I'll add to this (as a private pilot) - there are also a lot of requirements of weather at your destination; in terms of wind, visibility, temperatures and how

I'll add to this (as a private pilot) - there are also a lot of requirements of weather at your destination; in terms of wind, visibility, temperatures and how long those forecasts are valid for and so forth. In order to dispatch a flight you need to ensure that the weather at the arrival airport meets certain minima at that point in the future (hence the need for forecasts), and so does that at suitable alternative airports, and enough fuel is carried to be able to divert (depending on a heap of other factors such as aircraft load, capacity, prevailing winds enroute, at destination, time of day and so forth). Aircraft are then also required to check the AWIS/ATIS or the Tower (usually the most reliable source of weather at an airfield) to ensure that the weather at the destination is within their safe margins. There's the FAA requirements, and then airlines and aircraft and airports then also have their own established minimum requirements that all need to be within the safe range. You can certainly dispatch a flight with potential updates and diversions as they progress / get closer to the destination, but with an outage and no means to update the enroute aircraft - there's usually no easy safe or legal way to dispatch them.