Tropical Storm Bavi (

transliterated Transliteration is a type of conversion of a text from one writing system, script to another that involves swapping Letter (alphabet), letters (thus ''wikt:trans-#Prefix, trans-'' + ''wikt:littera#Latin, liter-'') in predictable ways, such as ...

from Vietnamese Ba Vì), known in the

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

as Tropical Storm Betty, was an early-season tropical storm in the

2015 Pacific typhoon season The 2015 Pacific typhoon season was a slightly above average season that produced twenty-seven tropical storms (including two that crossed over from the Eastern/Central Pacific), eighteen typhoons, and nine super typhoons. The season ran throug ...

. The system influenced the

trade winds The trade winds or easterlies are permanent east-to-west prevailing winds that flow in the Earth's equatorial region. The trade winds blow mainly from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere ...

over the Pacific Ocean and was partially responsible for one of the strongest trade wind reversals ever observed. The system was first noted as a tropical disturbance during March 8, 2015, while it was located to the southeast of

Kwajalein Atoll Kwajalein Atoll (; Marshallese language, Marshallese: ) is part of the Marshall Islands, Republic of the Marshall Islands (RMI). The southernmost and largest island in the atoll is named Kwajalein Island, which its majority English-speaking re ...

in the

Marshall Islands The Marshall Islands, officially the Republic of the Marshall Islands, is an island country west of the International Date Line and north of the equator in the Micronesia region of the Northwestern Pacific Ocean. The territory consists of 29 c ...

. Over the next couple of days the system moved north-westwards through the Marshall Islands, before it was classified as a tropical depression during March 10. The system subsequently moved north-westwards and continued to develop further, before it was classified as the third tropical storm of the

and named Bavi by the

Japan Meteorological Agency The Japan Meteorological Agency (JMA; ''気象庁, Kishō-chō'') is a division of the Ministry of Land, Infrastructure, Transport and Tourism dedicated to the Scientific, scientific observation and research of natural phenomena. Headquartered ...

(JMA) during March 11. After continuing its north-westwards movement, the system peaked as a tropical storm during March 14, before it started to weaken as it approached the

Mariana Islands The Mariana Islands ( ; ), also simply the Marianas, are a crescent-shaped archipelago comprising the summits of fifteen longitudinally oriented, mostly dormant volcanic mountains in the northwestern Pacific Ocean, between the 12th and 21st pa ...

. The system subsequently passed over

Guam Guam ( ; ) is an island that is an Territories of the United States, organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. Guam's capital is Hagåtña, Guam, Hagåtña, and the most ...

during the next day, before continuing its west-northwestwards movement as it gradually weakened over the next few days. The system entered the Philippine area of responsibility, where it was named Betty by

PAGASA The Philippine Atmospheric, Geophysical and Astronomical Services Administration (, abbreviated as PAGASA , which means "hope" as in the Tagalog language, Tagalog word ''pag-asa'') is the National Meteorological and Hydrological Services (NMHS ...

during March 17 as the system weakened into a tropical depression. The system was subsequently last noted during March 21, as it dissipated over the Philippines. Bavi and its precursor tropical disturbance impacted eastern

Micronesia Micronesia (, ) is a subregion of Oceania, consisting of approximately 2,000 small islands in the Northwestern Pacific Ocean. It has a close shared cultural history with three other island regions: Maritime Southeast Asia to the west, Poly ...

, with strong to gale-force winds of between , reported on various atolls in the Marshall Islands. Considerable damage was reported on the islet of

Ebeye Ebeye ( ; Marshallese: , or in older orthography, ; locally, , , after the English pronunciation) is the most populous island of Kwajalein Atoll in the Marshall Islands, and the second most populated island in the Marshall Islands. It is a cen ...

, on the main atoll of Kwajalein, a small amount of tree damage was reported, while several old steel structures were made too dangerous to use. Overall damages in the Marshall Islands were estimated at US$2.1 million, while a fishing vessel and its crew of nine were reported missing during March 12. Bavi and its precursor also had severe impacts in

Kiribati Kiribati, officially the Republic of Kiribati, is an island country in the Micronesia subregion of Oceania in the central Pacific Ocean. Its permanent population is over 119,000 as of the 2020 census, and more than half live on Tarawa. The st ...

. After impacting Eastern Micronesia, Bavi approached the Mariana Islands, with its circulation passing over Guam during March 15, where it caused the highest waves to be recorded on the island in a decade. Bavi also impacted the

Northern Mariana Islands The Northern Mariana Islands, officially the Commonwealth of the Northern Mariana Islands (CNMI), is an Territories of the United States, unincorporated territory and Commonwealth (U.S. insular area), commonwealth of the United States consistin ...

of Rota,

Tinian Tinian () is one of the three principal islands of the Commonwealth of the Northern Mariana Islands (CNMI). Together with uninhabited neighboring Aguiguan, it forms Tinian Municipality, one of the four constituent municipalities of the Northern ...

and

Saipan Saipan () is the largest island and capital of the Northern Mariana Islands, an unincorporated Territories of the United States, territory of the United States in the western Pacific Ocean. According to 2020 estimates by the United States Cens ...

, where power outages were reported and five houses were destroyed. Total property damages within the Mariana Islands were estimated at around US$150 thousand.

Meteorological history

During the opening days of March 2015, a major

westerly wind burst A westerly wind burst (WWB) or westerly wind event (WWE)https://glossary.ametsoc.org/wiki/Westerly_wind_burst is a phenomenon commonly associated with El Niño events, whereby the typical east-to-west trade winds across the equatorial Pacific shift ...

occurred, which subsequently contributed to the development of the 2014-16 El Nino event and the development of twin tropical cyclones in the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

on both sides of the equator. The first tropical cyclone became Severe Tropical Cyclone Pam within the South Pacific Ocean and impacted various parts of

Melanesia Melanesia (, ) is a subregion of Oceania in the southwestern Pacific Ocean. It extends from New Guinea in the west to the Fiji Islands in the east, and includes the Arafura Sea. The region includes the four independent countries of Fiji, Vanu ...

including the

Solomon Islands Solomon Islands, also known simply as the Solomons,John Prados, ''Islands of Destiny'', Dutton Caliber, 2012, p,20 and passim is an island country consisting of six major islands and over 1000 smaller islands in Melanesia, part of Oceania, t ...

and

Vanuatu Vanuatu ( or ; ), officially the Republic of Vanuatu (; ), is an island country in Melanesia located in the South Pacific Ocean. The archipelago, which is of volcanic origin, is east of northern Australia, northeast of New Caledonia, east o ...

. The second tropical cyclone was first noted by the United States

Joint Typhoon Warning Center The Joint Typhoon Warning Center (JTWC) is a joint United States Navy – United States Air Force command in Pearl Harbor, Hawaii. The JTWC is responsible for the issuing of tropical cyclone warnings in the North-West Pacific Ocean, South P ...

(JTWC) as a tropical disturbance during March 8, while it was located about to the southeast of

in the

. The disturbance consisted of a large area of

atmospheric convection Atmospheric convection is the vertical transport of heat and moisture in the atmosphere. It occurs when warmer, less dense air rises, while cooler, denser air sinks. This process is driven by parcel-environment instability, meaning that a "par ...

, which was starting to wrap into the system's developing low level circulation centre. The disturbance was also thought to be in a favourable environment for further development at this time, with low vertical wind shear and a good outflow towards the equator. Over the next couple of days the system moved north-westwards through the

and into a marginal environment for further development, with moderate vertical wind shear being partially offset by the system's outflow. During March 10, the

subsequently started monitoring the disturbance as a tropical depression, while it was located about to the northeast of

Bairiki Bairiki is a town located in South Tarawa, Kiribati. It is crucial to the country's political and administrative structure as several governmental organizations and diplomatic missions are situated there. Landmarks The State House, a building ...

. Over the next day, the system moved north-westwards and gradually developed further, before the JMA reported that the system had developed into a tropical storm and named it Bavi during March 11. Later that day as the system's low level circulation centre continued to consolidated and deep convection wrapped into it, the JTWC initiated advisories and designated the system as 03W. The system subsequently continued to gradually intensify as it moved westwards, around the southern periphery of a subtropical ridge of high pressure located to the northwest of the system. During March 14, the system peaked as a tropical storm with the JMA reporting 10-minute sustained winds of 85 km/h (50 mph), while the JTWC reported 1-minute sustained winds of 95 km/h (60 mph). By this time the system was approaching the Mariana islands and had started to weaken, with system's low level circulation becoming partially exposed and displaced from the atmospheric convection. As a result of this the system's low level circulation passed over

during March 15, while convection associated with the system passed over the Northern Mariana islands. Over the next couple of days the system moved westwards and continued to weaken, before it weakened into a tropical depression during March 17, as it moved into the

Philippine area of responsibility The Philippine Area of Responsibility (PAR) is an area in the Northwestern Pacific where PAGASA, the Philippines' national meteorological agency, monitors weather occurrences. Significant weather disturbances, specifically typhoons that enter o ...

where it was named Betty by

. The JTWC stopped monitoring Bavi during March 19, after the system had weakened into a tropical disturbance, however, the JMA continued to monitor the system as a tropical depression, until it dissipated within the Philippines, during March 21.

Preparations and impact

Tropical Storm Bavi and its precursor were reported to have caused severe impacts in Kiribati. Tropical Storm Bavi impacted various atolls within

, while the system's large wind field generated large waves, which were problematic in the Marshall Islands and the Mariana islands. The system also influenced the Pacific

and with Severe Tropical Cyclone Pam, caused one of the strongest trade wind reversals that had been observed on record. Bavi and its precursor tropical disturbance impacted eastern Micronesia between March 9–13, with gusty winds and high seas reported throughout the

. A pressure gradient between Bavi and an area of high pressure, generated strong to gale-force winds of between on various atolls. As a result, various tropical storm watches and warnings were issued for parts of the Marshall Islands, including the coral atolls of Ujae and Ailinglaplap. On the 15 islands that make up the atoll of Ujae, a significant period of strong winds were reported, which lead to breadfruit trees being destroyed and several houses blown over. Across the

, total damages amounted to over US$1 million, with considerable damage reported on the islet of

. On the main island of Kwajalein, a small amount of tree damage was reported, while several old steel structures were made too dangerous to use. At the missile defense test range on the island, a 3-day rainfall total of was reported between March 9–11. On the islet of Ebeye located about to the north of Kwajalein, high surf caused some

coastal flooding Coastal flooding occurs when dry and low-lying land is submerged (flooded) by seawater. The range of a coastal Flood, flooding is a result of the elevation of floodwater that penetrates the inland which is controlled by the topography of the coas ...

while gale-force winds damaged structures with tin roofs and plywood walls. Bavis's large waves combined with the high tide caused flooding on various islets of the atoll of

Majuro Majuro (; Marshallese language, Marshallese: ' ) is the Capital city, capital and largest city of the Marshall Islands. It is also a large coral atoll of 64 islands in the Pacific Ocean. It forms a legislative district of the Ratak Chain, Ratak ( ...

. Within the atoll a yacht struck a reef during March 10, while the fishing vessel ''Clearwater 2'' and its crew of nine were reported missing during March 12, after they became overdue at their destination port. A search and rescue mission was subsequently launched with various good samaritan vessels and two aircraft from the United States Coast Guard and Navy helping to look for the vessel. The search effort subsequently found debris from the ship in various locations along the track taken by Bavi, including to the east of Majuro and southeast of Kwajalein. Total damages to property within the Marshall Islands were estimated at US$2.1 million, while the total crop damage was estimated at US$100 thousand. After leaving Eastern Micronesia, Bavi continued to move westwardsand threatened to impact the

as a typhoon. As a result, the Guam Weather Forecast Office issued a typhoon watch and a

tropical storm warning Tropical cyclone warnings and watches are alerts issued by national weather forecasting bodies to coastal areas threatened by the imminent approach of a tropical cyclone of tropical storm or hurricane intensity. They are notices to the local pop ...

for Guam, Rota,

and

during March 13. The islands were also placed in Tropical Cyclone Condition of Readiness 1 by Governors

Eddie Calvo Edward Jerome Baza Calvo (born August 29, 1961) is an American politician who served as the eighth governor of Guam from January 3, 2011 to January 7, 2019. A member of the Republican Party, Calvo was a five-term Senator within the Legislature ...

, Eloy Inos and Rear Admiral Bette Bolivar. The Guam Waterworks Authority advised residents on the island stock up on water ahead of the system, in case Bavi disrupted the island's water service. United Airlines, Cape Air and United Express all cancelled flights that departed from Guam, while schools were shut on the island during March 15. However, as Bavi approached the islands, upper level wind shear caused the system to decouple and start to gradually weaken. Bavi's circulation subsequently passed over Guam during March 15, with winds on the island barely reaching gale force on the island. Within Guam, sporadic power outages and minor tree damage were reported, while waves on the uninhabited northeastern coast of Guam reached and were the highest waves recorded on the island in a decade. A band of showers associated with the system and a

pressure gradient In hydrodynamics and hydrostatics, the pressure gradient (typically of air but more generally of any fluid) is a physical quantity that describes in which direction and at what rate the pressure increases the most rapidly around a particular locat ...

, between Bavi and an area of high pressure, brought winds of up to to

and

. As a result, several trees and power lines were brought down across the islands, which resulted in Saipan having sporadic power outages and temporarily losing all electric. Around 65 homes which were primarily constructed with wood and tin were affected by the winds, with 5 destroyed while a further 52 sustained some damage. The local Red Cross chapter subsequently provided tarpaulins, cleaning materials and over $25,000 in assistance to 252 people, while total property damages within the Mariana Islands were estimated at around US$150 thousand.

References

External links

JMA General Information
of Tropical Storm Bavi (1503) from Digital Typhoon
JMA Best Track Data
of Tropical Storm Bavi (1503) JTWC Best Track Data
of Tropical Storm 03W (Bavi)-->
03W.BAVI
from the U.S. Naval Research Laboratory {{DEFAULTSORT:Bavi (2015) 2015 Pacific typhoon season Western Pacific tropical storms Typhoons in Guam Typhoons in the Marshall Islands Typhoons in the Northern Mariana Islands March 2015 in the United States Tropical cyclones in Kiribati Bavi

Meteorological history

Preparations and impact

See also

References

External links