Breeze..... Why does it.......
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Category: General
Forum Name: Banter
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URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=6814
Printed Date: 30 Jun 25 at 4:53pm
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Topic: Breeze..... Why does it.......
Posted By: didlydon
Subject: Breeze..... Why does it.......
Date Posted: 08 Jun 10 at 7:39pm
Ok. Have I been imagining this....?
 Having lived all my life
by the sea, ..... I think I've noticed that when high tide comes the breeze tends to drop. And, why does the breeze drop towards the evening? Naturally, I'm talking in general terms, on calmish days, without howling gales forecast. Any ideas from you meteorologists out there??  ------------- Vareo 365 |
Replies:
Posted By: Skiffybob
Date Posted: 08 Jun 10 at 7:41pm
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When the tide comes in, it's full so has a snooze, and at night it goes to bed. Don't you know anything? ------------- 12ft Skiff - Gordon Keeble and the Furry Fly-by AC - GBR271 - Whoosh B49 - Island Alchemy |
Posted By: JimC
Date Posted: 09 Jun 10 at 8:44am
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Evening:
In general there is more wind high up, because the wind is slowed by friction with the surface. This slowed area is called the boundary layer. During the day the thermal effects created by the land (or sea, but to a lesser extent) cause turbulence in the boundary layer which brings breeze, and especially gusts down from higher up. This affect reduces as the land cools down in the evening. High tide? no idea. I'll go with Bob's explanation... |
Posted By: Laser 173312
Date Posted: 09 Jun 10 at 9:28am
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This is my understanding of sea breezes rather than gradient wind which is what you are talking about here. On shore breezes occur on sunny days because the land is heated and is warmer than the surrounding sea. So the warm air over the land rises and sucks colder air off the sea causing an on shore breeze. As evening approaches the land cools back towards the temperature of the sea so the effect diminishes and the wind drops. Later in the night the land will be colder than the sea so an offshore breeze may be generated as the now warmer air over the sea rises. In both cases at a higher altitude there will be a breeze in the opposite direction to set up a circulation so that a piece of air will go round and round some think like
The tide effect on dropping the breeze I think is due to the fact that when the water comes in over the warm sand the water is heated and the sand cooled so that the temperature difference between the mainland and sea is less, hence the breeze dies. No doubt someone will know more than me ------------- |
Posted By: G.R.F.
Date Posted: 09 Jun 10 at 10:05am
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Lot depends on what's on the land in front of the tide.
Often as the tide comes in, in coastal towns like ours at Hythe, it brings you nearer to the buildings and as everyone who has read their tactical books knows, buildings effect the wind in front of them to the approximate of five times their height, (personally I think it's greater than five but that's the formula books are set on). So the wind does appear to increase as the tide comes in, but at the peak the combination of the waves, and any buildings present cause turbulence which the general airflow raises above and over, creating the impression that the wind is less, it remains gusty though. As to the wind always dropping in the evening, it is not always the case, we were racing(boards) last night it stayed pretty constant, in fact got up a bit now and then, but then the tide was coming in, had it been going out, I suspect the reverse would have been the case. Then there was no significant thermal activity last night, just a general weather pattern shift to the right which is also better, Southerlies are dead onshore and no matter how windy always suffer from the buildings effect close in so as it shifted a couple of degrees to the South West it cleaned up a tad, as did a canny old hand who spotted that and the tidal lee bow it presented - four bullets in fact.. ------------- https://www.ease-distribution.com/" rel="nofollow - https://www.ease-distribution.com/ |