Winds aloft data source

[MacFlier]

I'm working on my first x-country flight plan and part of that to figure out the wind correction angle for the course.
My CFI is using the winds aloft data from aviationweather.gov but I thought we had to do a lot of guessing and approximations.
I know now pilots just get the wca directly from foreflight but was wondering what other sources I can use to impress the DPE later down the road...

 

[jordane93]

Aviationweather.gov works fine. Not sure how you’re going to impress the DPE

 

[eman1200]

aviationweather, usairnet, 1800wxbrief, windyty. all of which your DPE has been long aware of, so you won't be 'impressing' him, but all of those have winds aloft. also, most of weather forecasting is 'guessing and approximations', as you can tell from any weatherperson on the tele.

 

[RyanB]

Winds aloft are winds aloft, doesn’t matter which source you obtain them from. Any wind data will have the same altitude values so yes, you will have to estimate for the altitude you plan to cruise at and that’s called ‘interpolating’.

As Jordan said, I’m not sure how you’ll impress the DPE. It’s all standard procedure across the board.

 

[MacFlier]

aviationweather, usairnet, 1800wxbrief, windyty. all of which your DPE has been long aware of, so you won't be 'impressing' him, but all of those have winds aloft. also, most of weather forecasting is 'guessing and approximations', as you can tell from any weatherperson on the tele.

I'll check these other sources, thanks!
I thought I could come with an exact dir/speed using a equation or something.... That would impress him... Lol

 

[bobmrg]

I'll check these other sources, thanks!
I thought I could come with an exact dir/speed using a equation or something.... That would impress him... Lol

Don't lose sight of the fact that the winds aloft sources are all forecasts, not observations. The FB (Winds and Temperatures Aloft) is especially notorious for being wrong because (1) it is based on information from about 200 locations across the country, which is a very small sample; (2) its 3000-foot spacing between values leaves a lot of possibility for wind shear between values; (3) it is most accurate (ha!) when you fly directly over one of the reporting stations at exactly the right pressure altitude at the valid time; (4) it requires interpolation. Winds aloft forecasts are good for only one thing: determining whether or not you have sufficient fuel plus reserves to make the planned flight based on estimates. Once the wheels leave the ground and you become subject to the ACTUAL winds, all bets are off. Garbage in, garbage out.

The Skew-T is better in that the number of reporting sites is almost limitless, when you can designate at latitude-longitude as a reporting site; the pressure altitude is a continuum, not divided into 3000-foot slices; and you can ask for forecasts as much as six hours ahead. It is still a forecast, not an observation, but with more data points the accuracy is improved.

The FB is good for only one thing: the written. For practical flying it is a rubber crutch.

Bob Gardner

 

[sarangan]

Most flight planning software will interpolate between the stations, but in the old days we simply used the nearest station value. The difference between the two methods is minimal, so if you are thinking of using an even more exact method, its unlikely to produce any more useful information.

 

[sarangan]

Don't lose sight of the fact that the winds aloft sources are all forecasts, not observations. The FB (Winds and Temperatures Aloft) is especially notorious for being wrong because (1) it is based on information from about 200 locations across the country, which is a very small sample; (2) its 3000-foot spacing between values leaves a lot of possibility for wind shear between values; (3) it is most accurate (ha!) when you fly directly over one of the reporting stations at exactly the right pressure altitude at the valid time; (4) it requires interpolation. Winds aloft forecasts are good for only one thing: determining whether or not you have sufficient fuel plus reserves to make the planned flight based on estimates. Once the wheels leave the ground and you become subject to the ACTUAL winds, all bets are off. Garbage in, garbage out.

The Skew-T is better in that the number of reporting sites is almost limitless, when you can designate at latitude-longitude as a reporting site; the pressure altitude is a continuum, not divided into 3000-foot slices; and you can ask for forecasts as much as six hours ahead. It is still a forecast, not an observation, but with more data points the accuracy is improved.

The FB is good for only one thing: the written. For practical flying it is a rubber crutch.

Bob Gardner

Bob, I thought that skewT observations came from the same reporting sites as the winds aloft.

 

[bobmrg]

Andrew, If the FB comes from about 200 reporting sites and the Skew-T can come from thousands, there will obviously be instances where they coincide. You can get a Skew-T diagram by entering ANY airport designator (not alpha-numerics like S67, though); you can get a diagram from ANY latitude-longitude point in the US. So they are not limited to RAOB sites. View "Ed Williams YouTube "Weather in the Vertical" for a quickie course in Skew-T. See also the airports listing from the rucsoundings home page:

Instructions | Site info: METARs, RAOBs (Latest RAOB times), Airports (in another window) | version history (in another window)

The final product comes from computer models, which take data from observations and plug them into historical norms.

Bob

 

[MacFlier]

Don't lose sight of the fact that the winds aloft sources are all forecasts, not observations. The FB (Winds and Temperatures Aloft) is especially notorious for being wrong because (1) it is based on information from about 200 locations across the country, which is a very small sample; (2) its 3000-foot spacing between values leaves a lot of possibility for wind shear between values; (3) it is most accurate (ha!) when you fly directly over one of the reporting stations at exactly the right pressure altitude at the valid time; (4) it requires interpolation. Winds aloft forecasts are good for only one thing: determining whether or not you have sufficient fuel plus reserves to make the planned flight based on estimates. Once the wheels leave the ground and you become subject to the ACTUAL winds, all bets are off. Garbage in, garbage out.

The Skew-T is better in that the number of reporting sites is almost limitless, when you can designate at latitude-longitude as a reporting site; the pressure altitude is a continuum, not divided into 3000-foot slices; and you can ask for forecasts as much as six hours ahead. It is still a forecast, not an observation, but with more data points the accuracy is improved.

The FB is good for only one thing: the written. For practical flying it is a rubber crutch.

Bob Gardner

Thanks! I'll take a look at the skew-t charts for the airports in the course to destination field. I think that may be more accurate then the FB winds.

 

[Hang 4]

This works well for point forecasts at SFC, 3K and 6K. Slide the map to where you can see your route of flight and if you click on the barb it gives you the exact direction and velocity. It also gives a nice visual of how the wind will change over time. There's a slider to move forward in time.

Having said all that, it's only as accurate as the underlying model. In this case RAP.

https://www.aviationweather.gov/gfa

 

[AggieMike88]

Thanks! I'll take a look at the skew-t charts for the airports in the course to destination field. I think that may be more accurate then the FB winds.

This will be a good start for anyone wanting to understand the mysteries that is the Skew-T