Ground swell vs windswell

Do you mean as far as the accuracy of the forecast goes?

I'm no forecaster but if i had to guess i would say that because the difference between short period and long period swells is the distance they travel from their source, then the forecasting accuracy would be nearly the same. A storm is a storm and i would think you could forecast it just as easily whether its East of Bermuda or right off of Cape Hatteras.

The difference, i would think-- would be that its harder to figure out how the longer period swells will interact with your local Bathymetry... Making the ground swell a little more fickle for any particular beach. I've seen ground swells be overhead at one spot and then waist high a few miles down the coast.

So basically the forecasting models will be the same as far as accuracy, but ground swell could be more fickle at your local spot.
That's my guess anyway. Anybody know for sure?

I think there are also multiple topics on this site about ground vs wind swell if you search around.

 

I think the groundswells are more consistant than the windswells. Also, how clean they are going to be really depends on the winds that day. You could have a huge storm off the coast generating waves at 5ft 14 seconds but if you have winds from the south it will make it choppy and sloppy.

 

Keep in mind that when you get the higher periods of say 12 and 13 seconds or higher, you tend to start getting alot of closeouts.
Good rule of thumb...if it's a groundswell with a medium period, you get out; no questions asked.

 

If I recall correctly, although we all use the term ground swell, all of our swells are created by wind.

 

\r\n\r\nDepends on the accuracy of the forecasted wind swell. Like the guy said above, you want a medium period ground swell (9-12 seconds) for places like Va Beach with a shallow bathymetry vs. a long period ground swell focusing it\'s energy on deeper waters or reef/rock.\r\n\r\nGround swell gets people excited, whereas there are some windswell events that create a better quality wave depending on the angle of the beach in conjunction to what direction the wind swell is focused. An ideal swell would be a medium period combo swell from a northeasterly and southeasterly direction (for an east facing beach) that when combined would generate peaky conditions/a-frame type waves with less closeouts.\r\n

 

disingenius. thanks for not understanding the topic of the thread.

 

i've also found that longer period swells prefer a higher tide (at least around here) b/c this allows them to "feel" the bottom more gradually, allowing more of an opportunity for a rideable/makeable wave. long(er) period swells on low tide=close out city.

 

Great thread, lots of good info.

 

yes, all swells are wind swells but a longer period swell's energy dips farther below the surface and is effected by the bottom sooner (thus 'ground' swell). they're also thicker and denser and less effected by surface winds and tides though as others mentioned low tide can be more prone to close outs... but not always!

 

At 6 ft 14 second interval I was wondering when to bolt out of work today and surf for an hour. After reading this, I might wait for high tide.

 

gotta disagree...

Bottom line: Long period and strong offshores = barrels. period.

High tide vs low tide... that is totally dependent on your spot. I can already see it getting junky and struggling to throw over at many spots and we are 2 hours out from high tide. You want the best session today? head out around like 2 or 3pm and surf until you have wet noodles for arms. I usually prefer a building tide rather than outgoing but this morning the juice wasn't here yet. With the swell filling in throughout the day and the offshores staying steady, I expect to get shacked out of my mind this afternoon / evening.

Long period closing out.... depends on where you are surfing. Yes, many of the connected "peninsula" style sandbars will be more prone to close out in the long period stuff. Find a sandbar that has a defined channel to one side or both and that "close out" will act like a reef head with a gnarley take off and a long line. Even better yet- find a jetty or pier or even a rivermouth. I would give just about anything to be perched up at the new inlet in S-turns at mid-tide this afternoon. They need to open that damn bridge...

Pura vida dudes hope you play this one right. No need to sit in a crowd either, this whole coast is about go off!

 

Its hard for me to answer these questions simply, but in general my answer is that longer period swells are much easier to forecast long range then short period wind swell systems. BUT, hurricane swells, which tend to be longer period, are a beast in themselves, and should really be considered differently then other types of storm systems.

Short period swells (wind swells) are generated by wind systems near the coast and travel only short distances before reaching the shore. So, we are relying on the weather forecasting models to determine the wind X days in advance. This is can be very unreliable several days in advance, where a small change in the intensity or exact location of a storm system can make a big difference to wind swell generated so close to the coast.

Long period swells, generally travel a much further distance before reaching the shore and are generated in the open ocean rather then right along the coastline. These swells can travel many days before reaching the coastline. The reliance is thus less on the long range weather forecasting, because the swell has already been generated and we are now just using ocean physics to track the generated swell as it traverses through the open ocean. The ocean wave physics is very reliable. The challenges in long period swells becomes more about the local nearshore bathymetric influence (ocean bottom depths), where refraction/defraction and offshore shoaling increases as the wave period increases. This creates greater challenge on the wave modelling front, where offshore canyons, islands, reefs, etc can play big roles on the swells.

As of now, Swellinfo has a bit of issues with correctly modelling the local bathymetric influence of the longer period models in some locations, but good news is that we are very close to performing a big upgrade which is going addressing this issue and should make the forecasts excellent! I'm very excited to get this new upgrade out there. I am hoping this will be done in October.

 

Windswells blow.............

 

yeah its definitely not 1-2 feet in LBI right now

 

Mr. Swellinfo... when you're done with that, can you start working on something to make the winds blow offshore? Maybe some sort of giant, adjustable baffle system that can take local sideshores and turn them offshore?

Thanks in advance...

 

All I know is everything today on Delmarva was ground swell. Big and mostly un-makable groundswell. Saw a few really nice waves ridden but unfortunately none for me. Sat there for an hour and a half and never dropped into one. I will take a big wind swell anyday over those picturesque pile drivers, lol.

 

Agree with you zippy...

16 second swell period...looks good, but doesnt ride that good...your average sandbar might not handle it.

Today:

 

i got worked pretty hard today. the sets would come through and close out the entire sandbar, it looked like they were breaking below sea level they were sucking up so much. i popped up with a face full of sand after almost every wave