Wind forcast Saturday

Ruffles

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26 Feb 2004
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Boat: Portsmouth, Us: Stewkley
www.soulbury.demon.co.uk
I'm supposed to be sailing to Weymouth on Saturday from the Solent. Fair tide from Hurst from around 10am on. However the wind is forecast at NE 3 knots.

How far off shore should I go to maximise sea breeze affects? Should I vary the distance depending on the time of day?

Rob.

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By definition, sea breezes are caused by the proximity of water to land and blow onshore. The further offshore you go, the weaker the sea breeze. Direction is also very local so if there is a sea breeze (and it relies on temperatures on the day) don't rely on it being from the same direction as the general forecast

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In the Solent a light offshore breeze will often kick start a good seabreeze quicker than an onshore one, by helping the convection cell to get going.
Having said that, The Dorset shore is different and I have a particularly strong memory of a windless (and engineless) passage through St Alban's race and back when the NE 5-6 cancelled out the seabreeze. I suspect the hills had something to do with lifting any airflow over them so I'd go for further offshore, based on my (one) experience of the area under similar conditions. You can bet that whichever choice you make, the other one will be the right one!

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Sea breezes are caused by the sun heating the land faster than the sea. As the warm air rises over the land (generally indicated by the cumulus clouds developing about mid morning, thermal activity doesn't always form convection clouds however) cooler air is drawn in from the sea to replace it.

Conversely when the sun goes down the land cools down and an offshore breeze kicks in....

Any sea breeze can be "over ridden” by a prevailing wind, but with very little pressure gradient with the forecast high, wind is really quite unlikely.. If the temp of the air above is warmer than the lower air (a temp inversion, looks like a murky skinned bubble from above) no thermal activity will occur, no rising warm air over the land = no sea breeze.

Ian


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I'd plan on using the engine too....the Forecast around Start Point (maybe a little further West, but not far) for the weekend is variable force 1-2, which in my experience (my boat is in Plymouth) means bugger all wind!!

<A target="_blank" HREF=http://www.met-office.gov.uk/weather/europe/uk/devoncornwall.html>http://www.met-office.gov.uk/weather/europe/uk/devoncornwall.html</A>

Have fun.....gasmasks/clothes-pegs at the ready for the fumes!!

Nick

<hr width=100% size=1>Byeee...Gone Sailing!!!!
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