No Northern Hemisphere Tropical Cyclones Near Atlantic Season's Peak A First In 38 Years

Jon Erdman
Published: September 12,2015

A funny thing happened as we reached the peak of the Atlantic hurricane season. Not only did the fledgling Atlantic storms (Grace and Henri) die off, but the hyperactive Pacific also went quiet.
Infrared satellite imagery from September 12 showed a few fledgling clusters of convection along the Intertropical Convergence Zone, but no active tropical cyclones, or even a single disturbance meriting extra attention.

Infrared satellite image of the northwest Pacific, northeast Pacific and Atlantic basins on September 12, 2015.

Despite being in the season's peak, it is not unusual at all to have one or multiple September days without a named storm active in the Atlantic basin. That happens most every year.
What's impressive is how the entire Northern Hemisphere has taken a breather at the same time, in mid-September.
Colorado State University tropical meteorologist, Dr. Phil Klotzbach (Wunderblog) said it was the first time a September 12 lacked a single tropical storm, hurricane or typhoon in the Northern Hemisphere since 1977.
Klotzbach also said it was the first time since July 29 the hemisphere had taken a tropical cyclone break. In that time, there had been 18 tropical cyclones combined in the Atlantic and Pacific basins.
Hurricane specialist Michael Lowry said in an internal tropical update it was the first time since two days before the summer solstice -- June 19 -- there were no areas to watch, invests, or named storms in the western, central or eastern Pacific.
Since that time, there have been a whopping 24 named storms of at least tropical storm strength in the Pacific, including 10 typhoons or hurricanes reaching at least Category 4 intensity.
Lowry also noted that, for the first time in awhile, Hawaii wasn't threatened by a tropical storm this week.

(MORE: Hawaii's Hurricane Fatigue)
Persistent, stubborn wind shear -- boosted by a strong El Nino -- and dry air have thwarted tropical cyclones from intensifying or lasting very long in the Atlantic this season.
In the western Pacific basin, the atmosphere has become markedly more stable than average for this time of year, according to an analysis from CIRA/RAMMB. A more stable atmosphere suppresses the development of persistent convection needed to develop tropical cyclones.
(RECAPS: Japan's Destructive Flooding | Before/After Imagery)
Meanwhile, sea-surface temperatures remain well above average in the central and eastern Pacific basins, but wind shear has picked up a bit in recent days, according to an analysis from UW-CIMSS.

Season-to-date named storms through September 11, 2015 (left column) and full-season average named storms (right column) in the four major tropical cyclone basins of the Northern Hemisphere.

This lull isn't likely to last long, particularly in the Pacific.
An average eastern Pacific hurricane season sees five more named storms, three of which become hurricanes from mid-September on.
Stronger El Ninos typically lead to late-season named storms in the central Pacific, which may, yet again, threaten the Hawaiian Islands.
While the Atlantic may struggle to maintain long-lived tropical cyclones from the deep tropics during this strong El Nino, more home-grown systems spinning up much closer to the U.S., such as we had with Ana and Bill early in the season, could still occur into October.

MORE: Etau's Devastating Japan Flooding (PHOTOS)