If there was a way to know - behind the scenes - in the game code for example -when the weather was going to change, and whether or not it would worsen or improve a mod could be very easily implemented.
within 48 hours of the weather change the report text would indicate current weather, wind direction and speed and indicate one of the following parameters
a. Barometric Pressure steady (displayed when the weather will not be changing within 24 hours.)
b. Barometric Pressure increasing (displayed when the weather will be improving within the next 24 hours)
c. Barometric Pressure increasing rapidly (displayed when improving weather is imminent - say within 10 hours)
d. Barometric Pressure decreasing (displayed when the weather will be worsening within the next 24 hours)
e. Barometric Pressure decreasing rapidly (displayed when poor weather is imminent - within 10 hours or so)
This would allow the player to make strategic decisions based on weather data that would be available to a U-boat or any ship for that matter.
If the weather report indicated "Skies clear, winds 240 degrees at 10 m/s, barometric pressure falling rapidly" and the player was a mere 5-6 hours away from intercepting a convoy he could then alter his tactics or stalk the convoy and wait for the weather to improve
it is unfortunate that the weather in SH3 is "global" instead of "local"... in other simulation games where weather is a factor - like Flight Simulator X for example... you can fly from an area of relatively good weather into an area of thunderstorms and can see the thunderstorms as they approach from 60-100 miles away
Silent hunter III's lack of this type of weather also removes strategic elements from the game like escaping into a storm. if you have escorts in pursuit of you, IRL you might be able to escape into a fog bank or an isolated rain shower where visibility is decreased considerably. furthermore, the radar systems in SH3 on enemy DDs do not appear to be impacted by weather as they should.
in closing... i think a mod could easily be added to the game as long as the weather routine could be figured out, whatever event triggers that change, as long as the weather change is not almost immediate, you could tie the "barometric pressure rising" text to a known time frame or known percent change of an improvement in the weather
__________________
|