Sunday morning update: Surigae weakens some while sweeping past Philippines

After making history as the strongest tropical cyclone (typhoon or hurricane) on record during April in the Northern Hemisphere, Typhoon Surigae has weakened some, its peak winds down to 145 mph as of Sunday, equivalent to a Category 4 hurricane. Because its peak winds have dropped below 150 mph, it is no longer classified as a “super” typhoon.

The storm is forecast to weaken further, down to the equivalent of a Category 3 hurricane on Monday, with peak winds of around 125 mph.

The worst of the storm is remaining offshore the Philippines, but its outer bands are bringing heavy rain and gusty winds over the Eastern Visayas and Bicol Region according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).

Saturday afternoon update: Surigae explodes into historically intense cyclone with 190 mph winds

Surigae explosively strengthened to the first super typhoon of 2021 and one of the most intense tropical cyclone in history while edging closer to the Philippines.

The Joint Typhoon Warning Center in Honolulu indicated its peak winds had risen to 190 mph as of Saturday afternoon, equivalent to a high-end Category 5 hurricane. It is the strongest super typhoon ever observed in the northwestern Pacific or anywhere in the Northern Hemisphere during the month of April and so early in the calendar year.

Only four reliably-measured tropical cyclones globally have attained stronger winds any time of the year, according to meteorologist Jeff Masters.

In 36 hours, the storm’s peak wind increased from 90 mph to 190 mph, an astonishing rate of intensification. Scientists have linked an increasing tendency for storm’s to strengthen at such haste to climate change.

The storm is still projected to remain just offshore the Philippines but is predicted by PAGASA to spread moderate to heavy rains, rough surf and gusty winds, especially to the east coast of the central Philippines, on Sunday into Monday. It is expected to gradually weaken to a Category 4 equivalent storm by late Sunday and Category 3 Monday into Tuesday.

Original article from Friday

Typhoon Surigae, previously a tropical storm, is rapidly gaining strength and is set to intensify further over the weekend as it churns through the western Pacific Ocean. Late Saturday into Sunday, it could sideswipe the Philippines and bring gusty winds, heavy rain and rough surf. While it will be a close call, the storm’s worst conditions, equivalent to a Category 4 hurricane, should stay out to sea.

Both PAGASA and the Joint Typhoon Warning Center in Honolulu currently predict the storm to remain just offshore from the Philippines. However, some forecast models suggest that the storm, called “Bising” in the Philippines (which uses a different naming system), could track close enough to the coast to bring hazardous weather.

PAGASA, the Philippines’ meteorological agency, says it may issue a signal 1 or 2 warning (on its 1 to 5 scale for wind impacts), signifying the possibility of modest to moderate wind damage from the typhoon. But it says that if the track of the storm shifts any closer to the coast, “there is a possibility that some localities will be placed under higher levels of wind signal.”

Presently, PAGASA is calling for moderate to heavy rain over the Eastern Visayas and Camotes Islands and the possibility of “flooding (including flashfloods) and rain-induced landslides.”

Surigae is the first typhoon of the season in the western North Pacific, a region known for its annual barrage of fierce storms. Super Typhoon Goni, which struck Catanduanes in the Philippines at Category 5 strength in October, was estimated to be the most powerful storm observed anywhere globally in the previous four years.

Surigae is one of several storms that developed in the past two weeks in the Pacific Ocean, with Cyclones Odette and Seroja swirling through Australian waters earlier in April.

The state of the storm

Surigae was first named on Tuesday and now ranks as the equivalent of a Category 2 hurricane, with maximum winds estimated at 90 mph. It was located about 150 miles north-northeast of Palau, an island nation in the western tropical Pacific, and has already passed well southwest of Guam and the Northern Mariana Islands. The island of Yap in the Federated States of Micronesia encountered gusty winds and squalls, but on Guam proper, impacts were limited to a light breeze and hazardous seas of nine feet or greater on south- and west-facing reefs.

On satellite, Surigae appeared considerably more organized than it had been even eight to 12 hours prior, exhibiting a more symmetrical form amid a circular “central dense overcast” region, or CDO. Convection, or shower and thunderstorm activity, had largely consolidated within this zone, with a few additional spiral rain bands becoming increasingly organized and feeding into the circulation as well.

Several “hot towers,” or locally taller thunderstorm tops, can be seen in one arc of rain squalls northwest of the central dense overcast. Drier air is present southeast of the storm, cutting back a bit on convective activity there.

Farther to the west, the outer periphery of high-altitude outflow clouds and a few showers were affecting central and southern parts of the Philippines.

Satellite imagery also indicated some warming cloud tops toward the middle of the storm, suggestive of sinking air commensurate with the attempted formation of an eye. That’s adjacent to extremely cold, tall cloud tops within a discernible eyewall. While visible satellite imagery indicates the eye has not fully cleared out yet, a local minimum in winds is likely. The eye is likely to improve in structure once vigorous thunderstorms fully wrap around the center.

The forecast

In the coming hours and days, the Joint Typhoon Warning Center anticipates that Surigae will gain more strength. Its environment is ripe for strengthening, characterized by very warm sea surface temperatures between 84 and 87 degrees and relaxed upper-level winds. Wind shear, a change of wind speed and/or direction with height, is weak; that will allow the storm to further blossom unimpeded.

Surigae is expected to make a run at 140 mph Category 4-equivalent strength by Sunday before slowly tempering some as it curves to the northwest and eventually north. The strongest winds will remain in the eyewall, which should pass well out to sea.

Depending on its track, tropical-storm-force winds of 39 mph or greater may or may not scrape the east coast of the Philippines. But even if the storm center stays well offshore, bands of heavy rainfall and breezy squalls would be possible through the weekend, especially in the central Philippines.

There is an outside chance that high pressure over the western Pacific could steer Surigae closer to Luzon than initially forecast; that’s something that will have to be monitored.

Thereafter, Surigae should drift out to sea and eventually weaken, potentially affecting the jet stream and influencing the upper-air weather pattern over the Pacific and even North America into May. Confidence on how that may evolve is very low.

The Pacific cyclone season to date

Before Surigae became the first Pacific typhoon of the season, a tropical storm named Dujuan brought flood rain and wind gusts approaching 45 mph to the central Philippines in late February. In addition, tropical depressions formed in January and March.

South of the equator, where cyclone season is drawing to a close, it has been an active one. Storms there aren’t typically as strong as in the North Pacific or Atlantic, and as a result Australia and Fiji use a different scale. One storm — Niran — attained Category 5 strength, although it would match only a level 3 on the Saffir-Simpson scale.

On April 8, Odette and Seroja orbited one another in a Fujiwhara dance northwest of Australia. Odette petered out, while Seroja affected northern regions of Western Australia with winds gusting up to 110 mph.

In the Atlantic, meanwhile, meteorologists are gearing up for what could be another busy hurricane season.

correction

A previous version of this article incorrectly referred to Cyclone Seroja as Sergia. The error has been corrected.