Roll Cloud
In the Southern Hemisphere the weather fronts would normaly come from the South West and proceed to the North East.
On cloud seeding operations we spent a lot of time working ( or playing ) with these fronts.
I can remember one one occasion a roll cloud formed on the leading edge of the air mass. The Cessna 310 sat nicely right on the top of the roll cloud, in the clear, very little turbulence and throttles reduced. A spectacular flight in all ways and it lasted for many miles. The escape plan was to turn left into the clear.
Tmb