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Old June 8th, 2011, 03:41 PM   #1
Chock Norris GeorgeC is online now
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wind/temp interpolation near surface

During ground school, I was taught to use the standard lapse rate to interpolate temps aloft. Since temps are not given for 3000', is it better to interpolate between the surface temperature and the 6000' temperature, or interpolate down from 6000' using the lapse rate? I'm interested to know the justification behind the answer.

Similarly, for altitudes below 3000', is it reasonable to interpolate between the wind vector given by the winds aloft forecast, and the surface wind given by the relevant TAF? I notice that foreflight does not account for winds aloft for low altitudes (say, 2000'); why is this so?
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Old June 8th, 2011, 03:47 PM   #2
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Re: wind/temp interpolation near surface

a better guesstimate of temps aloft would come from winds aloft forecast or forecast soundings (http://rucsoundings.noaa.gov). there are often inversions and other atmospheric fun stuff that blows the standard lapse rate apart.
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Old June 8th, 2011, 07:27 PM   #3
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Re: wind/temp interpolation near surface

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Originally Posted by scottd View Post
I've said this many times, but if I were King, I'd retire the Winds/Temps aloft product. There's way too many other forecast products that have a better temporal and spatial resolution.
Please provide several examples of those "other forecast products to the lazy and technologically inept/deficient.
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Old June 8th, 2011, 09:24 PM   #4
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Re: wind/temp interpolation near surface

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Now, I can't give away all of my secrets. Come to my live workshop and I'll show you in person!
To "lazy and technologically inept/deficient" I should add
"financially strapped or otherwise reluctant to spend drinking funds on things other than drinking".

Will there be a no host bar at your live workshops?
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Old June 9th, 2011, 07:57 AM   #5
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Re: wind/temp interpolation near surface

Thanks, Scott. I actually happened upon rucsoundings and your article last week. I suppose there's no need to interpolate if higher resolution data are available to begin with...
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Old June 9th, 2011, 12:38 PM   #6
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Re: wind/temp interpolation near surface

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Thanks, Scott. I actually happened upon rucsoundings and your article last week. I suppose there's no need to interpolate if higher resolution data are available to begin with...
If your only concern is wind direction and velocity, and you know how to access a Skew-T chart, click on the "Get text" button at the bottom for a neat printout that requires no interpolation. The altitudes are pressure altitudes, though, so if you are anal enough you can convert to msl.

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