There has been much flying at Woodstock lately. And conditions that were suprising to some pilots. I had some time to pore over an old thread from late August 2007 and am posting excerpts from it here for valuable reading. Enjoy.
The topography is the muffler
XCanytime wrote:
Marc,
The muffling effect that you mention is a phenomenon that I coined way back in 1997 the "Woodstock Gradient Effect (WGE for short)". I was mystified by listening to the NOAA weather stations reporting Winchester's conditions back in March of 1997 as gusting up to 28 MPH, and hearing from Geoff Mumford that it was 10 to 15 at launch and not bad aloft above the Woodstock launch when he flew that very day. This pattern repeated itself, and I theorized that the topography directly upwind of the Woodstock launch was higher and "shadowed" the local area. A look at the relief maps of the areas confirmed my suspicion, with the topography over the WV border at 3K to 4K MSL, and Woodstock launch is at 1900' MSL. This "gradient effect" draws pilots to Woodstock when the forecast is NW 15 to 25 MPH.
There are a few instances where the effect is absent. On very unstable days the shadowing effect is negated. Upper-level disturbances passing through the local area can mix up the atmosphere enough to bring higher winds down to launch level. Deep lows spinning in place over the Canadian maritimes with a tremendous pressure gradient will blow out Woodstock.
But if the weather pattern is a garden variety cold front passage and a typical high pressure behind the front, breezy conditions usually follow and chances are the effect will be present.
Bacil
I first heard the term "Woodstock effect" from Rob Millman when we flew there around 1990/91.
marc
The "Woodstock Effect" is definitely real. I've enjoyed many flights
there on days when surface winds at Martinsburg, Winchester, and
Hagerstown have been reported at 25 to 30.
Really. Not "talked myself into it" enjoyment, but actual fun flying.
On the other hand, I've also had a flights at Woodstock for which
the effect did not materialize, and the flying was not fun.
For some of those flights, the sky looked strong (wave) and the
conditions in-flight matched.
But there have also been days when the sky has looked just as strong,
but the flying turned out to be great.
Bottom line: While the effect is real, it's not guaranteed. By choosing
to fly at Woodstock on a strong day, you are assuming a higher
level
of risk. Maybe that risk is worth the reward... Or maybe it's not.
Depends on your comfort level in strong air, what you are flying, how current
you are, what you expect to 'get' out of flying that day, etc.
And make no mistake: Even if you are flying the hottest ship out there,
you can still get burned if conditions change. The sky can be a fickle place.
MarkC
Bacil, I agree with your assessment that due to a variety of topographical features there is often a "deflection" that apparently shadows winds down at launch levels.
My point is that the winds are still there aloft--they may just be deflected higher or lower. I also maintain that no matter how good you may be at forecasting weather--you're still tossing the dice on high wind days as to whether or not those winds may make a guest appearance at launch or the LZ. I myself have chosen to accept those risks.
Over many years of flying it has been a general habit of pilots to assume Woodstock is the place to go on dynamic passing or post frontal days. That's just the way it has always been.
In general, when flying Woodstock I have seen way way too many launches where pilots have been gusted straight up--sometimes rolled. I have seen way way too many crashes, treeings and blowbacks. I've seen way way too many pilots get low up against the ridge and fail to get out to or barely make a suitable lz.
Is this because the Woodstock effect also automatically causes pilots to fly worse?
So, as Mark suggests, you MIGHT get away with a smooth buttermilk flight when the rest of the region is howling--but you are just as likely to encounter some high winds at some point some place during your flight.
marc
Kurt,
I recommend lotsa reading and lotsa flying. The reading part should include Performance Flying and Understanding The Sky by Pagen. Those two books will help you learn more about the big picture. The flying will give you the experience necessary for advancing your skills and judgement. The key in flying is to always leave yourself an out, to keep a healthy safety margin and don't back yourself into a corner with no good options. In my opinion the Falcon does not provide you with a large enough window of performance to handle the myriad of weather conditions that we fly in with double surface gliders, and with a healthy safety margin. A prime example, in my opinion, is the very flight you describe from 2 weeks ago. An easy to fly double surface glider increases your range of flyable conditions, but the increased range brings increased risk as well. The common thread among all this is always leave yourself an out, no matter what glider you are flying.
Bacil
Actually, there's been no weather debate in this thread. Just some suggestions about what may cause sudden increases in launch level winds and some redefinition of terms. But to summarize all the silent knowledge without the terminology, it goes like this:
1. Winds up high depend only on the pressure systems, which are big lumbering dinosaurs that don't change just because the sun goes down.
2. Winds near the surface will be lower because of friction.
3. Convection (thermals etc) will stir up the air, so that some of the high speed wind above gets mixed down lower. This is what causes winds down lower to pick up in the middle of the afternoon, then eventually turn into a dead layer sometime in the evening.
4. Wave action works better in stable air, so thermally air may both decrease the wave and also mix it around so the effects are more felt at launch level.
5. The "woodstock effect" is almost definitely caused by the higher ridge in front of launch, but the details of how exactly this interacts with the 4 points above is a matter of speculation.
6. If you make sure the winds up high are not too much stronger than what you're willing to fly in, you've eliminated the primary danger. This is where we tend to push our luck at woodstock.
The main thing I've learned as a graduate student in meteorology is that a good HG pilot knows as much or more about this stuff than most meteorologists. Only a few practicing meteorologists specialize in the type of stuff we are interested in, so follow Bacil's advice and you'll become one of the world elite in the micrometeorology of winds and thermals.
Brian Vant-Hull
Woodstock Characteristics
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