metorological ?

[J. Dillon]

Can any one explain that sometimes on the approach of a high tide ( peak) their is often a wind shift or velocity change ? :rolleyes: I looked in all my books and could not find an answer. :(

JD

[Popeye]

nope, don't know. this could be one for the old timers. could be onshore offshore breezes weakly associated with tide time table? or the approach of a low pressure system out to sea that causes a surge? possibly no simple answer.

[ishmael]

Hmm. This should be interesting.

I confess to not being very weather savvy. Would you say Jack that there is a typical cycle of winds in your locale, that while not everyday can be found during certain conditions such as a persistent high?

I wonder if you are conntecting things that aren't connected, except coincidentally. In other words, you have experience of a shift in winds that is fairly typical for your locale around a given time, and have additional memory of the tide peaking at those times, all probably because that's when you tend to be on the water.

But I don't know. Do you have a log of your observations? That might be something to do, keep a record of where, and at what time, direction, state of tide, etc.

My scattered earth sciences mind can't see a connection, but that surely doesn't mean it isn't there.

[Ian McColgin]

In Long Island Sound, that's mostly caused by temperature shifts of the water mass as it moves in and out.

LIS is extremely interesting that way and races are won by those who know the drill.

[John C. Mannone]

While fumbling to log-on, Ian beat me to it and gave you the correct answer.

Though some of the other replies could apply, there is absolutely no expectation of wind speed or direction change based on incomming tides- a moon (and Sun) driven phenomena. The delta T sets the stage for wind flow.

John

[Scott Rosen]

Ian's right. In parts of Eastern LIS, you can literally see a line in the water where the turn of the current occurs. When ebb turns to flood, there's usually a freshening of the breeze from the Southwest. On the flood side of the line, the water is cooler and cleaner.

[John B]

As an aside, and not directly related to this question, it was always interesting to me that after a couple of days of offshore breeze, usually strong, the tide did not come in as far as it was supposed to. This was first pointed out to me by the man who ran our haulout area.( tide dependent obviously)

[ishmael]

Just to follow this along, what Ian and others are saying is that when LIS is full the colder water coming in from the Atlantic it causes a shift in wind because of its affect on the temp. of the air. Is that what you are saying? Are the shifts in water temp from low to high tide so pronounced? I suppose there is all kinds of complexity having to do with the mixing of surface and deeper waters, etc.

Complexity. I would never have thought of these things, but it makes a certain amount of sense. The places I've sailed, the coast of Maine, and lakes wouldn't see such effects, at least not so vibrant as to be very noticable.

[ 06-05-2003, 08:40 PM: Message edited by: ishmael ]

[Scott Rosen]

Jack,

I don't know the whys and the wherefores. I was only reporting what I've observed first-hand from years of sailing LIS.

[Ian McColgin]

The cooler ocean water will have cooler denser air over it. Especially in the afternoon, should low be around noon, the heating and rising air over the land will give you the onshore breeze - southerly on the Connecticut side and northerly on the Long Island side.

In one Off-SOundings race, the bulk of the fleet tried to find wind and ride the current along the southern side, as the finish was in Port Jeff. I skipped up past Fishers and along with a better wind that filled in dominating the whole sound by about sunset so I could reach across past Middle Ground (Stratford Shoal to thos barbarians from the rocky side) and win by a couple of hours.