rolled far to the westward

What is the exact meaning of "rolled far to the westward" in the following passage? It is from the book “Persian Gulf Command” by Ashley Jackson, p288.

Churchill wrote to Brooke on 1 December 1942 that "the role of the Tenth Army is dependent upon the Russian defence of the Caucasus. Since we formed it in August a vast, favourable change has taken place, and it may be that before the end of the year all danger to Persia and Iraq will have rolled far to the westward"

Of course, the meaning is somehow clear: "the danger for Iran and Iraq will be eliminated", but "to the westward" is problematic. Does it mean the danger from west for these two countries will be eliminated? Or does it have another meaning?