incorrect weather forecast and sudden lower data as exist
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the weather forecast in four days before required date announced more precise information.
In two days before required date coming the weather forecast melted.
In required date the wether forecast shows information same as four days ago.
In result the wave from 1,5m decreasing to 0,5 and again increased to 1,5m…
Wind jumped from 12m/s to 5m/s and back to 12!
something wrong with information during the last month and become difficult to plan voyages with Windy. -
Next time you see a weird forecast, at least give the location and show screenshot, otherwise what can we say ?
And remember that the forecast is not made by Windy. It is the visualisation of major global and regional weather models. If you see the forecast of a model whose update was 4 days before , that does not mean it will not change at more recent updates. -
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@Aleks-Valdes
I can't understand how your screenshots are demonstrating your issue.The 2 first ones are showing the forecast for 5:00 and 8:00 for Saturday, from apparently 12z and 00z reference time respectively (not the same model update)
And for example at 10:00 in these screenshots, the wind was predicted 10kt and 9kt respectively while the waves were 0.3m and 0.4m. Not a huge difference !The third screenshot shows the map forecast for 10:00 on Friday. For the next day, Saturday at 10:00 the wind was predicted at 13kt and waves at 0.4m. These values comes from another model update.
These small differences between different updates of the model are not incorrect !
Click the small i in bottom right corner to know what update is used.
See for information
https://community.windy.com/topic/11361/a-difference-between-reference-time-and-update-time?_=1693041429086 -
I will try to clarify:
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The voyage was planned in 26.08.2023 and according the weather was expected to be till 31.08. Vessel have limitation 0.8m for waves and 10m/s wind.
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In morning 27.08 the weather forecast showed other situation for our position.
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In evening updates 27.08 the weather become worse for our position and operation we doing.
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But if you look at weather forecast from 25.08 it seems more precise.
The question is why there is a couple of days announced in 26.08 looks good and suddenly not.
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In reality 23kt wind 27kt in gust.
Waves 1.2m -
Weather forecasts are not exact calculations. There is a part of uncertainty in the weather prediction. In Windy, forecasts are provided directly by weather models.
To have an evaluation of the uncertainty it is important to look at the forecasts of several models.
For example in the next days on your voyage location :
Why can a model vary its forecast during the period of 4 days before the deadline? It repeats the calculations 4 times a day and there is little chance that the result will be perfectly constant over 4 days. Otherwise just one calculation per day would be far enough.
In addition to Windy, at sea you must rely on official marine advisories. But they are never very precise as example:
WIND: Northwest 3 to 5 Bft, backing west or southwest 3 or 4 Bft.
SEA STATE: Slight, occasionally moderate.
WEATHER: Showers.
VISIBILITY: Good.
For this reason, it's a bit strange that you plan to sail at this distance in Baltic Sea with a boat that cannot withstand more than 20 knots of wind and 0.8 m of wave height, even if we are in the summer season. Or, is it a special service and research vessel with only inshore and restricted capabilities ? ….To investigate on the Nord Stream pipeline sabotage location where you placed a favorite location ? :) -
@Aleks-Valdes as said by @idefix37, to get a better forecast you should vary and compare the models. One of the problem here is that for each model you only get a single forecast. Nowedays, weather institutes use more and more weather model ensembles. For instance, ECMWF can calculate 21 single forecast by playing on several parameters so in place of getting a single forecast calculated from a lot observations, you will get a set of probabilities associated to a parameter you wish to know : rain, snow, wind speed,… When your time horizon is more than 4 days, model ensembles are very powerful
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Thanks all for comments.
The problem actually that there is no service like on Dogger bank to have precise weather for vessels position. As survey vessel we belong to weather condition and it is complicated situation to decide when is time to hide in port. Yes, we cannot do 20 knots and if 1.5 waves catch vessel at sea everyone will be happy )). -
@Aleks-Valdes
OK, I understand. It is difficult for you to decide when you can cast off mooring when the weather and sea conditions are close to the boat limits.
So for the wind forecast, look at the Compare table where there are several models for your area. And for waves try the 3 models available to confirm or not the prediction of the default model ECMWF. -
Velocidade do vento invertida, vermelho dando baixa velocidade e azul muito vento !!!!! Velocidade errada em todos os pontos !!!!!
Rio de Janeiro e América do Sul toda !!!!! -
@marçal-mello
You probably see this bug on Android device?
If so, this bug should be fixed in next release
https://community.windy.com/topic/28158/wind-gusts-not-working-well-at-all
