Typhoon Noru, the Western Pacific's First of 2017, Begins Weird Fujiwhara Effect With Tropical Storm Kulap

At a Glance

• After a relatively dull start to the year, the western Pacific Basin now features multiple tropical cyclones.
• Typhoon Noru is now pulling nearby Tropical Storm Kulap into a daisy-wheel dance called the Fujiwhara effect.
• Once Kulap is ingested, Noru may spin in the western Pacific for another 1 to 2 weeks.
• Only once in the past 67 years has the first typhoon formed later in the year.

Typhoon Noru, the first typhoon of 2017, is now teaming up with another tropical cyclone named Kulap to its northeast, kicking off a rare, bizarre, circular dance called the Fujiwhara effect. 

(MORE: Hurricane Central)

Currently, Typhoon Noru and Tropical Storm Kulap are both spinning well to the east of Japan. The westernmost one is Noru, with Kulap about 600 miles to the northeast of Noru.

Also roaming the western Pacific basin is Tropical Storm Sonca which will move ashore in Vietnam Tuesday. If that wasn't enough, another disturbed area, Invest 99W, could become the next west Pacific named storm sometime in the week ahead.

Noru is more impressive looking than Kulap in satellite imagery right now, though, admittedly, Noru's presentation isn't all that impressive for a typhoon.

Despite their lack of intensity, their interaction this week is meteorologically fascinating.

Noru is currently moving toward the east-southeast, while Kulap moves west-northwest. In essence, each is now revolving about a point between them, a daisy-wheel meteorologists call the Fujiwhara effect. 

Named for a Japanese researcher who discovered this in experiments with water in the early 1920s, the Fujiwhara effect details how two tropical cyclones 800 to 900 miles apart rotate counter-clockwise about one another. Think of the teacup ride at Disney or the Tilt-a-Whirl at your local county fair, but with tropical systems instead.

Once Kulap is to the northwest of Noru, Noru is expected to turn north briefly, then turn back toward the west again in a switchback or hairpin turn, crossing its previous path from late last week.

(FORECAST PATHS: Noru | Kulap)

"The western tropical cyclone (Noru) is going to be the center of gravity, in a sense, where the smaller system (Kulap) is forecast to cyclonically orbit the larger system for a couple of days," said Dr. Michael Ventrice, meteorological scientist with The Weather Company.

Typically, the stronger storm will dominate the weaker, either fizzling it or merging with it altogether.

Ventrice said he believes Noru's outflow will suppress convection for the smaller Kulap once they begin to interact. Forecast guidance suggests Noru may essentially ingest Kulap later in the week. 

After that happens, Noru may drift farther west and loaf around south and southeast of Japan well into next week. It certainly makes for strange-looking model forecast tracks.

Why is this happening? Blame a clogged-up upper atmosphere.

Given this blocked atmosphere, we can't completely rule out Noru eventually creeping closer to Japan sometime near the end of July or early August.

Regardless, this long-lasting tropical cyclone will churn up impressive swells that may reach not just Japan's east coast, but may also propagate farther south and west.

Not to mention, the satellite imagery from this potential Fujiwhara effect may be among the most impressive weather imagery of 2017 to meteorologists and weather enthusiasts alike.

But wait, there's more! According to the National Hurricane Center, a second Fujiwhara effect for the Pacific Ocean is possible later this week in the eastern Pacific between Hilary and Irwin. These two tropical cyclones could undergo this weather waltz well off the coast of Mexico. 

Having two Fujiwhara interactions in one ocean within a week is rare. 

Near-Record-Late 'First Typhoon'

If you haven't heard the word "typhoon" in a while, it's because Noru is the first of 2017.

Through July 19, there were only four tropical storms – Muifa in late April, Merbok in mid-June, Nanmadol in early July, Talas in mid-July – in 2017 in the northwestern Pacific Basin.

According to Dr. Phil Klotzbach, Colorado State University atmospheric scientist, three to four typhoons have typically developed by mid-July in an average year. Two of those typhoons would have reached at least Category 3 intensity in a typical year-to-date, as well.

Since 1950, only 1998 (Aug. 3) had a later "first typhoon of the year," Klotzbach noted.

"One of the reasons for suppression of the (Northwest Pacific tropical cyclone) season to date is that we've generally had sinking motion across most of the basin since early May," said Klotzbach.

Stronger-than-average trade winds, blowing east-to-west near the Philippines, Taiwan and the South China Sea, have also been in place since May, Klotzbach said. This increases wind shear, which tends to either prevent tropical cyclones from forming or rip apart those that have formed.

(MORE: Which Countries Get Hit Most by Tropical Cyclones?)

Klotzbach's calculations indicate roughly 80 percent of the year's activity, on average, still lies ahead in the planet's most active basin for tropical cyclones: the northwest Pacific Ocean.

Jonathan Erdman is a senior meteorologist at weather.com and has been an incurable weather geek since a tornado narrowly missed his childhood home in Wisconsin at age 7. Follow him on Facebook and Twitter.

MORE ON WEATHER.COM: Atlantic Basin Retired Hurricanes and Tropical Storm Names