Super Typhoon Sinlaku surged into Category 5 status at 11 a.m. EDT on April 12, becoming the world’s second Category 5 tropical cyclone of 2026 as the Joint Typhoon Warning Center rated it with 175 mph winds, or 280 km/h. By Sunday evening, forecasters said the storm had likely reached its peak, with winds near 180 mph, or 285 km/hr, before beginning a slow weakening trend on Monday.
The storm was expected to pose an extremely dangerous threat to the U.S. Northern Mariana Islands on Monday and Tuesday, with the Joint Typhoon Warning Center forecasting that it would pass very near Tinian and Saipan on Tuesday morning. Tinian has a population of about 2,000, while Saipan is home to about 43,000 people.
The weight of the storm showed up in the numbers. At 21Z Sunday, the Japan Meteorological Agency estimated Sinlaku’s central pressure at 905 MB and its winds at 135 mph, or 215 km/h, using a 10-minute average. JTWC later upgraded the cyclone’s peak intensity winds to 185 mph, or 300 km/hr, after a burst of rapid strengthening that added 75 mph in the 24 hours ending at 12Z Sunday.
That surge unfolded over warm Pacific waters southeast of Guam early Sunday, where Sinlaku found a favorable setup of low wind shear, measured at 5-10 knots, sea surface temperatures of 28-29 degrees Celsius, or 82-84°F, and ocean heat content of 125-150 kilojoules per square centimeter. The name Sinlaku was contributed by the Federated States of Micronesia and refers to the goddess of nature and breadfruit of Kosrae Island.
The storm also stands out for how crowded the early-2026 Category 5 field has become. The list of JTWC Category 5 typhoons from January through April included ten storms, a rare pace that puts Sinlaku among a very small group of the season’s most powerful systems. For the Northern Mariana Islands, the immediate concern is not what the storm once was, but how close it will come when Tuesday morning arrives.
