Fraternal twins were born in the western Pacific Ocean this weekend. Two typhoons—Goni and Atsani—developed at the same time within a few hundred miles of each other, but each storm took on a life of its own and will have dramatically different outcomes. Typhoon Goni poses the greatest threat to land, coming dangerously close to countries like Taiwan and Japan.

(Note: the top image is a 5.91 MB gif, so it may take a second to load. It’s worth the short wait.)

Super Typhoon Atsani is the largest (and easternmost) of the two, thriving in the warm waters and favorable environment 1,600 miles to the east of Typhoon Goni and 1,250 miles south-southeast of Tokyo. Most observers watched the storms with deep interest to see if they would both peak as super typhoons at the same time (a designation roughly equivalent to a category five), but Atsani got there first.

The latest advisory from the Joint Typhoon Warning Center (whose website works about 12% of the time) shows Atsani roaring with winds of around 160 MPH, and after a brief bit of weakening tomorrow, regaining its former intensity through Friday before it begins a slow weakening trend. The storm is on a track that takes it closer to the main islands of Japan before it runs into a ridge of high pressure, causing it to abruptly shift direction and race out to sea toward Alaska.

Goni (shown above), while a little less intense than Atsani, is a much more serious threat to the countries of eastern Asia. Just looking at that ridiculous eye on satellite imagery shows that the storm means business. The latest forecasts from both the JTWC and Japan Meteorological Agency show Goni/Ineng* coming dangerously close to the northern Philippine island of Luzon before making a hard right turn toward the north, grazing Taiwan while raking the isolated Ryukyu Islands of Japan.

*PAGASA, the weather bureau of the Philippines, names typhoons near the country independent of the World Meteorological Organization’s official list of names. This particular typhoon has two names because of this quirk in convention: Goni, the official WMO name, and Ineng, its name assigned by the Philippines.

Goni’s eye will likely come very close to the northeast corner of Luzon before shifting northeast—this won’t save the island’s residents from the effects of high winds and heavy rain, however, and the situation will grow more dire the closer the eye comes to shore.

Due to its location, Typhoon Goni’s northeastward turn won’t take it harmlessly away from land like we’re going to see with Atsani as it scoots away from Japan. The latest run of the GFS model, for example, shows Goni affecting the Ryukyu Islands before making landfall as a very intense storm on Kyushu Island, which is the southernmost island on the main Japanese archipelago, home to the city of Fukuoka and more than 13,000,000 people.

The above forecast from the Japan Meteorological Agency shows Goni’s predicted path, along with the gigantic cone of uncertainty, illustrated by the growing circles at each point in time in the forecast. The cone of uncertainty is the historical track error in the forecast—for instance, at day four in the forecast period, the actual location of the center winds up within the diameter of the largest circle 70% of the time. That’s anywhere from Taiwan to mainland China to Japan or out to sea.

The center of the storm will likely stay close to the center of the circle—give or take a few dozen miles—but a few dozen miles with a storm like this means the difference between a cloudy day and destructive winds and rain.

If you’re currently in eastern Asia or have plans to visit over the next week or so, keep a very close eye on Goni’s track and be prepared to take action if you have to evacuate or change your travel plans. Okinawa in particular could be in for a rough day or two if this current forecast holds true.

[Images: JMA, JTWC, Google Earth, JMA]

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