Super Typhoon Surigae exploded into a high-end category 5 typhoon with 180 mph winds and a central pressure of 905 mb at 8 a.m. EDT (8 p.m. Philippines time) Saturday, April 17, 2021, in the waters about 200 miles east of the Philippines.

UPDATE: At 2 p.m. EDT Saturday, April 17, the Japan Meteorological Agency put Surigae’s central pressure at an astounding 895 mb, beating the previous record low pressure for a typhoon this early in the year by 15 mb. (Previous record: 910 mb, Super Typhoon Maysak, Mar. 31-Apr. 1, 2015.) The Joint Typhoon Warning Center put Surigae’s peak 1-minute average winds at 190 mph, making it the strongest typhoon so early in the year, as rated by the Joint Typhoon Warning Center, JTWC. (Previous record: Super Typhoon Hester, 185 mph winds, January 1, 1953.)

Astonishingly, only four tropical cyclones worldwide have been *reliably measured* with higher 1-minute average wind speeds:

Northeast Pacific:
Hurricane Patricia (2016), 215 mph winds, 872 mb pressure. Made landfall in Mexico with 150 mph winds.

Northwest Pacific:
Super Typhoon Goni (2020), 195 mph winds, 894 mb pressure. Made landfall in the Philippines with 195 mph winds.
Super Typhoon Haiyan (2013), 195 mph winds, 895 mb pressure. Made landfall in the Philippines with 190 mph winds.
Super Typhoon Meranti (2016), 195 mph winds, 890 mb pressure. Made landfall in the Philippines with 190 mph winds, then in China with 100 mph winds, killing 47 people.

Further intensification questionable

Satellite imagery suggested that Surigae (the Korean word for a type of eagle) had continued to intensify for a few hours after the 8 a.m. EDT advisory, but then began to weaken by early afternoon. The typhoon had favorable conditions for intensification, with warm waters near 30 degrees Celsius (86°F), light wind shear of 5-10 knots, and a moist atmosphere. However, microwave satellite imagery on Saturday morning showed that Surigae was developing concentric eyewalls, which likely presages the onset of an eyewall replacement cycle. This process, common in intense tropical cyclones, results in a temporary weakening by 10-20 mph, as the inner eyewall collapses and is replaced by a larger-diameter outer eyewall. If this process is underway, Surigae may already have peaked in intensity. By Sunday, Surigae will encounter less favorable upper-level winds, which will likely result in a slow weakening trend.

Figure 1. Microwave satellite image (89 GHz) of Super Typhoon Surigae at 2 a.m. EDT April 17, 2021. At the time, JTWC rated Surigae a category 5 storm with 160 mph winds. Concentric eyewalls are apparent on the image, likely presaging the onset of an eyewall replacement cycle. (Image credit: Navy Research Lab, Monterey)

Surigae’s core expected to stay offshore from Philippines

At 8 a.m. EDT Saturday, Surigae was headed northwest at 14 mph, on a track roughly parallel to the Philippines. The storm’s outer spiral bands were bringing heavy rain to the eastern Philippines, but the core of the typhoon is expected to remain offshore, and the islands will only be affected by the weaker left-hand side of Surigae’s circulation. Surigae is predicted to turn to the north by Monday, and then recurve to the northeast over open water later in the week, avoiding landfall.

A historic storm for so early in the year

The list of category 5 typhoons classified by JTWC for the months of January-April is a short one, with just nine storms:

Hester, 185 mph winds, Jan. 1, 1953;
Surigae, 180 mph winds, Apr. 17, 2021;
Maysak, 175 mph winds, Mar. 31, 2015;
Thelma, 175 mph winds, Apr. 20, 1956;
Wutip, 165 mph winds, Feb. 23, 2019;
Isa, 165 mph winds, Apr. 20, 1997;
Mitag, 160 mph winds, Mar. 5, 2002;
Andy, 160 mph winds, Apr. 21, 1989; and
Ophelia, 160 mph winds, Jan. 13, 1958.

Surigae is Earth’s third category 5 storm of 2021, joining two Southern Hemisphere cyclones that peaked with 160 mph winds:

Tropical Cyclone Faraji in the southwest Indian Ocean (February 8); and
Tropical Cyclone Niran in the South Pacific Ocean (March 5).

There are only two other years on record when Earth has recorded as many as three category 5 storms by April: 2015 and 2003, when each had three Cat 5s in the Southern Hemisphere.

Figure 2. Eight category 5 super typhoons in the northwestern Pacific during the months of January-April, as classified by JTWC in NOAA’s database (Andy of 1989 was inadvertently omitted from this plot). (Image credit: NOAA)

A busy typhoon season coming?

Surigae is the northwestern Pacific’s second named storm of 2021. The first was Tropical Storm Dujuan, which peaked with 50 mph winds on February 19 to the east of the Philippines. The season’s second named storm usually doesn’t form until the second week of May, so 2021 is off to an early start in multiple ways. However, it’s not that unusual to see a category 4 or 5 super typhoon by April 17. This has occurred seven other times since 2000 – most recently on February 23, 2019, when category 5 Super Typhoon Wutip peaked with winds of 165 mph.

The large-scale environment for typhoon formation in the northwest Pacific is more favorable than it was last year. More warm water is present, and La Niña is now fading toward neutral conditions. Indeed, the counterclockwise circulation of air around Surigae will help push warm water eastward in the tropics, helping move conditions even farther away from La Niña. La Niña conditions tend to shift the breeding grounds for typhoon formation closer to the coast of eastern Asia, reducing the time a storm will have over water, and thus limiting intensification potential. Sea surface temperatures are about 1 degree Celsius (1.8°F) above average across a large region of ocean to the east of the Philippines – a prime breeding ground for intense typhoons – so this year may feature more intense typhoons than average.

Early indications are that the 2021 typhoon season will be at least average in activity, and possibly above average. The private forecasting firm TSR is to issue its first seasonal forecast for typhoon season in early May.

Thanks go to Jasper Deng and Bob Henson for assisting with this post.

Also see: Climate change is causing more rapid intensification of Atlantic hurricanes

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Jeff Masters, Ph.D.

Jeff worked as a hurricane scientist with the NOAA Hurricane Hunters from 1986-1990. After a near-fatal flight into category 5 Hurricane Hugo, he left the Hurricane Hunters to pursue a safer passion -...