Take a look at "hot, hot, hot." the article states:
in this case, the dome of high pressure also pushed the jet stream and its drier, cooler air, farther north than normal, into canada. meanwhile, hot, humid air from the gulf of mexico circulated clockwise around the dome, traveling farther inland than normal.

in the word circulated, the suffix –ate must mean?

a. to multiply
b. to oppose
c. to cease
d. to make