Typhoon Wutip, known in the Philippines as Tropical Depression Betty, was the most powerful February typhoon on record, surpassing Typhoon Higos of 2015. The third tropical cyclone, second tropical storm, and the first typhoon of the 2019 Pacific typhoon season, Wutip originated as a tropical disturbance near the Marshall Islands on February 12, that generally tracked westward, passing just south of the Federated States of Micronesia (FSM), before organizing into a tropical depression on February 18.
The depression was later classified a tropical storm a day later, attaining the name Wutip from the Japan Meteorological Agency. The storm gradually intensified as it turned northwest, before it underwent rapid intensification on February 23, while passing to the southwest of Guam, and reached its first peak intensity. With winds of 270 km/h (165 mph) estimated by the Joint Typhoon Warning Center, Wutip became the first Category 5-equivalent super typhoon on record in the month of February. Wutip underwent an eyewall replacement cycle shortly afterward and weakened. The storm finished its cycle on February 24, rapidly intensifying once again. Wutip reached a secondary peak intensity the following day, again attaining Category 5-equivalent winds. Thereafter, Wutip rapidly weakened for the rest of its lifespan from strong vertical wind shear, before dissipating over the Philippine Sea on March 2.
Before becoming a tropical depression, Wutip poured heavy rain across the Marshall Islands. As tropical cyclone watches and warnings were issued and citizens sought shelter, Typhoon Wutip crossed the FSM and inflicted significant damage towards its agriculture and infrastructure, contaminating water sources across the affected islands with its floods and leaving 11,575 people in need of food. Later on, Wutip induced power outages in Guam and caused damage that added to the total of over $3.3 million (2019 USD). The Northern Mariana Islands received minor impact, and there were no casualties reported in any of the affected areas nonetheless. In response to the effects, both the FSM and Guam received aid from international governments and organizations.
Meteorological history
Typhoon Wutip originated as a large mass of cumulonimbus clouds near the Marshall Islands on February 12, 2019, forming at a low latitude of 3°N. Initially disorganized, the slow-moving cluster consolidated into a more cohesive system, expanding north. On February 16, the Japan Meteorological Agency (JMA) detected the system as a low-pressure area moving westward. While southeast of Kosrae, vigorous convergence of trade winds north of the tropical disturbance spawned sporadic convection, or thunderstorms. A circulation was later detected the next day by a scatterometer, seemingly aided by the storm's twin cyclone in the Southern Hemisphere, Cyclone Oma. However, southeasterly vertical wind shear separated convection from the circulation for two days, possibly influenced by Oma's outflow. After further organizing, the JMA marked the system a tropical depression on February 18. The convection then broadened over the system's large but weak circulation, as it situated over an area of low wind shear and warm sea surface temperatures of —conditions which are conducive for tropical cyclogenesis; the Joint Typhoon Warning Center (JTWC) assigned it the numeral identifier 02W the next day, when the storm had deepened its rainbands over its northern and western quadrants. As the storm developed from high ocean heat content (OHC) and outflow towards the equator and North Pole, the JMA and JTWC simultaneously ranked the newborn cyclone a tropical storm at 18:00 UTC, with the former giving it the name Wutip.
Environmental conditions remained favorable for intensification, with the addition of diffluence aloft, allowing Wutip to become a severe tropical storm on February 20 after attaining 10-minute sustained winds of . Wutip further intensified into a typhoon at 18:00 UTC, according to the JMA, as a central dense overcast began to surface. With Wutip moving west-northwestward alongside a subtropical ridge to the north, an eye formation was detected on microwave imagery; on this basis, the JTWC upgraded Wutip to a typhoon early on February 21. Wutip then made a direct hit over Pulusuk during the day while passing near the Mortlock Islands. Significant intensification continued over warm waters as rainbands tightened towards the deepened core. Its motion also mitigated the effects of wind shear, and additionally, a ragged eye emerged on satellite imagery. With rainbands extending , the very compact system then steered in a general northwestward direction, with the eye occasionally appearing throughout February 22. Despite a decrease in sea surface temperatures, low wind shear combined with an excellent poleward outflow channel commenced a period of rapid intensification on February 23. While southwest of Guam, Wutip presented a compact eyewall, and achieved its initial peak intensity at 12:00 UTC; the JMA estimated 10-minute sustained winds of and the lowest barometric pressure of around that time. The JTWC operationally estimated 1-minute sustained winds of , re-classifying Wutip as a super typhoon; however, post-season analysis determined that it had attained winds of 270 km/h (165 mph) two hours prior—making Wutip equivalent to a Category 5 hurricane on the Saffir–Simpson hurricane wind scale.
A moat—a clear ring outside the eyewall—separated the inner core from deep banding features, indicating the onset of an eyewall replacement cycle. During the process, the western edge eroded off the well-defined but warming eyewall as the eye cooled down, signaling a weakening trend. Development was further hampered by dry air intrusion and the storm's entrance to an environment of low OHC; conditions in the upper troposphere however, remained favorable. The moat separating the primary and secondary eyewall then diminished, while the storm became asymmetrical. Upon completion the next day, the eyewall thickened, and its associated convection was replenished and reorganized, becoming well-defined and annular, resuming a trend of rapid intensification. With outflow amplified by a zonal jet stream to the north, Wutip reached a secondary peak intensity at 06:00 UTC of February 25, with 10-minute winds of and atmospheric pressure of assessed by the JMA, and 1-minute winds of assessed by the JTWC, again becoming a Category 5-equivalent super typhoon. Although maintaining deep convective rings, Wutip did not hold this intensity for long, and by the following day, weakened to below super typhoon strength. Cloud tops warmed up as the eye became cloud-filled. The storm drifted northward along a weak point in the subtropical ridge to the east. Following a significant increase in vertical wind shear, Wutip's structure began to rapidly deteriorate, no longer exhibiting an eye.
The storm decelerated from a saddle point as it entered the southern edge of the westerlies, meeting higher levels of unfavorable wind shear. An upper-level trough situated to the west of the storm also reinforced wind shear, further disrupting convection despite the robust outflow. By 12:00 UTC of February 27, Wutip had weakened back into a severe tropical storm. Convection later decreased significantly, prompting the JTWC to downgrade Wutip to tropical storm status. As Wutip turned west-northwestward, deep convection detached from the storm and dissipated, preventing additional development. By February 28, wind shear had completely exposed the well-organized circulation. The JMA downgraded Wutip to a tropical storm at 00:00 UTC, before downgrading it further to a tropical depression six hours later, though the JTWC had already assessed Wutip as a tropical depression at the former time. On the same day, Wutip crossed the 135°E boundary of the Philippine Area of Responsibility, receiving the local name Betty from the PAGASA—the national weather agency for the Philippines. The JTWC discontinued advisories on Wutip, anticipating complete disintegration from unfavorable conditions whereas the JMA continued monitoring the depression until it had dissipated near east of the Philippines on March 2.
Records Wutip was the most powerful typhoon in the month of February on record, surpassing Typhoon Higos of 2015, while also being the longest-lasting typhoon of that month as well. In addition, Wutip is the first and only tropical cyclone in the Northern Hemisphere with Category 5-equivalent winds during the month in history. Only seven Category 4- or Category 5-equivalent typhoons were recorded in the months of January and February since the late 1940s, including three other storms in February that attained Category 4 strength.
Preparations and impact Marshall Islands As a tropical disturbance, Wutip poured heavy rain over the central and southern islands or atolls of the Marshall Islands from February 12 to 18. Majuro reported of 24-hour rain on February 13, while Kwajalein experienced on February 18, which accounted for 73% of the monthly total. Despite this, the Marshall Islands did not receive enough rainfall to alleviate a recent drought, particularly in the northernmost atolls.
Federated States of Micronesia
The National Weather Service (NWS) office in Tiyan, Guam released 3 Special Weather Statements on February 17 and 19 for Chuuk, Pohnpei, and Kosrae States as the pre-Wutip disturbance (later Tropical Depression 02W) approached the island nation. During the latter day, tropical storm warnings were issued for Nukuoro, Lukinor, Losap, and Chuuk Lagoon, and tropical storm watches were placed for Fananu, Puluwat, Ulul, and Satawal; the watches for Puluwat and Satawal were later upgraded to typhoon watches the same day. On February 20, the watches across Puluwat, Fanunu, and Ulul were raised to warnings, and a typhoon watch was issued for Faraulep, after the tropical depression had intensified into Tropical Storm Wutip, with forecasts stating that Wutip would soon strengthen into a typhoon. Satawal's watch became a warning as Nukuoro's advisory was canceled. A tropical storm warning was also added for Faraulep, with a tropical storm watch placed for Woleai. All advisories were later canceled from February 21 to 23. While schools, community halls, and gymnasiums were all used as shelter, some shelters did not provide food and water or proper restrooms.
Wutip passed over Chuuk, Pohnpei and Yap States with winds of more than —equivalent to a Category 2 hurricane—from February 19 to 22, and damaged or destroyed approximately 160 houses and displaced 165 people in Chuuk and Yap. In Pohnpei State, primary and secondary power lines were damaged. Besides having fallen trees, the main island of Pohnpei was entirely left without power before having it restored. The command post of Chuuk State was activated on February 20–21 under an issued executive order, as falling trees, flooding, and damage towards homes were being reported on the 21st. Displaced people were moved to typhoon shelters and also to families residing more inland, away from the shorelines. In Pattiw, 54 homes were destroyed and at least 69 were damaged. Schools were closed down as an effect of major damage as displaced families sheltered in them. In some of the affected islands of Yap, schools also sustained damage. Satellite imagery analysis after the storm revealed extensive damage to vegetation and limited damage to structures of the Northwest Islands.