Which weather app?

PaulGS

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So, I have Met Office and the free Windy - but I'd be happy to pay a subscription if I thought there'd be enough benefit. What do people using here in UK particularly?
 

wingcommander

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Met office and Xc weather app . Freebie. As accurate as any up to three or four days. Personally can't see the point of any paid Apps . Their basically all using same source info just different interpretation.
Short range i just look out the window. Lol
 

dunedin

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Met office and Xc weather app . Freebie. As accurate as any up to three or four days. Personally can't see the point of any paid Apps . Their basically all using same source info just different interpretation.
Short range i just look out the window. Lol
Certainly the important thing is not the “app” but the weather models used. And MetOffice (their own model) and XC (use GFS) are a decent combination - particularly if add Inshore Waters which seems to be a different view from Met Office.

But the benefit of an app like Predict Wind is being able to compare 4 or more weather models (including ECM and SPIRE). They definitely DO NOT always give the same information - I have seen forecasts for next day (ie within 24 hours) with differences of peak gusts on one model 4 knots and another 32 knots. If all models align, that means the forecast is fairly reliable (even if bad news) - if models differ be warned to expect the unexpected.
 

RunAgroundHard

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I subscribe to Predict Wind. Works well for me. I like the table format with the different models and colours for wind strength which easily lets you compare which models have similar predictions.
 

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We have paid for Windy and free Predict Wind - there is a slightly longer range and a few extras (swell etc) on the paid for Windy and its dirt cheap. That's combined with the Met Office free app and Xc

Out at sea Windy is great - close to shore the UKV (met office) 2Km forecast is better than most for coastal effects but frankly last year was so weird we may as well have looked at goat entrails !
 

franksingleton

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So, I have Met Office and the free Windy - but I'd be happy to pay a subscription if I thought there'd be enough benefit. What do people using here in UK particularly?
You do not say what you want to use the forecast for.

If it is “weather”, ie cloud and rain, you cannot beat the Met Office app. It is the output from their hires model and uses the highest res data possible as input, ie radar and satellite. No commercial app uses those data. No commercial app will update hourly. I have been using the Met Office app a great deal recently and have found that it has been uncannily accurate for such important questions as “will I need an umbrella for the next 4 hours. Even 2 or 3 days ahead, it has been good.

For the same reasons, in France, I would be using AROME, in Germany, ICON-DE, in the USA, HRRR. These cannot be beaten. All are free.

The Met Office app has a “movie” showing the expected pressure pattern changes over the next 5 days.


For cruising purposes, I make more use of the GFS because it gives forecasts out to 10 days. Actually, 15 but beyond 10, it is not very useful. I look at it at least every day. I look to see how consistent are forecasts from one day to the next. If I see that at, say 5 or 6 days ahead, they are consistent then I can plan ahead with some confidence. On occasion, we have identified windows for passages up to 7 days ahead.

Comparing forecasts from different source, say, ECMWF, DWD, CMC etc is not very useful. In effect, you are looking at a small ensemble. To see what that means take a look at the Ensemble page of Meteociel. Windy.com has a comparison facility that includes ECMWF, GFS plus one or two regional models. Usually, each model results are within the uncertainty range of the others. The comparisons may be reassuring but can be misleading. Models use the same physical equations, all have access to the same data. All are ubject to some random uncertainty.

The GFS is free, others such as ICON are free. There is no good reason to pay. You will not do any better. You may prefer presentation and delivery methods. Some commercial services make untenable claims. One makes untruthful statements about data input.

None tells you that all models include smoothing in their calculations. The Effective Resolution of any model is about 5 x the grid length used in the models.
 

franksingleton

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Windy is worth premium for me just for the distance & planning option. Plus has the 9Km ECMWF model, not sure if anyone does that for free.

View attachment 174953
You can’t get ECMWF using Saildocs free email service
  • 0 to 144 hours at 3-hourly intervals
  • 144 to 240 hors at 6-hourly intervals
Availability at about 0800 and 2000. You should get it a little earlier on paid for services but not before 0700 and 1900.
 

GHA

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You can’t get ECMWF using Saildocs free email service
  • 0 to 144 hours at 3-hourly intervals
  • 144 to 240 hors at 6-hourly intervals
Availability at about 0800 and 2000. You should get it a little earlier on paid for services but not before 0700 and 1900.
(take it you mean 'can' get)
Thnx. Says 0.4Deg in Opencpn, is that the 9Km model windy does? Just tried it in opencpn, seems limited with just wind & pressure, no gusts.
I find everywhere is different & it pays to watch the various models to see which one is consistently most useful but here in the canaries the ecmwf 9km from windy even without graphing the data does seem well ahead of the others in getting closer to the local effects round the leeward side of islands.
 

franksingleton

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You can’t get ECMWF using Saildocs free email service
  • 0 to 144 hours at 3-hourly intervals
  • 144 to 240 hors at 6-hourly intervals
Availability at about 0800 and 2000. You should get it a little earlier on paid for services but not before 0700 and 1900.
I should have said that Saildocs ECMWF output is a 0.4 degree res. However, noting that the model effective res is 0,5 degrees, there is little loss of information compared to, say Windy.com. In fact, we do not know what is the output res of Windy nor other models. Using XyGrib you can see data ONLY at the grid points issued by the originator. I have not seen that on other apps. They all interpolate so giving a false sense of resolution.
 

franksingleton

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(take it you mean 'can' get)
Yes, I really meant “should be able to”
Thnx. Says 0.4Deg in Opencpn, is that the 9Km model windy does? Just tried it in opencpn, seems limited with just wind & pressure, no gusts.
Free versions of ECMWF are limited. Saildocs only gives wind, MSLP, temperature. Plus, for those living in the past, 500hPa height.
I find everywhere is different & it pays to watch the various models to see which one is consistently most useful but here in the canaries the ecmwf 9km from windy even without graphing the data does seem well ahead of the others in getting closer to the local effects round the leeward side of islands.
ECMWF is a little more detailed than other models. Partly, that it is because it runs 2 hours later (only twice daily) than other models. It can analyse more data. The slight gain in performance is offset by the timing and the more frequent updates of GFS/UK/ICON etc. looking at the Windy comparison, I rarely find significant differences up to 5 days. When I do, I treat all models with th same caution.
I think that you would have to do a lot of objective testing to get any meaningful statistical significant differences between models. It is all too easy to forget that the atmosphere is far from precise. You cannot really define what the wind is going to be for any instant or at any location. It varies constantly.
I know that I am an old cynic about claims made by some providers of forecasts. Some statements are nonsense because they are trying to separate you from your money.
 

GHA

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I should have said that Saildocs ECMWF output is a 0.4 degree res. However, noting that the model effective res is 0,5 degrees, there is little loss of information compared to, say Windy.com. In fact, we do not know what is the output res of Windy nor other models. Using XyGrib you can see data ONLY at the grid points issued by the originator. I have not seen that on other apps. They all interpolate so giving a false sense of resolution.
The windy 9Km ecmwf does seem to usually be very good at picking up the afternoon onshore winds which pick up over about a 15Nm southern coast here in Gran Canaria which presumably would be missing from the 0.4Deg model.
And agree with XYgrib display resolution, so easy to kid yourself, just read any weather app thread on here. 😁
Randall Reeves said it well, weather forecasts might not be right all the time but they can be strongly suggestive 🤣
 

GHA

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Found this again recently which I made a while ago with some python code, met office actual wind and met office forecasts for a calibrated wind senor @ 10m on one of the Scillies, amazing the forecasts are usually as accurate as they are!!

1712224805809.png
 

franksingleton

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The windy 9Km ecmwf does seem to usually be very good at picking up the afternoon onshore winds which pick up over about a 15Nm southern coast here in Gran Canaria which presumably would be missing from the 0.4Deg model.
And agree with XYgrib display resolution, so easy to kid yourself, just read any weather app thread on here. 😁
Randall Reeves said it well, weather forecasts might not be right all the time but they can be strongly suggestive 🤣
As ECMWF Effective resolution is 0.5 degrees that is difficult to explain. From La Rochelle northward or, at least north of Ile d’Yeu we often found that the GFS got the sea breeze effect well. UKV can get the Solent sea breezes but may not/
 

Bristolfashion

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Predict wind (paid) for the tables & range of models

Windy (free) for the representation of systems

Met office inshore waters

BBC weather for on land forecast
 

franksingleton

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Found this again recently which I made a while ago with some python code, met office actual wind and met office forecasts for a calibrated wind senor @ 10m on one of the Scillies, amazing the forecasts are usually as accurate as they are!!

View attachment 174976
I assume that is UKV? Pretty good. It is similar to my use of the Met O app for rain. Someone might like to show this to Viago, Zoidberg and some others who were spouting nonsense in another, recent thread.
 
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