Saturday, October 17, 2020

Unreal Weather - Live METAR FAQ

Q: What is this mod all about?

A: The Unreal Weather - Live METAR mod simulates the real weather within Microsoft Flight Simulator 2020, using up-to-date METeorological Aerodrome Reports, a.k.a. METAR. It provides a free alternative to the built-in "Live" weather within the game.


Q: How is the weather simulated by the mod different from the "Live" weather in MSFS 2020?

A: While the Unreal Weather - Live METAR mod uses the current METAR reports to simulate the weather, the in-game "Live" weather utilizes the weather reporting and prediction services provided by MeteoBlue, plus some artificial intelligence on top of that. In addition, the "Live" weather utilizes the internal weather simulation means in full capacity, while the mod is currently limited to the data model available in the Weather Settings menu. It, for example, cannot recreate different "zones" around the player, so the weather will always appear uniform.

Also, this mod is a work in progress, which means that it is being constantly improved, often accommodating the feedback from its users. 


Q: How do weather transitions work?

A: There is a separate post dedicated just to that topic alone:

About Weather Transitions and How They Work


Q: What about snow cover?

A: Unlike all other weather condition indicators, the ground snow coverage is not reported in METARs. There are some specific indicators that you may encounter, such as 4/nnn or SOG, but those are typically related to runway conditions, and not surrounding areas. The mod honors these indicators, but they are rare.

In addition, the mod will generate snow coverage when the current METAR indicates that it is snowing. This feature is controlled by the following flag in the mod's settings:

enable_snow_cover_from_precipitation: 1

The above approach will not address all possible scenarios, obviously, especially when the weather is clear. If you fly over the areas that should definitely have snow cover, but the corresponding METARs prove to be unhelpful, you may want to set the snow cover value manually, using the corresponding slider in the Weather Settings panel. In order to do that, disable the corresponding feature in the mod's settings by changing the flag's value to 0 and restart the Sim:

enable_snow_cover: 0

That will ensure that the mod will not attempt to adjust the Snow Cover value on its own, enabling you to use the slider as you wish.

Q: I've installed the mod and added my API token to it, but the mod does not work.

A: Here is how to troubleshoot this issue:

  • Shutdown the sim and remove the existing copy of the mod from your Community folder.
  • Deploy a fresh copy of the mod from the ZIP file, but do NOT modify the mod settings or add your API token to it just yet, i.e., leave it "as is."
  • Start the sim, make sure it works and the mod is operational: your World Map screen should work, and the weather presets list should now have the "Unreal Weather - Live METAR" choice.
  • Start flying and make sure that you select "Unreal Weather - Live METAR" in the weather presets list. At this point you should see the "Missing API token; check settings" error in your Weather Settings panel, just underneath the Pressure MSL slider.
  • If you got this far, the mod is working.
  • Now, shutdown the sim and add your API token to the WeatherEditionMenu.js file in the deployed copy of the mod in your Community folder. Save the file.
  • Start the sim. Your World Map screen should still be complete, without any missing buttons. (If it looks incomplete, that would mean that you've damaged the JS file while making changes to it.)
  • Start flying; the mod should be working and the METAR information should be displayed in Weather Settings.

Q: I've just installed the mod and now my in-game World Map screen is broken, some buttons are missing.

A: This would indicate that the WeatherEditionMenu.js file in the mod folder got damaged, most likely, when you were adding your API token to it or modifying the mod settings. Re-deploy the mod and start over.

Remember: You should always use a code or plain-text editor, such as Notepad, Notepad++ or similar when making changes to the JS file. Do NOT use Microsoft Word or any other editor that supports text formatting - such editors are not suitable for modifying program code.


Q: I've just made some changes to the mod settings, but the mod seems to ignore them.

A: In order for the changes to become effective, the Sim must be fully restarted. It will not pick up your changes on the fly, as it does not reload the mod files after it had loaded them initially.


Q: I am flying near my house, and the real weather outside is different!

A: METAR reports only include some data points about the local weather, but not all of them. Therefore, the mod can only simulate the real weather to a certain limit. Cloud layer thicknesses are just one example - they not part of METAR, except for cumulus clouds, so that missing information is randomized. In addition, each report only provides the weather information as observed at the station's location; some of them are created automatically, while others are supplied manually by operators. Here are some additional points:

  • Learn how to interpret the METAR data. It can be confusing at first, but soon enough you'll starting "parsing" these reports in your head easily. If certain data points are missing from, or present in the current report, there is nothing the mod can do to fix that.
  • Consider how far you live from the station that provided the report; your local weather can be different from what your closest station reports.
  • METAR reports are not always up-to-date, especially in remote areas or developing countries. Occasionally, they can be stale, i.e. the weather may appear outdated. Even if a report is only 1 hour old, the real weather may have changed since the report had been created. Again, see what is in the report, not outside your house window.
  • Make sure that you have not disabled certain features when editing the mod settings. If you have, the mod will not affect those features within the game.


Q: What about winds aloft? Does this mod support them?

A: METAR reports do not include any information about winds aloft, so the mod cannot recreate such winds in the Sim. It, however, tries to emulate randomized winds at the higher altitudes in order to provide some variety. That option can be turned on or off in the mod settings.


Q: Can winds aloft be emulated using the real-life data?

A: No, not at this point. If someone could locate a robust and free web API that would accept latitude and longitude as the arguments and provide the winds aloft data in real time, then yes, it can be done. So far, no one has located it. Paid providers collect that data in bulk from NOAA or similar sources, parse, cache and then expose it via their own custom web services on demand. This mod alone, without a similar backend, cannot do that.


Q: I found a web site that displays up-to-date wind aloft data. Can it be used by the mod to simulate such winds?

A: Unfortunately, no. Please see the answer to the precious question.


Q: I have some ideas about this mod. What should I do?

A: You can always contact me directly. See the main page of this blog for my contact details.


Q: How can I contribute to the development of the mod?

A: If you like the mod, please consider making a small donation. See the main page of this blog for the details.


Unreal Weather - Live METAR Version 1.7 Has Been Released!

Please see the main post for the details about this release: Unreal Weather - Live METAR