Reported wind and gusts wrong

[markdj]

Wind reporting for weather stations is in error. I haven't scanned every weather station but I am taking the Republic of Ireland weather stations as their data is easily accessible.

e.g. Mace Head, West coast of Ireland.

The official data from Met Eireann is available as a csv file as "Yesterday's Weather"

Time Wind knots Wind Gust Knots
00:00 26 36
01:00 29 37
02:00 32 44
03:00 32 45
04:00 32 45
05:00 37 50
06:00 42 57
07:00 44 64
08:00 45 63
09:00 43 57
10:00 37 53
11:00 34 50
12:00 34 50
13:00 37 57
14:00 36 56
15:00 30 46
16:00 36 48
17:00 37 53
18:00 37 51
19:00 43 56
20:00 37 57
21:00 45 64
22:00 46 59
23:00 48 59

As you can see at 07:00, the wind was 44-64 knots. Windy reported the wind as 34-44.7 knots, and the errors continued everywhere I looked. That is a BIG problem.

I sure hope you can fix this, as this is crucial if you are wanting to have community/personal weather stations included too.

[Gkikas LGPZ]

@markdj
Reported wind speed from Met Eireann differ from reported wind speed in Windy
(shown if you press the wind sock symbol) ?

OR

do you mean reported data are different than forecasted data?

[markdj]

The reported data is different to the met Eirann reported data.

I'm noticing that windfinder is wrong too so the data source must be the issue.

[idefix37]

@markdj
That’s really weird because on Windy I see only Reported wind.
You said « Windy reported the wind as 34-44.7 knots ». So where did you find Reported gust at 44.7kt ?

On MACE HEAD, on Windy, there are no gusts in the meteo observations, only wind:

As explained by @Gkikas-LGPZ, what you see in the weather picker are just forecasted figures.

[markdj]

I'm aware the weather picker is for forecasts.

I'm just going by the 2 speeds shown in the graph (not forecast section). There are 2 speeds shown one on top of each other. Isn't that wind speed and gust?

[Gkikas LGPZ]

@markdj

[markdj]

Oh, that is confusing. The website showed it was forecast to the right of the current time and reported to the left but I'm not seeing the same interface as you.

So then the main issue now seems to be that there is no reported wind gusts.

[Gkikas LGPZ]

@markdj
Reported wind gusts are shown.
Forecasted, no.

[idefix37]

@Gkikas-LGPZ
@markdj

Yes, on Windy, some Weather Stations show reported gusts, some show only wind.
Concerning precisely MACE HEAD weather station there is no reported gusts shown by Windy.
The interface you should see is this one:

In the other case, it should be interesting that you post here a screenshot of what you see.

I have compared the reported wind, temperature and pressure at MACE HEAD WS at 8:00. The figures are the same, except for wind :
9kt for 10kt reported on Windy.... due to rounding?

[Gkikas LGPZ]

@idefix37
Wind gusts are not reported all the time from observing meteo. stations.
There are some interational criteria for that,
but also there are national deviations from the global regulations.

For aviation purposes, wind gust is reported when the value is ten knots or more
from the average.
Thus, for wind 12 kts with gusts 21 kts , gusts not reported.
for wind 12 kts with gusts 22 kts (or more) , gusts reported.

[Gkikas LGPZ]

@idefix37
Yes. 10kt instead 9 kt is due to rounding.

My explanation:

Mace head is not an airport, reporting in METAR format (wind in Kts).
It reports in SYNOP format https://en.wikipedia.org/wiki/SYNOP
and reports wind speed in m/sec

I read the 08Z SYNOP from Mace head and it is
03963 45764 /2405 10077 20053 30208 40237 52020 85/// ......

the code /2405 means wind from 240 degrees at 5m/sec.
Aprox. 1m/sec=2kts, so 5m/s=10kt

[idefix37]

@Gkikas-LGPZ

That confirms my thought, by rounding the calculation to transform m/s to kt.
The subject of this topic was « Reported wind (and gusts) wrong ». I shall check again if Reported wind is so different on Windy and on Met Eireann as said @markdj. Gusts... we know that we can forget them in this comparison.

[markdj]

Thank you for your replies. I see there is a new interface and a new Windy app update came to me this morning that shows gusts for a few stations, but not for Mace Head and others. I think it would be great if wind gusts could be included even if there is a less than 10 knot difference as for mariners, I feel this makes a difference in sea state and it is just nice to see a maximum wind gust in the 60 knot range as it was on Friday morning.

Thanks for your help, I'll be checking out this new interface today.

[idefix37]

@markdj said in [Reported wind and gusts wrong]

I think it would be great if wind gusts could be included even if there is a less than 10 knot difference as for mariners, I feel this makes a difference in sea state

Gusts are not considered to have an effect on sea state, as the avg. wind is doing.
In their inshore advisories the MetOffice do not give any gust forecast. In same type of advisories, Meteo France mention only gusts exceeding the wind from 10kt.
Gusts + 10kt to +15kt
Strong gusts +15kt to +25kt
Violent gusts +25kt
Gusts are important information for sail dinghies and light sail cruisers.
For the sea state you can take into account the wind force, only (average wind/10min.), in official marine advisories and additionally with the Wind layer on Windy.
But gust forecast is an important information on the land for the risks of damages they do.

[markdj]

yeah, I was thinking specifically about sailing yachts where a gust could blow out a spinnaker etc.