Woodstock Tomorrow (1/18)

[Ward Odenwald]

Could be good. Forecasts are indicating solid ridge lift conditions along the entire length of the Massanutten ridges all day. Will get an early start if the forecasts hold. Any interest?

Ward

[krryerson]

Greeee, have to work.... can't make it.... Knut

[markc]

Whoa, where'd that come from? Had slated tomorrow for telework and Thurs for a vacation day, but maybe I should reconsider.... Will at least take a look at conditions tomorrow, though not sure I can rearrange the work stuff.....

[wmelo]

I am interested! I may be able to be there by 1:00pm with my falcon. Would it be a falcon day?

[markc]

Hmmm...

Bit of a gamble Walt, but not crazily-so. G20 gust factor in the surface forecasts between noon and 3pm. And 20-30 in the ADDS 3k 3000' forecasts. But velocities are supposed to back off (at least, as of tonight's forecasts).

And if the "subtract 5-10" rule-of-thumb for WS holds... Then yeah, it might be Falcon-able!

If I was on the fence (based on the glider/conditions), I would probably base my decision on the vacation days that were available to me. If not many, a gamble during spring or fall might yield a more memorable flight. Then again, could be a rare mid-winter chance to fly...

"Do you feel lucky?"

[Ward Odenwald]

Yes, I feel lucky! Gust factor for two of the three forecasts has backed off (mid to low 20s at 3pm) and the direction is still good. ETA at launch 8:30.

[Ward Odenwald]

DNF. Short reason why –> wave dominated conditions at launch. Once ready (~10:30), the 8 to 12 mph west cross in the slot rocketed to 20 - 30 mph and the air was blowing from what seemed like all directions including down drafts. Juan and I spent the next 20 minutes trying to keep the glider intact while watching the trees do their crazy dance and the turbulence shred the streamer tape into confetti that swirled in all directions. The ramped up disappeared as fast as it arrived only to be replaced with nothing; that’s right, nothing - no tree movement, no sound of the wind in the distant trees and little or no streamer movement. This lasted for ~ 10 minutes and was followed by a repeat of the aforementioned chaos. After several cycles of this, I realized that the good looking parallel wave roll clouds running north to south in the valley including one directly above us indicated that a shifting wave was most likely the cause of both the explosive turbulence and the calm/little or no ridge lift conditions between them. Whatever the cause, for safety reasons, I broke down (mostly during the calm pauses). I’m not sure if a wire crew of three or more would have changed my decision not to fly, given the intensive turbulence during the ramp ups.

Another indication of just how dominant the wave conditions were today was that there was no visual suggestion of west to east lateral shift or drift of the roll clouds during the ~3 hrs after the no fly decision.

Ward

P.S. I still feel lucky

[Danny Brotto]

Hi Ward,

When sailplane pilots go racing down a ridge like the Massanutten, their bane is encountering a condition called "wave suppression".

For many miles the winds could be strong and solid NW but at certain patches on the ridge if/when this wave suppression sets in it sometimes effectively cancels the ridge lift. When ridge flying in sailplanes its said that within minutes of being on a seemingly strong and solid ridge, you could end up in a field. Does not happen often but when it does, it gets your attention.

I'm not saying that you were witnessing first hand at ridge top this phenomena but it sure seems about that way.

Glad that you were on the ground wishing you were in the air than the other way around .

Danny Brotto

[XCanytime]

I remember years ago talking to one of the sailplane pilots (Kolie Lombard?) flying out of Front Royal about his flight encountering that very thing (suppression of ridge lift by wave activity). He was forced to land out at Sandy Hook, a flood plain of the North Fork of the Shenandoah just south of Strasburg. After he had a decent landing to the NW into a slight headwind, he proceeded to pop the canopy open and said it was almost ripped off its moorings by a strong gust/flow of wind from the SE! Ward mentioned that a wave/roll cloud was directly above the launch. In theory there is a "tumbleweed" of air located somewhere below the wave crest rotating in place. The tumbleweed location can also vary horizontally and vertically, so it's easy to visualize a strong downflow of air from the front side of the tumbleweed striking the windward side of the ridge, suppressing any flow up the ridge. The scrum between the two opposing airflows gets won by the downflow, resulting in the air flowing down like water to the base and continuing to flow to the NW until it stops some distance from the base of the ridge. This is one possible explanation of the forces that created the avalanche of air that almost took the canopy off of the sailplane, and also may have been what caused the phenomena that Ward and Juan observed. Bacil

[Ward Odenwald]

Taken from launch just before leaving around 2:30pm. The roll clouds out in front and above launch formed just before the first significant blowup around 10:45am.

[Danny Brotto]

I was about to note that while wave suppression can occur, but it's not frequent as most of that mess occurs pretty high off the ground (in the form of rotor) but darn those lennies look low! What would you estimate the altitude of the lennies?

Danny Brotto

[Ward Odenwald]

I’m guessing their base was mid 3k msl.