Forecast period representing the wind gust value in ECMWF meteogram

stitch

Windy team developers, can you provide the 10m wind gust field used in the meteogram window for the ECMWF model? Is it 1/ instantaneous wind gusts, 2/ 10m wind gusts in the last 3 hrs, or 3/ 10m wind gusts in the last 6hrs?

Looking at the above example, the wind speed and gust speed at say 12pm onwards (through the afternoon) is not sensible. 4-7km/h mean wind speed and 20-35km/hr gust speeds. And I am familiar with this location and likely winds.

Would I be correct in saying the wind gust forecast is taken over the previous 6hrs, maybe 3hrs?

Thanks.

idefix37

@stitch
In the FAQ it is said to be during the last 3 hours.
https://community.windy.com/topic/3361/description-of-weather-overlays?sort=oldest_to_newest

Gkikas LGPZ

@idefix37
FAQ was written years ago when windy provided only 3hr forecast data.
Now, we have 1hr time resolution so clarification needed.

idefix37

@Gkikas-LGPZ
Yes, same with rainfall which is said to have occurred in the last 3 hours. This is confusing in the 1-hour meteograms.

idefix37

@Suty
Please could you clarify the question about the wind speed, gusts speed and rain amounts in the 1-hour meteograms. Are they predicted for the last 3 hours or for the last hour?
It seems that for rain it is quite obvious: forecast for the last 3 hours on the weather picker and 1 hour in the 1-hour meteogram.

Is it the same for wind and gusts?

Suty

@idefix37 Hi there, as you said rain in the picker is displayed as a sum of 3 hours, but beteogram in general shows all values in 1h step and it is not anyhow interpolated from 3 hours.

stitch

@Suty

Are the meteogram images generated in-house or are they sourced through ECMWF or another party? If in-house, are you able to seek which ECMWF gust field code is used for the Meteogram display?

From the ECMWF HiRes 10-day dataset:
10fg6 (10m gust in last 6hrs),
10g (10m gust in since previous post-processing),
10fg3 (10m gust in last 3hrs),
and i10g (instantaneous 10m gust).

There are a few options available. I use the EC gust as a forecasting parameter and would like to get confirmation as to the gust sampling time.

Thanks.

Filip_K

Hi @stitch, we're using 10fg3 for forecast hours 0-144 and 10fg6 from forecast hour 150 further. That is how these parameters are available. Values for 1h step are linear interpolation of those 3h or 6h values.

idefix37

@Filip_K
Hi,
For Wind, are 1 hour step forecasts also interpolated ?
But not for Rain?

stitch

@Filip_K thank you

Filip_K

@idefix37

For Wind, are 1 hour step forecasts also interpolated ?
But not for Rain?

For ECMWF-HRES, only gusts need to be interpolated because they are available only every 3 or 6 hours. Precipitation is available every hour.

idefix37

@Filip_K
Thanks you, and same for Wind, ECMWF provide hourly forecasts ?

Filip_K

@idefix37
yes, every other parameter is available for each hour