Before criticizing any forecast source ...

isobars · Joined: 12 Dec 1999 Posts: 20935

There was a post here lambasting iW forecasts, before a moderator justifiably swept it away because it was too personal. The primary complaint was of a forecast for westerlies @ 20 but actual conditions easterly @ 3. For those who saw it, or were a target of it, or have felt like doing the same thing yourself, consider the following:

We stared slackjawed at the eastern Columbia River one day this summer at significant whitecaps -- probably about 20 mph -- in front of us. What was so unusual about that? It was a clear day, with no squalls anywhere, but if we looked to our right the wind was from the west by eye and by sensor data for tens of miles; if we turned our heads 90 degrees to the left, the wind was from the east by eye and by sensor data for tens of miles.

Are you kidding me?

Can you imagine being hooked to a kite at the collision line between those two sustained air masses meeting head-on in a confined gorge?

How can anyone forecast that?

This is no joke: I was earnestly told that one guy approached the shore, made a u-turn, and sailed back across the river without having to change his feet or hands on board or boom, planing most of the time.

More than once we have sat beside Elephant Butte Reservoir in NM as very low clouds blasted out of the west at a measured (by sensors at the nearby airport) >30 mph all day -- we could sometimes hear it, and low birds were obviously being blasted by it -- while we chucked rocks into the water in easterly breezes of 5-10 mph all day.

How does anybody forecast those conditions? NOAA tried and failed in both scenarios with their megabucks and Crays. And one day this summer we saw EVERY other forecast source expect major winds all day while iW said very specifically a full day in advance, No Way; everybody else is wrong! ... and iW was right … that time.

I never rely on any one forecast, and it's not surprising how often disagreeing forecasts for tomorrow merge overnight. This ain't rocket science; I've been there, done that, and meteorology is MUCH tougher, largely because butterflies don't mess with Saturn V's.

Mike \m/

gmclean · Joined: 08 Mar 2001 Posts: 91

Here is a screen shot showing wind speeds and directions from last Friday afternoon. It was interesting to see the building easterlies at Maryhill due the upper level NE flow associated with a back door cold front while the central gorge was still under influence of the westerly surface gradient. Weather is never boring here......

Bret · Joined: 28 Apr 2006 Posts: 149 Location: Up State New York

I wasted many "bucks" $4.39 a gallon this summer on many "bogus" forecasts from I do not surf.com

isobars · Joined: 12 Dec 1999 Posts: 20935

So why don't you use all the other forecasts -- they're all free -- instead of iW? That ... or wait 'til it's actually BLOWING to leave home?

pabloson · Joined: 27 Jul 2001 Posts: 20

Weather is so fascinating. My wife and I were driving across the toll bridge the other day over glassy water. Just to the west there were westerly white caps. My wife asked a question I have often pondered: Where did the wind go? I mean, it can't just come to a stop, can it? Did it go up?

George?

isobars · Joined: 12 Dec 1999 Posts: 20935

Up is certainly one correct answer.

Another is highly localized gradient, such as between adjacent pieces of surface at different temps, such as water, lawn, asphalt parking lot, dirt, forest, etc.

Another, or a variation on the above, is that when a "chunk" of air rises, as it will above an acre or a square mile of dark surface on a sunny day, another "chunk" of air must sink to the surface to replace it. If that chunk of air is moving laterally -- i.e., if there's wind up there -- it will maintain some of its lateral motion as it sinks to the surface. If the rising air mass is the size of a county or state and the wind "up there" is the jet stream, take the day off work and drive; it's gonna be a warm, windy day when that jet stream sinks to the surface to replace the rising surface air. Then when the surface cools at dusk, you need to be near shore in case the jet stream lifts off the surface and leaves you stranded in mid-jump.

There's a whole book on just micro-winds, as small as an acre or a gap in a shoreline hedge. It's very useful for sailors trying to maximize anything from speed in a race to the odds of getting back to your lonely dog at feeding time. It's just one of many excellent, practical, laymen's weather books written by Alan Watts, all focused primarily on sailing winds.

Mike \m/

isobars · Joined: 12 Dec 1999 Posts: 20935

That was true, too, with Windsight and the Gorge radio station WS forecasts, not just iW or any one forecaster. We've all seen days when the morning fx and midday updates were for light breezes, despite the fact that we were on 3.7s from 5:00 AM 'til after supper. I've had Doug's, Rufus, and Roosevelt to myself on 3.x sails from dawn until near noon in the days before pagers because morning forecasters forgot to look at current data. Alas, those days are gone. OTOH, pagers make my day every day, such as yesterday's unforecast big, smooth swell and 4.0 wind out east.

Mike \m/

jingebritsen · Joined: 21 Aug 2002 Posts: 3371

I've come off the White Salmon road headed back to town from a mtn bike ride one or twice where the event site is glassy, and the Hatch is buzzing. Pretty remarkable when one looks left for traffic, then right too also see glassy, then the Hatch off in the distance getting some action!

Where does the wind go? It behaves like water sometimes, but not others. Since air is compressible, this can happen.

Berta · Joined: 17 Jun 2002 Posts: 8

I think Kent is right...this was a really bad year for the forecasts! I dont mind it being wrong, theres a certain amount of leeway when forecasting the wind, its when the forecaster is being half assed that sucks.

The 11:30 update is to fix those early morning blunders, and set us back on course. Yet so many days they failed to even look at what the wind is doing at that moment, with 11:30 updates obviously rushed with nothing "new" to speak of at all. "Hello...did you notice that swell was 27...?"

"but but but the models said"... dude, look out the window, or check the website you work for

Temira · Joined: 15 Jun 1999 Posts: 94 Location: Hood River

Hey, give the forecasters a break. This summer was VERY difficult.

Why?

Normal gorge setup is high pressure off the coast and low pressure in the desert. In a typical summer, this happens most of the time in the Gorge. This year we had low pressure off the coast. The wind was generally driven by fronts.

Fronts, and their associated pressure gradients, are hard, very hard to predict in the Gorge. The passage of a front determines the timing/strength of the wind, and fronts can stall or dissipate, rendering incorrect the most studied of forecasts.

The "normal" and easy to predict setup happened only 3-5 days this summer (plus a couple of times after labor day).

As for Stu Hill, he's always the one who gets the forecast right when I blow it. If I hear that Stu said something different than I did, I worry.

Finally, of all the forecasting areas in the U.S., the Pacific Northwest is the most difficult. The most difficult area of the PNW to forecast is the Gorge. Taking this logic to a conclusion, the Gorge is the most difficult place to predict in the entire USA.

Temira