At a Glance

A typhoon hasn't formed in the Western Pacific Basin since February.Tropical cyclone activity in the basin has been roughly half of normal through late July.Only two other years since the 1970s had such a lack of typhoons.This lull won't last. The most active time of year is ahead.

The Western Pacific Basin has been eerily quiet so far in 2019, with roughly half the tropical cyclone activity of an average year through July.

On Feb. 25, Super Typhoon Wutip became the typhoon on record, with estimated winds up to 160 mph west of Guam.

Since then, it has been quiet.

It's been five months since the last typhoon. That's only the third time since 1950 the basin has failed to generate a single typhoon from late February through late July, according to Dr. Phil Klotzbach, a tropical scientist at Colorado State University.

There have been five other tropical storms this year, including a weird January landfall in Thailand from , but none of them have been intense or long-lasting.

The six named storms through late July are two fewer than the of eight named storms, according to Digital Typhoon.

But using a metric called the ACE index, which sums up both duration and intensity of all named storms, the activity in the Western Pacific Basin through July 30 was barely half of the average year-to-date, according to Klotzbach.

Year-to-date ACE index values (in purple) compared to average-to-date (in green) in each Northern Hemisphere tropical cyclone basin.

(Data: Dr. Phil Klotzbach/Colorado State University; Graph: Infogram)

The current weak El Niño may have had a suppressive effect in parts of the Western Pacific Basin.

A in the Journal of Climate found that stronger El Niños tend to shift tropical development away from Asia farther east in the western Pacific Ocean.

This periodic warming of waters near the equator in the central and eastern Pacific Ocean produces a circulation in the atmosphere.

The Western Pacific Ocean is typically in a downward branch of this so-called Walker Circulation. Downward motion in the atmosphere suppresses clouds and rain, and would therefore limit the number and intensity of tropical cyclones in at least part of the basin.

A typical Walker Circulation during an El Niño, with the branch of sinking air near the Western Pacific Ocean highlighted in red.

(NOAA/Climate.gov)

This Likely Won't Last

The Western Pacific Basin is for tropical cyclones due to a vast expanse of warm water, a lack of dry air that invades the Atlantic Basin and a year-round "season."

From 1981-2010, an average of 26 Western Pacific named storms formed each year, 17 of which become typhoons, more than double the average of Atlantic Basin named storms (12) and hurricanes (6).

Since these Western Pacific systems can form any time of year, there really is no season, per se.

Like the Atlantic Basin, the Western Pacific Basin has a peak in activity in summer and fall, but it's much longer-lasting, typically from July through November.

It's remarkable a super typhoon formed in February, the least active time of year, as shown by the climatology graph below.

Average yearly Western Pacific tropical cyclone activity, color-coded by intensity, from 1959-2010. Western Pacific tropical cyclones can form any time of year, but are most numerous from July through November.

(Paul Stanko (NWS-Guam) via NOAA/AOML/HRD)

So don't count on a quiet start portending a relatively benign year.

Furthermore, NOAA expects El Niño to , which may remove any suppressing effect it may have had on the Western Pacific Basin.

Consider what happened just three years ago.

A transitioned to its opposite, La Niña, by late summer.

The first storm of 2016 didn't form until early July, a without a single Western Pacific tropical storm or typhoon.

Despite the late start, 26 named storms, 17 of which reached typhoon intensity, formed in 2016. This included several super typhoons, including , , , and .