Tropical Storm groundswell duration

You are correct in that the longer period waves do travel faster and we'll see them first (since they move quicker they reach the destination sooner). The speed of waves is correlated to the period. Longer period = faster waves. I don't know about the time frame of days you were speaking of though, gotta hope someone else posts haha.

 

This is so far out right now I wouldn't be getting to excited just yet!! Just cross your fingers and hope, but don't count on it.

 

I hope that Micah jumps in soon - latest NWS discussion on Bertha states that she should be a hurricane in 72 to 96 hours!!!! She's going to be hitting some cooler waters, but wind shear doesn't appear to be an issue right now.

I'm wondering if she's going to be one of those ferocious little Cape Verde numbers...

Yeesh.

 

Should become subtropical as well.

 

one of the most important aspects for the tropical storms is the direction it is moving. The storm is very far away from us... however if it produces winds in our swell window and is moving towards us, then it can produce waves our way.

At this point, it is just barely at tropical storm status, but it does have a good path on it. For us to get any substantial swell, we need the wind speeds to increase a bit. The winds are forecasted to increase over the next few days, however the NHC still has this storm under hurricane status.

At this point, I wouldnt expect anything big from this storm, but at this point, I'm thinking we could see a few days of fun 2-3-4' stuff. The main negative factor right now is the storm is moving towards colder waters.

 

If you want to simplifiy things the velocity of the wave form in translation is just a simple non-linear equation of:

In shallow water, where we would surf, v = sqrt(gd), where g=32.2 ft/sec^2 and d is the depth of the ocean at that point.

In the open ocean, v=sqrt (gP/2pi), where P=period...and because P is in the numerator the speed increases therefore faster swells.

How long it takes is basically distance/velocity, so determine where you want to determine the time from and divide by the velocity from above.

One thing that is also working our favor is the track as Micah had eluded to because IF Big Berfa maintains the same track for a certain time duration, a phenonmenon known as virtual fetch develops and just like normal fetch, it will send waves propagating in the mean direction.


Hope this helps with your forecasting

Birdman.
________
headshops

 

BIRDMAN...WHAT THE HECK ARE YOU TALKIN' ABOUT?????

 

A thing to keep an eye on with this storm is it's recurvature. This will be dictated by the strength of the storm. A stronger storm is going to recurve earlier. A weaker storm would have a chance to make it as far as Bermuda in it's recurvature.

Overall the system has an extremely low chance of giving us anything spectacular in the form of swell. Maybe an elevated day or two at best but it might not even do that.

Check back in five days to see where it's at before really watching it in terms of your own plans.

 

I would take one or two days of groundswell. Those days of little Southern Hemi swell were pretty sweet.......although small. Groundswell makes such a difference, I'll take whatever I can get....

 

Isnt groundswell generally better than windswell? Like i kno what some of the differences are how ground comes from a low pressure and wind comes from wind. But what are others?

 

both are generated from wind. the difference is how far away the swell is produced and the time for organization.

 

It appears that the system has remained weak enough to stay on a more westerly track thus far.

There is now a much greater chance this system makes it quite a bit west of Bermuda than two days ago when it was largely forecasted to intensify making it more susceptible to upper level winds that would have steered it north into the central atlantic.

I'd still wait at least another three days before any excitement for even though it is clearly going to move much closer to the US coast than originally thought there is a lot of wind shear and dry air environment ahead of the system and it could be torn apart before it became a significant system far enough west to greatly impact our swell.

Stay tuned....

 

There's a lot of difference of opinion going on over Bertha's track. Weather Underground is already stating that PR/DR should possibly be getting ready for tropical storm conditions and that Bertha will be a threat to the East Coast (NC) in 10 days, and I read nothing of that on the National Hurricane Center's website. I guess people are being alarmist being that they are predicting strengthing on Sunday.

 

The difference between groundswell and windswell is the swell interval. Longer period swells are the result of an area of low pressure with a large area of fetch in our swell window. The bigger the storm, the stronger the winds, the longer and larger the period of swell. All groundswell starts out as windswell, the wave trains become organized and move in a predictable pattern.

Groundswell is much more organized than windswell and much more powerful. I had a better time in 1-2 foot at 15 sec like we had 3 weeks ago than our usual 3-5 feet at 7 sec. Sure, both are fun - but groundswell is a *definite* difference.

 

bull **** no where can handle 15sec intreval it would be almost all closeouts

 

Curt, I'm afraid you have not idea of what you're talking about. Long period swell is almost always more desirable then short period. Yes, a long period swell that is directed at a beach break straight on will tend to close out, assuming there are no sand bars. However, I would love to see a long period swell hit OC with a lot of North or south direction in it. Way more energy and much longer rides than any short period swell could possibly produce. If you need to see for yourself, go to any one of many web sites, look at historical data, and you will find that ALL of the world's best breaks are located in areas that receive mostly LONG PERIOD ground swell and NOT short period wind swell.

 

A lot of beaches in Delmarva can't handle a big long period swell and will close out. However when we get small to medium size long period swells, then there are spots that can handle.

Generally speaking, I think the ideal swell period for the Mid Atlantic is in the 9 to 12 second range.

Saying groundswell is better than windswell is not really a good statement. a 3ft @ 14 second swell will have a lot more energy than a 3ft @ 7 second swell. However a 9ft @ 7second swell can be great too!

The term ground swell was created, because the longer period swells are much more influenced by the ocean bathymetry (bottom contour/depths).

 

It was ONE to TWO feet ESE swell at 15 seconds, not 20 feet at 15 seconds. Go back and look at historic information on your local buoy, it was a Southern Hemi swell from about 3 weeks ago.

 

it happens.