Dispatch will absolutely spit out a plan going through bad weather. Will it make it to our FMS? Depends...
Either we catch it on the ground....or ATC will have a reroute planned (usually going to a major airport where an arrival is f'ed.)
Unfortunately I am usually dismayed at the amount of fuel we're given...I know dispatch is under the gun to get a full load of people on the plane, so I think they just throw the plan together seeing if we call them on it. Sorry but I don't like have just the canned plan when there are TS in the terminal area that could affect landing.
I always say....It makes no sense that we need an alternate for the 1,2,3 rule (I've never not made it into an airport with 1800' ceilings) yet a TAF that calls for Tempo TSRA and a 3000' ceiling is cool....no alternate needed. Or the VCTS that can turn into storms on the field in the drop of a hat.
I've had a situation where we left with a canned plan and VCTS and the field ends up with storms as well as the next closest logical alternate having TS...Having to truck around summer wx and looking at landing with less than 45 minutes is not cool. (We landed with 1500ish = 35 min).
Also unless something really catches dispatches attention, usually you're the one who has to start the dialog.
