Posts made by dmn

John - I understand that reasonably well. But trust me, the forecasts are wrong. Just plain wrong. I work every day in the mountains where Windy says it will be raining, it is absolutely not raining, not even close. Perhaps the EC model is trying to be "too clever". But they are chronically wrong either way.

Tomber - Windy may not be responsible in a technical sense, but they publish a website with errors in the forecasts. So in branding and public perception, it is Windy who is wrong, not the model that windy is porting.

I like Windy, but I hit so many accuracy hurdles over the years. It is hard to commit to them. Speaking mainly in terms of Windy as a mountain snow forecasting tool.

This is a bug. I started the thread in the wrong spot, sorry.

https://community.windy.com/topic/7445/windy-ecmwf-meteograms-are-wrong-shows-rain-when-well-below-freezing

Rain and convective rain mixed with snow, at -8C in places where it is clearly snowing. It is a regular error that I have seen on your forecasts for locations around the world.

It grid problem, because GFS with a 22km grid does not show rain at all.

Either ECMWF data is unreliable/wrong, or your computers are wrong.

This is a serious forecasting error.

Please confirm if freezing level is stated as:

A) elevation above the ground at that spot

or

B) elevation above sea level.

Look at Mt Fuji in Japan, for example. It is directly next to the ocean, yet Freezing Altitude changes considerably depending on if you click on the summit, or the nearby ocean. Yet it should be the same for very similar Lat/Long location.

But those custom settings are not reflected in the bottom right scale of values. It still shows default.

@ivo said in What elevation for spot forecasts?:

@meteo-gr

Yes it is terrain elevation.

No we do not display model elevation

No we do not adjust interpolated values to its terrain height (interpolation in between two model levels). @TZ did some coding in this field but not finished it yet.

We do not have ANY METEOROLOGISTS in Windy team which is shame (the one I would love to have in team is Swiss), therefore we lack a knowledge in this field. If you have suggestions how to interpolate model's parameters to terrain height, please let us know. Send us some formulas to use or some document how to do it please.

So that I understand what you are saying, could you please confirm:

1. the elevation in "about location" of 2113m NOT the elevation for the meteogram forecast immediately to the left of that information?

2. the elevation in "about location" of 2113m refers to the elevation of the spot position on the map topography (my visual check confirms it is always pretty close)

3. the meteogram forecasts do not adjust their values for elevation of the spot position on the map?

4. the meteogram forecasts are based on a wide grid, which can result in a high peak displaying data for a low valley that falls within the same grid.

When I change the zoom level, the spot value for the selected forecasts variable changes. In this case temperature changes from +1C to -1C with a change in zoom level.

Then, the ECWMF forecast at the bottom of the screen shows -2C for the same time. I assume this meteogram forecast is for a different elevation of the spot value displayed on the map?

That is 3 different temperature forecasts for the same place at the same time. I really believe in windy.com, but this kind of thing makes it hard for me.

@ivo I have trouble posting a cogent screenshot examples because:

1. if I change the zoom level on the map, then the spot forecast value changes. This makes it impossible to compare the map Fx with the meteogram Fx.

2. if I click the spot location on a known 3000m peak, and then I change the elevation level for the forecast using the slider, I get different values for "Surface" and "3000m". Which elevation slider setting should I use for a forecast on terrain which is 3000m asl? I can find no consistent relationship. This makes it impossible to compare the map Fx with the meteogram Fx.

Any response to this?

How can I check the elevation being used for a spot forecast, the one that displays below the map? The temperatures and snowfall forecasts in the meteograms absolutely do not correspond with the precip type and temp data displayed on the map, for the corresponding point on the map. Is this due to a wide grid being used? If so, it makes the forecasts very misleading for mountainous areas.

I am not a fan of the white labels indicating the settings always being visible on the right of the screen.

Also, spot snow accumulation changes with zoom level.

Thanks, looking forward to it.

Do you plan on changing temperature with altitude in the future?