Windspeed and direction different heights

[danie]

I am not too sure how to use the wind direction/speed at different altitudes. Say for instance you take a location that is 5000' amsl and use the cursor to move the height to 6400 feet....does it mean that the altitude is 6400 feet above the 5000' elevation or does it mean 6400 feet amsl, in other words 1400 feet above ground (the 5000' location)?

[Gkikas LGPZ]

@danie
the winds aloft are amsl.
Actually (and more precisely) are the winds on standard isobaric surfaces.
For example the wind at 5000ft is actually the wind in a "surface" of the atmosphere where the pressure is 850 hPa.

Over mountains those "isobaric surfaces" may intersect* (cut) the orography (land surface).
Thus, if you point on Everest and chose wind at diferent altitudes you'll find out that wind "stays the same" at all the levels from Om (msl) up to 8.000m.
On the airgram you'll see no wind at low levels.

"*" Actually, models isobaric surfaces "touch" models land surface.

Hope the following image will help.

[ondrejspilka723]

@Gkikas-LGPZ

I see some issue with meteogram wind strength.
Look at the sample, at 2700 AMSL wind is 17m/s.
But meteogram for the spot shows 4m/s, which is for 1000hPa theoretical height (underground).

I clicked on the spot on map to get prediction for it's location and altitude.

So, in my opinion, basic meteogram, doesn't reflect altitude, so it provides highly inaccurate predictions. Especially for paragliding pilots it is super important to consider wind strength at takeoff altitude.

It is pretty tricky and the only way how to get strength for altitude is use Airgram or Wind layer at height.

I believe this shall be fixed as it leaves quite a lot of space for misleading user.

[idefix37]

@ondrejspilka723
As there is no issue, try to understand the post of @Gkikas-LGPZ above.

And this one too:
https://community.windy.com/topic/4831/aviation-winds-aloft-on-airgram/4?_=1681921025576

[ondrejspilka723]

@idefix37 well there's still an issue that model shows 4 m/s at 10m above ground while reality will be 17 m/s and more

But I understand model limitations. Hope we can agree on that.

Thanks.

[idefix37]

@ondrejspilka723
Which model are you talking about ?

[ondrejspilka723]

@idefix37 visible on printscreens, please check them...

[idefix37]

@ondrejspilka723

ECMWF has a 9km resolution, so in mountains….
In the location you show, at mountain top, it could be useful to check Airgram.
An try ICON-EU and Meteoblue.
Then if you measure wind at top of a cliff or a sharp summit weather models will never predict the right speed.