcome. Ya know what it is that I be sayin' ? Oh golly, I'm just kiddin'.
If you click on Marine Forecast it gives you what you are looking for, and then you can even break it down by the hours if you want
Originally Posted by brek