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PM Winds at Rowena/Dougs
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johnl



Joined: 05 Jun 1994
Posts: 1089
Location: Hood River OR

PostPosted: Sun Aug 19, 2012 11:36 pm    Post subject: PM Winds at Rowena/Dougs Reply with quote

Okay IWindsurf forecasters. What has happened to the PM winds at Rowena and Dougs? I think I've gone three times now when there is a solid forecast for PM winds (usually 2pm on) and have hung out till 6pm when I usually give up (cause the winds are VERY holey and light). Any idea what is going on this year? Rowena used to be the call for post work windsurfing. This year, it's been dismal at best....
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isobras



Joined: 17 Jul 2012
Posts: 439

PostPosted: Mon Aug 20, 2012 9:40 am    Post subject: Reply with quote

That's why I usually don't drive until the wind is sailable, despite my drive being 70 miles. What I usually miss that way is the hour or so it takes the wind to stabilize and the swell to build ... no big loss. I also pay a LOT of attention to forecast discussions, looking for terms like "gusty" "brief", "immediately behind passing front", etc., and to the wind's behavior/wavefront as the same weather feature passes points further west. We can sometimes watch a spike or a sustained surge march past Stevenson, then Swell, then Doug's, Maryhill, etc. for an inkling of what it may look like further east. You corridor locals have fewer such data points to watch, but a least for the evening sites like Rowena and Celilo, you have Stevenson and Swell, FWIW.

This year in particular, these evening surges have often been brief spikes, often a waste of time unless you're there and rigged and always a swim risk. Sure, I miss some brief sessions this way, but considering the hassles involved, that's OK by me. The famous "evening kicks" out east have been duds this year. In a "normal" season, we often sail increasingly building winds until finding the state of Washington in the dark is a challenge, but not this year; the wind usually pukes much earlier, to our dismay.

And to iW's credit, their WRAMS model, the blue forecast line on their Dynamic graph, has sometimes forewarned us of the brevity of evening winds. When that blue line is a sharply peaked "tent" rather than a rounded or sustained arch or ramp, I'm suspicious. That model's amplitudes are a joke, but its shape is often quite meaningful. I watch it closely.

We can only hope this year's degraded pattern is not due to the rest of the nation's heat and drought, because that's projected ... FWIW ... to intensify, especially in the west, and to last beyond any of our lifetimes.

Bummer.

Mike \OO/
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scottwerden



Joined: 11 Jul 1999
Posts: 191

PostPosted: Mon Aug 20, 2012 10:06 am    Post subject: Re: PM Winds at Rowena/Dougs Reply with quote

johnl wrote:
Any idea what is going on this year? Rowena used to be the call for post work windsurfing. This year, it's been dismal at best....


Global warming. I say this only partly tongue-in-cheek. Weather varies so it is hard to say on any particular day what is cause and effect, but it is a certainty that global warming will change climate, which will change the weather, including the wind around here.
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windfind



Joined: 18 Mar 1997
Posts: 698

PostPosted: Mon Aug 20, 2012 10:27 am    Post subject: Reply with quote

Guys,

I am not remotely a Gorge expert but 25 years forecasting wind on the west coast has given me some insight into pressure gradients and wind.

The mental metaphor I use for pressure gradients is a river current flow. For a river the elevation steepness gradient makes part of a river placid, parts rapids and parts waterfalls. If ALL you were aware of was the elevation drop from the start to the end of the river you would assume the whole river would be just mild riffles. And you would never suspect the rapids and waterfall mid river. And that is where we are in the Gorge forecasting: too few pressure readings.

If most of the pressure gradient is concentrated at one stretch of the Gorge then that will be the wind focus even if there is a huge overall pressure gradient from PDX to out east. Whereas if the pressure gradient is more evenly spread then more sites will blow albeit somewhat weaker.

Check out my mock up imagery below. Today there is roughly a .13 pressure gradient from Portland to Hermiston. But if you look at the top map notice how the isobars, in red, and wind are concentrated in two areas. While rest of the Gorge has very weak wind.

Yesterday the Hatch was the pressure gradient waterfall. Look at the 2nd. map and notice how all the isobars yesterday were concentrated near the Hatch. This is where the pressure gradient was steepest. The fact that there was a very strong overall pressure gradient across the Gorge is not as important as WHERE the pressure gradient is steepest. One day we will get all of our sensors calibrated and you will have real time pressure gradient information at your fingertips.

So the real question John asked is why, this season, the winds have been so focused in the Corridor? My reasoning:

Much of this summer there was a blocking upper level ridge over the central USA so several thousand temperature records fell including many all time temperature records. However this ridge steered upper troughs and their gusty winds over the Pacific Northwest.

With more upper troughs passing near us the entire Pacific Northwest has been cooler with fewer heat waves than normal especially the desert.

So with the desert cooler the pressure gradient has been weaker and more focused in the corridor rather than more evenly spread.

Without a smooth spread out pressure gradient there is less of a thermal component to the corridor wind and less marine layer intrusion.

Without the steadying influence of thermal wind and stable dense marine air there have been many days with bob and blast conditions. rather than the normal strong and gusty winds.

In addition fewer people are making the trip out east because the heat producing blocking ridge over the Rockies has caused the snow pack to melt more extensively all summer. So the Gorge had abnormally strong current much of the summer spoiling the swell at narrower places out east.

Add it all together and you get a weird year.

Mike Godsey
weatherflow.com
iwindsurf.com
ikitesurf.com
sailflow.com
fishweather.com



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isobras



Joined: 17 Jul 2012
Posts: 439

PostPosted: Mon Aug 20, 2012 10:50 am    Post subject: Re: PM Winds at Rowena/Dougs Reply with quote

scottwerden wrote:
it is a certainty that global warming will change climate ...

As does global cooling, as well as flat global temps, as do ocean currents, ...
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johnl



Joined: 05 Jun 1994
Posts: 1089
Location: Hood River OR

PostPosted: Tue Aug 21, 2012 10:47 pm    Post subject: Reply with quote

Mike,

Thanks for the info. I think it will take some time to digest Smile One of these days I'm going to learn to understand this stuff and put you guys out of a job. Okay probably not. But my bigger question is how come all the forecasters were getting it wrong? Not just Iwindsurf, but also our Gorge Local forecaster. They were all calling for solid mid 20's all afternoon each time I went there and it was dismal at best.

On the other hand, today was NOT that day. Cranked in the early evening (4 - 6 that I know of). Solid 3.7 or smaller wind.
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mchaco1



Joined: 08 Sep 2010
Posts: 637

PostPosted: Tue Aug 21, 2012 10:52 pm    Post subject: Reply with quote

same thing in HR, everyone called for 25-30 plus all afternoon and it completely shut off around 2 or 3 (to my dismay out on my sinker)...not even enough wind to keep the sail cleared from the water....
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shredder33



Joined: 13 Jun 2000
Posts: 11

PostPosted: Wed Aug 22, 2012 12:08 am    Post subject: 50 + tonight at Doug's :) Reply with quote

Nuked tonight way over 50 in the middle. Epic Doug's. Smile
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windfind



Joined: 18 Mar 1997
Posts: 698

PostPosted: Wed Aug 22, 2012 10:23 am    Post subject: Reply with quote

johnl wrote:
Mike,

But my bigger question is how come all the forecasters were getting it wrong? Not just Iwindsurf, but also our Gorge Local forecaster. They were all calling for solid mid 20's all afternoon each time I went there and it was dismal at best.

On the other hand, today was NOT that day. Cranked in the early evening (4 - 6 that I know of). Solid 3.7 or smaller wind.


Hi John,

The basic answer is that the various models are often working as though this is a "normal" year in terms of temperature distribution, marine layer distribution and air stability. So they sometimes go for periods where they get either the windy zone wrong or the wind quality wrong or both. I don't forecast often for the Gorge but I do know that it is extremely difficult for a forecaster to look at 4-5 models in consensus about the wind and to make a contrary forecast.

For example yesterday The Wall had miserable winds when I was there from mid day to almost 5PM. I had several 10 to 15 minute 4.2 sessions and then a slog/swim back to the beach. All the models had the winds you described for most of the Gorge but the reality was very different at The Wall. However if you looked at the Maryhill, Marker 40 or John Day sensors it looked like mid 20's gusting low 30's all afternoon. The issue was air stability ie. density. The surface air was not dense so the wind was at sensor level but did not stay attached to the water. The models do not directly see that phenomena. So if there is a forecast for winds out EAST and you do not see lots of marine layer clouds clogging the corridor near Hood River or beyond be ready for sensors out east that accurately detect wind that may NOT reach the water surface reliably especially if you feel warm air at the launch.

You can click on the red dots on the map at the link below to see what the models are forecasting for air moisture (green color) at sites along the Gorge from E. to W. In the summer there is a rough correlation between marine layer presence and the green color. The more marine layer (green color) the steadier the wind and the more accurate the sensors. You can also see in these graphs the modeled wind ALOFT not at the surface.

http://www.atmos.washington.edu/mm5rt/rt/timeheights_d2.cgi?GFS+gorge

Notice how different the marine layer is today versus tomorrow.... according to the models.

Mike Godsey
weatherflow.com
wind alert.com
iwindsurf.com
ikitesurf.com
sailflow.com
fishweather.com



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shreddbob



Joined: 31 Mar 1987
Posts: 258
Location: Massachusetts

PostPosted: Wed Aug 22, 2012 10:25 am    Post subject: Reply with quote

windfind wrote:

If most of the pressure gradient is concentrated at one stretch of the Gorge then that will be the wind focus


Mike, great explanations. I'm wondering if a website like this Plymouth State one offers any "real" value. Is its apparent ability to be so detailed useful, or is it merely parsing down on a broad loosely accurate set of models/observations and of no real benefit?

http://vortex.plymouth.edu/sfccalc.html

Snapshots of yesterday at noon and 5:00 PDT below.

Thanks!
Bob

EDIT: I'm just seeing your post from two minutes ago. Local variables key I understand. That's where years of experience needed. Keeps us all on our toes.



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8-21-12 5pm.png
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Map centered on Portland KTTD.png
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