shem
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| posted on 18-10-2004 at 12:23 |
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difference in wind!!!!?????
After reading Al and Dunks diary entries compared to mine for the 17th of october, I was well shocked at the wind differences. We had a
solid 20 knots at Aberdyfi, whilst they only had 13-14 knots, half a mile away at ynys las? Wierd. Every one was super powerd on 12s
and 13s on this side, there where even two 9 meters up. The sand was blowing up the beach, it was howling. WIERD!!!!!!
Maybe thats why there where 10 people riding at Dyfi side and only 2 ynys las.
Kite & SUP wales
Caravan decking wales
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col123
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| posted on 18-10-2004 at 18:39 |
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its all them sheep on the hills they got wind you know...you'll have to stop the farmer feeding them sprouts
To Infirmary and beyond..
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justal
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| posted on 19-10-2004 at 06:17 |
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Well, for what its worth, here's my explanation....
First up, I've checked all the bouys, weather stations etc. and everywhere along this stretch of coastline recorded wind speeds of
around 16 knots for most of the afternoon on Sunday from a NNW direction... Thats also the wind speed and direction I recorded on the
beach. We can dismiss any local differences caused by temperature gradients as at this time of year in mid afternoon, land, sea and air
temperatures are all pretty much the same at around 13¬?C. Similarly, with the wind coming in off the sea we can also be pretty sure
that the wind wasn't being funnelled by any local topographic features...
So, we can be pretty sure that the actual windspeeds were pretty consistent between graveyards and Ynyslas at around 16 knots. I went
quite a way upwind towards the point and sure enough, there was little difference there.
So, the next important consideration are the tides. Sunday afternoon saw the tide (a pretty big spring tide) in mid ebb. This means
that there was lots of water flowing out through the mouth of the estuary. I don't know the exact figures but I should imagine that the
water gets to around 3-4 knots as it flows through the deep channel past Aberdovey, it then flows out through the mouth of the estuary
at this speed where it hits the bar and the flow is defelcted both Northwards past Graveyards and around the bar and southwards to
Ynyslas. So, if you are something (a kitesurfer for example) floating on the water at Graveyards, you will be moving along with the
current at 3-4 knots striaight into (give or take a few degrees) a 16 knot wind, giving you an apparent windspeed of around 19-20
knots.... Exactly the windspeed that the guys kiting at Graveyards have reported. On the other hand, if you were at Ynyslas, the
current was pretty much in the same direction as the wind, so the apparent windspeed was 12-13 knots... Again, exactly what it felt
like on the water here.
So there you have it, an explanation for the 6-8 knot difference in useable wind on Sunday, all because of a 3-4 knot current and an
ebbing tide.... Theres more to decided where to kitesurf / windsurf than you might think!
Al.
URL: Pixelwave Design - Website Design Wales
Shop: Website Templates
Personal Weblog: A Simple Life of Luxury in West Wales
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leonardo
A Force-of-Nature ***  
Member #: 634 Posts 613
Registered: 8-4-2004 Member Is Offline Mood: Chillin' ya bloodclot mahn
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| posted on 19-10-2004 at 06:55 |
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Once again, a full detailed analysis on the local tide considerations to be taken into account provided by master Al - AKA the local
ICE Hockey windsurfing loopmadman 
Hey Al...you up for a barbie sat night?
LEN10 LOOPING..
www.sskiteboarding.com
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shem
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| posted on 21-10-2004 at 19:16 |
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Ye could well be the tide Al, The Aberdyfi side of the Estuary is super tidal, on big tides its actually up to around an 8 knot rip, (
dont wanna be dropping your kite in that)!! We where actually reading over 20 knots on the beach though. Wierd. Musnt grumble mind you.
Kite & SUP wales
Caravan decking wales
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Pixelwave Web Design.
justal@forces-of-nature.co.uk