Answer:
First of all, think of nature as a thing that cannot be predicted, things are happening all the time, for example, at the tectonic plates , and we have no idea when an earthquake will happen again. The thing is, humans will probably never forecast weather with 100% accuracy, it's more likely that we can predict things that are going to happen moments after, and this is already possible, but forecasting is a bit more complicated than that.
The challenges we face on trying to forecast weather is that a lot of technology and good scientists is needed for that, and some countries don't have that, or if they do, they prefer to protect themselves against natural disasters than trying to forecast them.
And not all of the countries have the financial capability to support the development of technology, and yes, countries should help each other on this process, because above all things, we are humans, and protecting this race needs to happen, and for that, these countries that have more resources must help those who don't have that as an ethical obligation.