UPPER WIND RULE
With you back to the wind the cold air is to your left in the northerrn hemisphere.
(This law stems from Sent Clowns comment and he explains why we talk about temperature when it comes to upper winds)
So, draw an plan view aircraft heading up the page i.e. 360°, stick a wind from the left going across the aircraft to the right.
Now, turn the page so that the wind you have drawn is passing through your back and out your chest and point outwards infront of you. On the your left hand side is where the cold air is, which by the way, if you look at your aircraft, is exaclty where it is headed.
Therefore the cold air is infront.
JAA likes these questions and they are very simple when the penny drops. If you can't get to grips with this, dont write the paper, see your instruvtor and sort it until you can do these blind folded. This concept is tested in many ways, especially altimetry.
The same applies to jet streams, since they are just quick uppper winds
Good luck
Steve Francis
If all else fails, buy the Met CD I made, and if Pprune is worried I'm advertising, I'm unemployed right now and I don't get a penny from it's sales, students praise it enough anyway.
Fullrich, you have some very muddled ideas here, if you need it sorting gimme a holler