Ever year around June, the high-altitude air current known as the jet stream lunges into the Himalayas, whose towering 8,000-meter peaks slice it into two branches that soar eastward over Asia toward the Pacific. Near Japan, they finally reunite and embrace between them a colossal mass of cold oceanic air lying off Hokkaido.

Meanwhile, as the whole of Asia begins to cook in the summer sun, a hot air mass develops over the continent, setting off a vast northeastward migration of air along the East Asian coastline. The flow encounters a burgeoning accumulation of damp air centered off Micronesia, helping to draw it toward the continent.

There is conflict in the heavens: The warm air wants to spread out, but the cold air puts up resistance. The two titans clash.