Typhoons in the northwest Pacific are no different from hurricanes in the Atlantic; they are just called different things. To become a “super typhoon,” a storm must attain sustained winds of at least 150 mph.
As Hinnamnor barrels westward, the main body of Japan isn’t under any watches or warnings yet, but storm and high-wave warnings have been hoisted for the Daito Islands southeast of Okinawa, which are home to about 2,100 residents. The two small populated islands, Minamidaitojima and Kitadaitojimasit about 200 feet above sea level at their highest point and are made out of limestone that built up atop ancient coral reefs.
The storm center is predicted to pass 93 miles south of Kadena Air Base on Okinawa at 7 pm local time Wednesday, producing up to 5 to 6 inches of rain and wind gusts up to 69 mph, according to Stars and Stripes.
It’s unclear just how close the storm will get to the more densely inhabited islands of Japan, as well as how the storm could eventually influence the weather in North America.
On Tuesday, the Japanese satellite Himawari-8 captured eerie views from above as the atmospheric buzz saw crawled west. The storm was a rather compact “annular cyclone,” characterized by one intense band of convection, or thunderstorm activity, surrounding a hollowed-out eye. Most hurricanes, typhoons and mature tropical cyclones feature a spiral of arcing squall lines and rain bands feeding into the center. Annular cyclones have a tighter radius of maximum winds and are more symmetrical, which helps them sustain their ferocity.
On the periphery of the typhoon, high, thin, wispy cirrus clouds can be seen on satellite radiating away from the center. That marks outflow, or exhaust at high altitudes as “spent” air expands away from the storm. The more already-processed air a storm evacuates from above it, the more the internal air pressure can plummet. That means the storm can in turn ingest more moisture-rich surface air in contact with the ocean. That fuels its sustenance or intensification.
Hinnamnor will probably maintain its strength for another day or so before the possibility of some modest weakening.
Regardless, it’s already the strongest storm to spin up on Earth this year, and it could be very problematic wherever it strikes. In fact, it’s still expected to be at least a Category 3 storm five days from now.
It appears Hinnamnor may curve slightly southward, suppressed by high pressure to the north. This will probably keep its center just south of the island of Okinawa, but either way it’s much too close for comfort. The Japanese islands of Miyakojima, Tarama and Ishigaki appear to be at greater risk, with the closest pass probably sometime Friday or Saturday.
By then it will probably be faltering just a bit, and it may weaken to a Category 3 or low-end Category 4 storm, but severe impact is still expected. Weather models diverge markedly in their simulations thereafter but agree on the same basic premise: An approaching low-pressure system to the northwest will help scoot Hinnamnor northward.
The American (GFS) model then suggests Hinnamnor will slam early next week into South Korea, which endured disastrous flooding just three weeks ago. The European model favors a somewhat weaker Hinnamnor crossing over southern Japan with hurricane-force winds and copious rainfall.
It unfortunately appears that either scenario will continue to starve China of meaningful rainfall. The country has been facing a blistering heat wave and brutal drought that’s wreaking havoc on agricultural production.
There’s a remote possibility that Hinnamnor’s eventual absorption into a mid-latitude low-pressure system in seven to 10 days could bend the jet stream enough to even influence the weather in North America in the next two or three weeks. Picture throwing a rock into a gently flowing stream. That rock would affect the flow around it, resulting in ripples downstream. The crests and troughs of those ripples are analogous to high- and low-pressure systems. The specifics of how such a chain reaction may play out remain to be seen.
Hinnamnor’s fit of fury comes amid an anomalously quiet season for tropical cyclones in the northern hemisphere. Thus far the hemisphere’s tropical storm activity is only running about 53 percent of average, with half the number of expected major hurricane-strength systems.
In the meantime, meteorologists are also carefully monitoring a system in the Atlantic that will probably become Danielle and could make a run at hurricane strength next week. All indications point to it heading out to sea and sparing the US, although it could be something to monitor for Bermuda.