Add Barometric Pressure to HA Weather Forecast Model

[bchastain]

Context

Several weather data providers give access to hourly or daily barometric pressure forecasts as a part of their API. I know that OpenWeatherMap and WeatherUnderground do this and there are likely others as well.

Proposal

We add a ATTR_FORECAST_PRESSURE entry to the HA Weather Forecast Model so that HA will be able to work with this readily-available pressure forecast data.

Consequences

The only issue I see is that perhaps not all weather APIs provide a forecast for pressure, so this value would be missing for those integrations.

[MartinHjelmare]

It will be easier to get approval here if we can see a summary of all our current weather platforms how many of them provides the pressure forecast.

[bchastain]

OK I can work on that, but out of curiosity, what's the downside to adding this to the model even if some platforms don't provide it?

[MartinHjelmare]

We only add features that are supported by a larger part of current and potential integrations.

[bchastain]

OK I dug through them all, and here's my summary:

Platform	Any Forecast	Current Pressure	Pressure Forecast
Accuweather	Y	Y	N
Ambient Weather Station	N	Y	N
Buienradar	Y	Y	N
DarkSky	Y	Y	Y
DWD	N**	N	N
Environment Canada	N***	Y	N
IPMA	Y	Y	N
Met Office	Y	Y	Y
Météo-France	Y	N	N
Met.no	Y	Y	Y
NWS	Y	Y	N
OWM	Y	Y	Y
SMHI	Y	Y	Y
Taps Aff	N	N	N
Trafikverket	N	Y	N
Wunderground	Y	Y	Y
ZAMG	N	Y	N

** Only provides forecasts of warnings *** Only provides textual forecasts

So if you only look at providers that actually provide forecasts and any barometric pressure data at all, that makes 6 of those remaining 10 that provide pressure forecasts. That seems like a large part of the platforms to me.

[MartinHjelmare]

Good! Thanks for the summary.

I'm positive about adding this feature. 👍

We should get some more opinions from other members before moving on.

[fabaff]

I'm OK with adding it as according to the table the popular integrations supports it.

[frenck]

Yeah, looks good! Makes sense.

[helto4real]

I am positive to add it to SMHI pypi lib and fix integration if this is going to happen. And good job making the table of supporting platforms by the way!

[MartinHjelmare]

@bramkragten will this work for the frontend card?

[helto4real]

Now when looking into my pypi lib I realized it is allready implemented so it should be very easy to add it to Home Assistant if barometric pressure is added. I will follow this issue and implement if needed for SMHI.

[bramkragten]

@bramkragten will this work for the frontend card?

Yes, I see no problems there

[MartinHjelmare]

Ok, then I think we can go ahead here and consider this suggestion approved. :+1: