How come windy shows very different forecasts then other websites for the same forecast model
-
I see major differences between windy.app forecasts and windgur/windy.com forecasts for the same model, same forecast run, same spot. As an example, this is the current Arome forecast for "Wijk aan Zee Noordpier":
Windguru has this forecast for the same spot:
Look at the major differences early evening. It may not be the exact same lat/lon, but when viewing on a map the whole region around the pier shows 20 knots at 19:00 on windy.app, while on windguru (and other sites like windy.com) the arome-1.3 forecast for that area shows less then 10 knots. Windy claims it's forecast is from 1 hour ago (would be around 16:00 local Dutch time). I don't think there's an Arome-1.3 run at that time, so maybe it's when windy updates it's data from the last available run. But I've checked multiple times since this morning, and seen roughly the same forecast for early evening all day under Arome. Windguru's Arome-1.3 forecast is last updated 12:52, also showed roughly the same data all day.
Why is there a difference? It looks like windy.app is in error here, as other websites I've checked are perfectly aligned on the Arome-1.3 forecasts. Or do I misunderstand something?
I see the same discrepencies with other forecast models, like ICON-D2 (assuming it's called ICON-2.2 elsewhere).
-
This post is deleted! -
@gjdev said in How come windy shows very different forecasts then other websites for the same forecast model:
Why is there a difference? It looks like windy.app is in error here, as other websites I've checked are perfectly aligned on the Arome-1.3 forecasts.
I suggest you ask windy.app why.
And for any comparison you need to be sure that the data comes from the same run
Then the way the data at grid points is interpolated can introduce some discrepancies. -
@idefix37 Yeah I've send them an email. This is a lot more than interpolation differences. If it comes from the same run is hard to say, because windy.app update times don't align with model runs afaik. But the highlighted difference was there for multiple runs. Same today, where a big storm (50+ knots average wind) is hitting the west coast this morning. Correctly shown by multiple other websites that visualize Arome-1.3. But windy.app has it topping out at 29 knots average in the Arome model forecast.
-
@gjdev
As you are aware, for comparison of any predictions, it is important to check the model run reference:
-
@idefix37 And where in windy.app can I find this info? I know for windguru. But in windy.app I only find a last updated time, which does not correlate with Arome runs.
I'm pretty sure that my observation that windy shows distinctly different data for Arome is happening for the same runs, as the example I posted here, and another example I emailed to windy is pretty consistent on windy.app across different "last update" time forecasts for that model on windy.app. (The forecasts on windy.app and windgur where pretty stable all day, just different).
-
@gjdev
I’ve never been looking at windy.app
