Wrong wind data

[vojkob]

Hi
Can anybody explain why windy miss All wind speeds in ionian? Every day i moyice agsin failures in winds speed of 100 percent.really anoying

[Gkikas LGPZ]

@vojkob
Why do you think that windy miss all wind speeds in Ionian?
I compare observed data (e.g. from meteo. stations in the coast) with forecast data
and I don't see any great difference.

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[Gkikas LGPZ]

.......
today (13 July) ECMWF gives 5 max 6 BFT.

with gusts up to 8 BFT in the Otranto strait

For tomorrow the forecast is for 3~4 BFT.

In what area you observed 100% failure?

[vojkob]

We are in euffemia kefalonija, windy shows 8 knots wind, instead is 35knots

I have same experience begore. Data are not precise enouvh to be usefull

[Gkikas LGPZ]

@vojkob
Thank you for providing the location where you observed such a big difference
between reported and forecasted wind speed.

The phenomenon you report is called "wind funnelling effect".

Agia Effimia (Keffalonia, Greece) is located in the south of narrow valley.

Steep mountains, 900m high, rise in the north and south of the valley
with peaks only 2 milles away from each other.
These days, the NW wind is funnelled, especially during the afternoon,
resulting gusty northwesterlies.
Light winds can often become much stronger when they are forced
to converge and funnel through a narrow mountain pass.
Unfortunatelly, a weather model with a 9 km resolution is unable
to accurately depict the topography around the valley,
and therefore will not accurately model the winds at Agia Effimia.
Only human forecaster with knowledge of the local topography,
as well as historical knowledge of how the land affects the wind in the area,
can therefore predict the NW'ly wind at Agia Effimia with accuracy.

[Gkikas LGPZ]

....
Following images show how a weather model with a finer grid,
gives better forecasts in such conditions.

But, for even better forecasts in such a complex terrain,
high resolution (grid=1 km) weather models needed.