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FlyDunes
Since 09 Oct 2007
1034 Posts
Aloha
XTreme Poster
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 Mon Jul 21, 08 6:23 am SI Tide Predictions - Kelley Point |
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SI worked great yesterday from about 2:30pm until the tide changed at about 5pm. After the tide changed, it was junk.
I looked up the tide predictions and found that Kelley Point is the forecast site closest to Sauvie Island for tide prediction accuracy. Kelley point showed low tide at 4:58pm yesterday, and St. Helens was a surprisingly different 3:26pm. It doesn't seem like there should be 90 minutes worth of difference in tides between those two points, but I guess there is!
Here's the link to Kelley Point tide predictions:
http://tidesandcurrents.noaa.gov/cgi-bin/get_predictions.cgi?year=2008&stn=1038%20Astoria&secstn=Kelley%20Point,%20Oreg.&thh=+5&thm=26&tlh=+7&tlm=16&hh=*0.00&hl=*0.00&size=large
Based on this info, I'm predicting that SI will suck for after work kiting until this coming Thursday, and then after that anything over 10-12mph will work good for PM kiting at least through the weekend.
_________________
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rich
Since 30 Nov 2005
306 Posts
portland
Obsessed
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| Mon Jul 21, 08 7:10 am |
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| blow another 1/2 hour and make the drive to Jones. Wind was up when I got there at 2 and was driving hard and consistant when I left at 8. 4 kites total, lots of beach. No worries from the dirt heads.
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pdxmonkeyboy
Since 16 May 2006
6081 Posts
forever labled as the
retired kiter & motorhead Unicorn Master
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| Mon Jul 21, 08 7:52 am |
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The tide was really ripping for sure. The wind picked up after you all left but it took allot of work to get upwind.
Me and foil man were the only souls out there.
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kt
Since 16 Mar 2005
763 Posts
Portland, Or
Opinionated
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| Mon Jul 21, 08 1:20 pm |
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hey fly,
what do you make of the large gap between fri and sat?
07/23/2008 Wed 06:30AM LDT 1.3 L 10:24AM LDT 7.3 H 06:31PM LDT -0.1 L 11:07PM LDT 8.0 H
07/24/2008 Thu 07:20AM LDT 1.0 L 11:19AM LDT 6.6 H 07:08PM LDT 0.6 L 11:43PM LDT 8.2 H
07/25/2008 Fri 08:18AM LDT 0.7 L 12:28PM LDT 5.9 H 07:53PM LDT 1.4 L
07/26/2008 Sat 12:28AM LDT 8.4 H 09:28AM LDT 0.4 L 01:52PM LDT 5.4 H 08:49PM LDT 2.1 L
just curious is all. that data just doesn't look consistent.
kt
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FlyDunes
Since 09 Oct 2007
1034 Posts
Aloha
XTreme Poster
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| Mon Jul 21, 08 1:30 pm |
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| kt wrote: | hey fly,
what do you make of the large gap between fri and sat?
07/23/2008 Wed 06:30AM LDT 1.3 L 10:24AM LDT 7.3 H 06:31PM LDT -0.1 L 11:07PM LDT 8.0 H
07/24/2008 Thu 07:20AM LDT 1.0 L 11:19AM LDT 6.6 H 07:08PM LDT 0.6 L 11:43PM LDT 8.2 H
07/25/2008 Fri 08:18AM LDT 0.7 L 12:28PM LDT 5.9 H 07:53PM LDT 1.4 L
07/26/2008 Sat 12:28AM LDT 8.4 H 09:28AM LDT 0.4 L 01:52PM LDT 5.4 H 08:49PM LDT 2.1 L
just curious is all. that data just doesn't look consistent.
kt |
I'm totally baffled now that I've looked more closely at the data. Sometimes there seems to be a gap of about 4hrs between L & H tide and sometimes as much as 9-hrs from H to low. I would have guessed there'd be a more consistent interval, like the ocean tides.
I've never really tracked river tides before, so we'll need someone with river experience to explain this one!
_________________
Lets FLY |
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pdxmonkeyboy
Since 16 May 2006
6081 Posts
forever labled as the
retired kiter & motorhead Unicorn Master
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| Mon Jul 21, 08 1:38 pm |
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hmmm, obivously there is allot more variables for river tides. I can't get my head around why there would be such variability in the timing. The overall fluctuation is caused in part by the lunar cycle but the timing should be relatively consistent.
from that internet thing...
Tides that occur in rivers emptying directly into tidal seas. These fides show three characteristic modifications of ocean tides. (1) The speed at which the tide travels upstream depends on the depth of the channel. (2) The further upstream, the longer the duration of the falling tide and the shorter the duration of the rising tide. (3) The range of the tide decreases with distance upstream.
In a river the difference between the depths of water at high and low tides may be relatively large, leading to a marked difference between the speeds at which high and low tides move. The difference in depth between various points on the river also partially explains the second modification, or duration of fall and rise. In addition, the river flow, which may fluctuate widely, helps a failing tide but hinders a rising tide, increasing the difference in duration.
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kt
Since 16 Mar 2005
763 Posts
Portland, Or
Opinionated
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| Mon Jul 21, 08 1:54 pm |
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and what about the currents? so far this year, with such a heavy current, tides really havn't been an issue, at least for me staying upwind. i have had trouble staying downwind really and my trip into the beach usually consisted of 3 or 4 straight downwind runs.
anyway, i am going to try it now. freemont flags are flapping out straight and scappose is reading 10 and jones is 14 to 20.
wish me luck.
kt
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Spike
Since 13 May 2007
1414 Posts
Alameda
Spelling Expert
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| Mon Jul 21, 08 3:09 pm |
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A big part of it would be that the natural freqency of tide waves in the river may be very different than the frequency of the tides on the ocean.
Its similar to tilting an aquarium, if you tilt it at the right frequency, you can create huge waves with just small tilting, but if you go off this natural frequency, the amplitude and period of the wave becomes very eratic. The river does this on a huge scale.
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Gman
Since 11 Feb 2006
4911 Posts
Portland
Unstrapped
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FlyDunes
Since 09 Oct 2007
1034 Posts
Aloha
XTreme Poster
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| Mon Jul 21, 08 3:23 pm |
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| pdxmonkeyboy wrote: | | ...The further upstream, the longer the duration of the falling tide and the shorter the duration of the rising tide. (3) The range of the tide decreases with distance upstream... |
So, your good info tells me two things:
1). Jones should be hit way worse than Sauvie Island by tides. I guess we don't hear too much about that because not as many folks make the trip to Jones, and secondly cause it blows harder there.
2). Rising tides suck, but those are the short tides on a river. So there's a silver lining. Once we're back to the offset when the falling tides happen in the late afternoon, then our after work sessions will be made better by the tide assist.
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