wind/temp interpolation near surface

Discussion in 'Pilot Training' started by GeorgeC, Jun 8, 2011.

  1. GeorgeC

    GeorgeC Cleared for Takeoff

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    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?
     
  2. tonycondon

    tonycondon Gastons CRO (Chief Dinner Reservation Officer)

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    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.
     
  3. Richard

    Richard Final Approach

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    Ack...city life
    Please provide several examples of those "other forecast products to the lazy and technologically inept/deficient.
     
  4. Richard

    Richard Final Approach

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    Ack...city life
    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?
     
  5. GeorgeC

    GeorgeC Cleared for Takeoff

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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...
     
  6. bobmrg

    bobmrg Pattern Altitude

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    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.

    Bob Gardner