Originally Posted by
ETOPS
Much easier than that...
One line TAF that barely covers half the sheet of paper - we're going!
Ten line TAF - flight cancelled.....
If only that were possible.
A very experienced captain asked me when i was a fresh FO: "Why do you check the weather? we have to fly anyway..". And of course he was right, we have to fly anyway, but it still makes sense to check.
A quick scan of the TAFs gives a pretty good picture how the weather is most likely going to develop, which runways and approaches can be used, if we have to take another alternate or dispatch without an alternate.
According to the book we have to assume whatever has a 40% probability is going to happen, while we can disregard 30%, however, as mentioned above that would depend on the kind of weather, personal experience and willingness to divert.