Margarita,

Just to round off the Nor'wester bit, it is definately refering to the wind, real or faked in PW's attic. They are cold because in simplistic terms winds are circular about the weather system creating them. In the Northern hemisphere, a Nor wester is either the lower trailing quadrant of a depression or the leading upper quadrant of an anticyclone; either way if you are on a great circle route between Europe and N America the air mass has been dragged up over the Arctic before it hits you. The only thing to be said in their favour is that they are, generally speaking not as strong as sou'westers, and don't carry as much rain.

Pete M