Winds Aloft

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Jason608

Pre-takeoff checklist
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Jason608
Working on my first XC and have a question.

I was going through AOPA and Foreflight XC planning and the winds are detailed for each checkpoint, even ones under 20NM. When I check DUATS and other resources the winds Aloft are reported by station, a much wider area. Maybe I forgot but is there a more detailed winds aloft forecast? Or are the winds being reported in the planning tools, even at 6,500' really surface winds?
 
If u check "winds aloft", you will get 3000', 6k, 9k etc.... Metars are giving you surface winds at that location.
 
Foreflight is just interpolating. No extra information. Its source is exactly the same as what you get on DUATS.
 
Ask your CFI. The winds aloft are forecast winds at the specified altitude.
 
jordane93 said:
Ask your CFI. The winds aloft are forecast winds at the specified altitude.
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Yes, have the question out to my CFI as well.

But, I think I am over thinking this. Yes, I understand the winds aloft are for certain altitudes (6,500') but the area is huge. The forecast covers some 200 miles before the next station, which means there is only one winds calculation to do for a 150nm XC.
 
Winds aloft can be the same in an area that "small" Check out www.windyty.com for an general representation of the winds over the world. Select your altitude at the bottom.
 
Jason608 said:
Yes, have the question out to my CFI as well.

But, I think I am over thinking this. Yes, I understand the winds aloft are for certain altitudes (6,500') but the area is huge. The forecast covers some 200 miles before the next station, which means there is only one winds calculation to do for a 150nm XC.
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Yes.

Which is why you don't take them too seriously. Plan for them, then leave some margin for when (not if) they are different.

The wind is what it is, not what the forecast says.

The winds aloft forecast is NEVER for ANY VFR altitude. Anything that presents it as such is interpolating the data, and adding noise. The forecast comes at 3000 foot intervals.
 
Jason608 said:
Yes, have the question out to my CFI as well.

But, I think I am over thinking this. Yes, I understand the winds aloft are for certain altitudes (6,500') but the area is huge. The forecast covers some 200 miles before the next station, which means there is only one winds calculation to do for a 150nm XC.
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Yep. It also depends where are you. In the NE, there are many stations close to my home airport so it is easy to get an idea of the winds and plan an XC accordingly. But remember, these winds are only for planning purposes.
 
Jason608 said:
Yes, have the question out to my CFI as well.

But, I think I am over thinking this. Yes, I understand the winds aloft are for certain altitudes (6,500') but the area is huge. The forecast covers some 200 miles before the next station, which means there is only one winds calculation to do for a 150nm XC.
Click to expand...

True, especially using DUATS reporting stations. In the past I noticed descrepancies from flight planners and my manual interpolation for interim waypoints. Investigating this I found that some flight planners use proprietary algorithums to calculate wind plan for a flight. Call tech support for your flight planner and ask them how they calculate it. Might be quite interesting.

Back to your comment about forecast covers wide area. Remember without good Pireps this is a guess, it is the best we have for planning, but once you get going your actual enroute could be different. Thats why we keep track of actual versus planned.
 
Go to youtube and look for "Weather in the Vertical," by CFII/physicist Ed Willams. He gets into the Skew-T and wind about 10 minutes into part 2 of his discussion.

Just a wind-related quickie: Go to http://rucsoundings.noaa.gov. Change the time to three hours. In the site box, type the three-letter (no alphanumerics like S67) identifier of up to six airports separated by commas, then click on HTML5. Give the chart a second to populate. Beneath the chart, click on Get Text.

You have hundreds of sites to choose from, not the half-dozen that the winds aloft forecast gives you, and wind change continuous with altitude, not every 3000 feet.

Bob Gardner
 
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MAKG1 said:
Yes.

Which is why you don't take them too seriously. Plan for them, then leave some margin for when (not if) they are different.

The wind is what it is, not what the forecast says.

The winds aloft forecast is NEVER for ANY VFR altitude. Anything that presents it as such is interpolating the data, and adding noise. The forecast comes at 3000 foot intervals.
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Really? 3000MSL isn't a VFR altitude? Hmm, could have sworn it was pretty much everywhere except Death Valley (and of course places where the ground doesn't permit it without violating the laws of physics).

Maybe I'm just stupid.
Oh wait...

§91.159 VFR cruising altitude or flight level.

...each person operating an aircraft under VFR in level cruising flight more than 3,000 feet above the surface shall maintain the appropriate altitude or flight level prescribed below, unless otherwise authorized by ATC:
...
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Soooooo pretty much anywhere the elevation is above 0 MSL and less than 2000 in congested areas, 3000 is in fact a valid VFR altitude. Of course so is 6000, 9000, and 12,000 even 15,000 in certain parts of the country.
 
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Metars only give winds at the surface. You can you the winds aloft link on Aviationweather.gov and find your nearest station for winds closest to your cruising altitude as well as other resources.
 
scottd said:
If you are talking about winds and temps you get on the ForeFlight "File & Brief" from Lockheed Martin, you are correct. However, that's not the case for flight planning calculations. Sure, there's always interpolation going on, but the resolution of the data used for those calculations is higher than you'd get through the standard FB Winds from DUATs or Lockheed Martin.
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No offense, Scott. I know you work hard on this stuff.

The MOS guidance might be much higher resolution (0.5 deg grid resampled off a spectral data assimilation model, right?), but it's not useful in Foreflight, at least not yet. The actual model runs every 6 hours, but Foreflight's processing of it is highly nonuniform in time and seems to bear little relation to reality.
 
bobmrg said:
Go to youtube and look for "Weather in the Vertical," by CFII/physicist Ed Willams. He gets into the Skew-T and wind about 10 minutes into part 2 of his discussion.

Just a wind-related quickie: Go to http://rucsoundings.noaa.gov. Change the time to three hours. In the site box, type the three-letter (no alphanumerics like S67) identifier of up to six airports separated by commas, then click on HTML5. Give the chart a second to populate. Beneath the chart, click on Get Text.

You have hundreds of sites to choose from, not the half-dozen that the winds aloft forecast gives you, and wind change continuous with altitude, not every 3000 feet.

Bob Gardner
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Bob, Those videos are excellent. Thanks for sharing that! The second one really helped me understand the SkewT much better.

Link to the second video if anyone wants to learn more about the SkewT: https://www.youtube.com/watch?v=SU_ecI-vcNY
 
Jason608 said:
Yes, have the question out to my CFI as well.

But, I think I am over thinking this. Yes, I understand the winds aloft are for certain altitudes (6,500') but the area is huge. The forecast covers some 200 miles before the next station, which means there is only one winds calculation to do for a 150nm XC.
Click to expand...

If you select the default Op40 initial data source on the Skew-T, the data is for a 40km grid. That's 21.6 nm (thanks, Siri). And you can select up to six reporting stations along your route if you select a three-hour time frame.

Just memorize the answers to the five winds aloft questions on the written and use the Skew-T for real-world flying.

Bob Gardner
 
For what it's worth, I'd love to see SkewT's added to ForeFlight.

Being able to automatically cache several of them for along the flight route via the "Pack" function would be even better!
 
I remember doing my instrument ride. He asked how I came up with the winds - I told him Skew-T and he had NO CLUE what I was talking about. I had to pull it up on his laptop.... he said "winds aloft woulda been fine". told him how skew t was just a touch more accurate..
 
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