Super Typhoon Jelawat
© NASA/NOAA Suomi NPP/VIIRSSuper Typhoon Jelawat on March 30, 2018.
Typhoon Jelawat not only became the first typhoon of 2018, but then exploded into a Category 4 super typhoon, a relative rarity this early in the calendar.

Jelawat was first categorized as a tropical depression last Saturday, then strengthened to become the year's first typhoon Thursday afternoon, U.S. time.

Over the western Pacific Ocean north of the equator and west of the International Dateline, tropical cyclones are called typhoons when they strengthen to the equivalent of a hurricane.

But Jelawat, named for a Malaysian word for a freshwater fish, wasn't content to merely slide across the typhoon threshold.

Because of a west-to-east cocoon of lower wind shear, strong outflow winds aloft providing ventilation for thunderstorms, and some warmer than average ocean water, Jelawat rapidly intensified, gaining 70 knots (roughly 80 mph) of intensity in just 24 hours, becoming the equivalent of a Category 4 super typhoon by Friday morning, U.S. time.

Jelawat will track in a general east-northeast direction, first steered by high pressure to its southeast, then eventually picked up by the jet stream and whisked away well north of Guam, posing no threat to the Philippines, Taiwan, China or Japan.

The typhoon should weaken fairly quickly over the next several days.

Notably Early For This Intense a Typhoon

While intense typhoons are the norm every year in the western Pacific basin, they're much less frequent in the first three months of the year.

Jelawat became only the fourth super typhoon to occur from January through March in reliable records dating to 1971.


An average of 25 tropical cyclones form in the western North Pacific basin each year, accounting for almost one-third of the planet's tropical cyclones, by far the most of any basin.

This is the only basin on Earth to consistently see tropical cyclones form any month of the year. However, the majority of them form May through December, according to a 2017 study.

In 2017, there were 27 named storms in the western North Pacific basin. Twelve of those strengthened to typhoons.

Interestingly, 2017's first typhoon wasn't until summer, when Super Typhoon Noru rapidly intensified into the equivalent of a Category 5 hurricane, the year's strongest in the basin.

In 2015, a pair of typhoons, Mekkhala and Higos, formed in January and February, respectively. From late March through late May, three Category 5 super typhoons - Maysak, Noul and Dolphin - erupted over the basin.