Users of Windy: why do you want historical weather data?



  • @johnckealy
    Actual observation would be better for me. You are correct about surface analysis. That is also a very big part of what I am looking for. High pressure, Low pressures, approaching fronts and receding fronts are always great information.



  • @johnckealy
    I forgot to mention, I hope that one day you guys would look at competing with XMWeather. I purchase XM weather to get it on my Garmin chart plotter and it's okay but no where close to as good as what Windy.com provides.



  • @johnckealy,
    I want historical data to help me search for the best time of year to plan a kiteboarding excursion.



  • ...and to reflect on previous sessions' recorded wind speed and atmospheric pressure.



  • Thanks for the response @4kiting, that's an interesting one too. I like to kiteboard as well and I know how finicky the weather can be when you're looking for the right conditions! It sounds again like a surface analysis is what you want? But perhaps a surface analysis that contains more details, and maybe even spot observations/satellite data mixed in.

    @rfleming I should mention, when you say "you guys", I don't work at Windy. I'm just a fellow weather enthusiast :) I had a look at XMWeather though, seems to be mainly satellite data that they do?

    I really think there's some potential here for a new way of looking at surface analysis... I'm starting to get the feeling that a big question many people might be asking, when they look for historical data, is: When I look at a pattern in the windy forecast that I've seen before, what does that really mean for me?

    I'd love to hear any other opinions.



  • John,
    I just discovered Windy yesterday, so I'm trying to discover which model has the more accurate forecast for mid-day winds at my location (Northern Virginia). This is a one-time need that requires both model data and observation data. But only for one recent month. So an archive going back two months would cover me. I would not be doing a big full-year comparison. For that, I'll just use Windy going forward and see how well it predicts my winds.
    Steve



  • I hope my request counts, for it is strictly for sentimental reasons..... 😊
    During a couple of very brisk spring days and nights early 2018, I undertook the transfer of my very first sailboat.
    As I was a completely novice sailor I had not heard of Windy and so, with only the most basic weather info, I started the maiden voyage. Little did I know that I was going to be in for much more than I had asked for!
    I have records of the GPS path sailed, but none of the wind conditions. It would mean a lot to be able to see those weather data....
    Cheers.



  • Hey @StephenBeste, welcome to the world of Windy! Ivo and the team have really created something special here. So, as others have mentioned, the "historical" data you need doesn't go back especially far... And it sounds like you want to understand model performance for your specific location. There's a technique called Model Output Statistics (MOS) that deals with this. Although model verification is a whole science in itself, I've also been interested lately in the idea of creating something like that on a more basic level. Maybe I'll look into it again...

    @Franzus-0, of course your post counts! Do bear in mind though, this is merely a discussion; I must reiterate that I don't work for Windy, and I'm not collecting "requests" as such! Congrats on the new vessel, and glad you found your way in the end :) As I understand it, that was one of Ivo's main motivations for Windy; that everyone could have access to the best data possible for free. I was blown away when I saw that they had the full 9km ECMWF fields on discovering Windy; I found myself asking around about Windy at the next ECMWF workshop I was at :) As to the historical data, you seem to be looking for something similar to @rfleming – essentially a type of analysis chart.

    Some kind of MOS-based analysis charts that go back a few months, perhaps with some satellite and MADIS data mixed in.... this might have to be my next project :) Thank you so much all for your input. Please keep the discussion going if you have any other perspectives on historical data!



  • @johnckeal Hi I've just registered as a member with Windy and my interest in historical weather data is for fire weather. Cheers Mel



  • Hey @Coop4433, welcome to the community! Fire weather sounds badass; can you be more specific? I assume you'd be interested in winds at multiple model levels, and maybe some particle dispersion models. Model history of CO2, air quality, aerosol... that sort of thing? Observations?



  • @johnckealy said in Users of Windy: why do you want historical weather data?:

    some

    I would love to have access to historical weather data for aviation purposes.

    I work for a charter airline that operates to destinations all over the world. We would love to have this data regarding averages for a given month. This is crucial when trying to figure out our Take-Off and Landing performance for future operations.

    Whats the average high for a given month or week for a specific time during the year? What are the average winds during a specific time of day? Do we need to add a stop somewhere because recent annual trends show its going to be too warm? Or can we make a specific nonstop route because its trending cooler?

    Some websites try to provide this data...most seem inconsistent. However, we would love to see this information come from Windy.



  • Hi @garlandz, thanks for the comments. It's a little unclear what you mean. Sounds like you're talking about a climatology, are you not? The "average high" (do you mean temperature?) over a week would be quite different to that of a month, or for a certain month across many years. What are "recent annual trends"? Is that a reference to climate change? Can you give an example of a website that tries to do it? Are you speaking to purely observational data (at airfields), or is there a model component (remember that Windy are primarily focused on model visualization)?



  • @johnckealy said in Users of Windy: why do you want historical weather data?:

    Hello. Yes climatology would be the correct term I am looking for. I would love for Windy to have "average highs and lows" data built in for airfields, especially under ICAO codes. Would be extremely helpful! Right now we take data off of Meteoblue. But I would like to have more accurate data taken from the history of METAR reports if it is possible.

    I guess what I am looking for overall is a history of purely observational data to reference at certain airfields built into windy.

    Thanks for your time.



  • Ah well here's a coincidence @garlandz; looks like the guys at Windy just added this!
    https://community.windy.com/topic/8710/windy-predicts-extreme-wind-temperature-and-rain



  • @johnckealy

    The new future is great! Thanks for the quick responses. I look forward to windy becoming better and better everyday.

    Best Regards,



  • @garlandz I feel I should mention again (third time this thread!) – I don't work for Windy! This thread is a discussion between users :)



  • @johnckealy hot air baloonist and GA flyer here - my reasons and use for historical data:

    (1) assume I do a flight and some meteorological situation crops up which I did was not aware of/did not look at

    (2) assume some flight accident happened. The press typically reports sensationalistic nonsense like so: https://www.austrianwings.info/2019/06/heissluftballon-in-kilb-abgestuerzt/ . And a proper accident investigation takes forever, und you might not hear of the results. The national ATC organisations arent much better - they typically delete forecasts right away - no going back.

    In both cases I would like to go back in time, and see myself if I could have avoided the situation - basically for my learning, and to answer questions of concerned people.

    Both use cases involve a time window of a few days max. Two days would already be great!

    Personally I have no use for historical data going back further in time.



  • Thanks for the comments @mhaberler. You've hit on an important concept here. Is there such a thing as a "historical weather forecast"? You seems to be alluding to model data. The important question is this – could you have avoided a dangerous situation if you had looked at the forecast an hour before flying vs. 3 days before flying? Which model run is the one to reference?

    We've talked about creating more detailed surface analyses before. But with an investigation, for example, you would need to know what forecast data you had available at the time (and what's its lead time was). Not only that, but which model. Weather forecast models are an extremely fluid thing, and are just a tool. This is why, when stakes are high, companies shell out for private forecasting companies who employ real forecasters. And with a proper accident investigation, it's usually time to do that. I can't speak to other modelling centres, but I know the UK Met Office archive all their UM forecasts (which cost an obscene amount in storage), so that they can be referenced later.

    But, if we're just taking about your own learning, it sounds like a surface analysis would do the job nicely. Surface analyses are traditionally just synoptic charts (isobars and fronts), but I think we can do better. I may just start working on something like that myself (though with one year left, I should probably make a stab at starting to write my PhD thesis).

    Let me ask you this @mhaberler, what level of detail would you need to "see if you could have avoided a situation"? Highs and lows? Surface winds? Gusts? Winds at all levels? Precipitation? Visibility? As gridded data or just at airfields? I have some aviation forecasting experience, but we were very focused on just our own airfields, and the WAFC/LOLAN guys used to take care of the rest.



  • @johnckealy said in Users of Windy: why do you want historical weather data?:

    Thanks for the comments @mhaberler. You've hit on an important concept here. Is there such a thing as a "historical weather forecast"? You seems to be alluding to model data. The important question is this – could you have avoided a dangerous situation if you had looked at the forecast an hour before flying vs. 3 days before flying? Which model run is the one to reference?

    that is the secondary goal

    First, I would love our wonderful and super-expensive ATC corporations would provide their forecasts not just from today onwards, but a couple of days back. Just what they publish on their aviation briefing website. That would cover 90% of my learning needs. Could I have avoided that situation if I had read the aviation briefing more diligently? Note: no historical 'data', no fancy UI and yadayada - JUST their briefs. So wrong forum here.

    the other 10% of my needs would be going back in time for a few days max and look for stuff which was NOT in the aviation briefs. For instance, the accident linked above was due to a cold are pressure wave within the inversion layer, and it was NOT in the aviation briefs.

    Let me ask you this @mhaberler, what level of detail would you need to "see if you could have avoided a situation"? Highs and lows? Surface winds? Gusts? Winds at all levels? Precipitation? Visibility? As gridded data or just at airfields? I have some aviation forecasting experience, but we were very focused on just our own airfields, and the WAFC/LOLAN guys used to take care of the rest.

    I know.. the aviation weather forecasts are of so-so for ballooning and of moderate value at best if you do long-distance/high altitude. Example: predicting northerly föhn a few days ahead - in reality you get hints for föhn-affected terminal areas like Innsbruck and not much beyond.

    For a short-range check a few hours before a pedestrian flight I mostly do precipitation, visibility, clouds/fog, average wind, wind gusts, shears. An important value for us is winds/gusts in the planned landing area, and here forecasts outside of large airports scarce and unreliable - we replace that by webcam views (sometimes you can judge wind that way), private weather stations, and experience about typical valley wind systems.

    for long-distance over mountains a lot more is involved - vertical profiles, soundings, wave prediction, sometimes even likelyhood of a hydraulic jump. For longer-term prediction Rossby waves in the FL180 Geopotential forecast help - black line cutting the Alps N/S is a good predictor a few days out. As the flight comes closer, you look at the more local phenomena - ground wind etc like for a pedestrian flight.



  • Nice one @mhaberler, sounds like you know your stuff! The Föhn effect is a really tricky beast to forecast; actually, pretty much all mountain-based phenomena in general are a nightmare to get right. As people rely more and more on the models, the forecasters who can actually understand and predict this stuff become a dying breed... But that's a general thing, and for the marjoity of these phenomena, it's only the pilot that will ever see it, not the weather models, and not the observations network. So historical data wouldn't be much help anyway right? But then again, the charts can certainly show you the right conditions for these things to form. If pilots had a medium to add in local scale phenomena that they saw on a flight to a historical chart, that would be pretty cool. That way, they could reference what they saw when that setup reoccurs. I'm getting more and more interested in creating this myself...

    By the way, with the aviation briefs, what's the "aviation briefing website"? Could you give me a link? Also, I just spent some time on working on my skewT platform tephigrams.org over the weekend, some vertical profiles, if it helps at all.


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