I'm sure there is a simple answer but I am struggling with this one..
You are flying east to west in the Northern Hemisphere at the 500 hPa pressure surface. Which of the following statement is correct?
Then the answers are something like
1) Wind is from the south you are gaining altitude
2) You have a headwind you are gaining altitude
3) You have a tailwind you are gaining altitude
4) If the wind is from the North you are gaining altitude
The answer is if wind is from the North you are gaining altitude... but I can't see you have enough information to get to this or what the question is testing...
any help greatly appreciated