[eyelidlessness]

Rolling your own weather forecast is more akin to rolling your own election forecast (ahem).

Equally dangerous, but not designed to be private and a huge different set of risks.

[ehvatum]

Political motive to change weather forecasts, and weather motive to change political forecasts.

Very dangerous.

[transportguy]

depends what you mean by 'rolling your own weather forecast'. If by that you mean you're going to do some statistical modelling on ensemble data, you're going to get a much better idea of what is likely to happen than you can from the average datasets you get on sites like windy