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Typhoon Sinlaku Intensifies to Equivalent of Cat. 5 Hurricane

Typhoon Sinlaku intensified to the equivalent of a category 5 hurricane on the Saffir-Simpson Scale on Sunday.  At 11:00 a.m. EDT on Sunday the center of Typhoon Sinlaku was located at latitude 11.4°N and longitude 149.9°E which put the center about 410 miles (660 km) east-southeast of Guam.  Sinlaku was moving toward the north-northwest at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 175 m.p.h. (285 km/h) and there were wind gusts to 205 m.p.h. (335 km/h).  The minimum surface pressure was 902 mb.

Typhoon Warnings were in effect for Rota, Tinian, and Saipan.

A Tropical Storm Warning was in effect for Guam.

A Typhoon Watch was also in effect for Guam.

Typhoon Sinlaku rapidly intensified to the equivalent of a Category 5 hurricane on Sunday.  A circular eye with a diameter of 20 miles (32 km) was as the center of Sinlaku’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Typhoon Sinlaku.  Storms near the center of Sinlaku generated upper level divergence that pumped mass away from the typhoon.  The removal of mass caused the surface pressure to decrease.

The circulation around Typhoon Sinlaku was large.  Winds to typhoon force extended out 60 miles (95 km) from the center of Sinlaku’s circulation.  Winds to tropical storm force extended out 275 miles (445 km) from the center of Typhoon Sinlaku.

The Hurricane Intensity Index (HII) for Typhoon Sinlaku is 40.4.  The Hurricane Size Index (HSI) is 21.3 and the Hurricane Wind Intensity Size Index (HWISI) is 61.7.  Typhoon Sinlaku is similar in size and intensity to Hurricane Maria when Maria was at its peak strength in 2017.

Typhoon Sinlaku will move through an environment favorable for a very powerful typhoon during the next 24 hours.  Sinlaku will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the middle of an upper level ridge that is over the Western North Pacific Ocean.  The upper level winds are weak near the middle of the ridge and there will be little vertical wind shear.  Typhoon Sinlaku is likely to maintain its intensity during the next 24 hours unless an eyewall replacement cycle occurs.  Sinlaku could weaken if the inner end of a rainband wraps around the existing eye and eyewall.  If concentric eyewalls form, then an eyewall replacement cycle would cause Typhoon Sinlaku to weaken.

Typhoon Sinlaku will move around the western part of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer Sinlaku toward the northwest during the next 24 hours.  On its anticipated track, Typhoon Sinlaku will approach the Marianas in less than 35 hours.

Typhoon Sinlaku will be the equivalent of a major hurricane when it approaches the Marianas.  Sinlaku will bring very strong winds and locally heavy rain to Guam, Rota, Tinian, and Saipan.   Heavy rain is likely to cause flash floods in some locations.

Flood Watches are in effect for Guam, Rota, Tinian, and Saipan.

Typhoon Sinlaku could also cause a storm surge of up to 17 feet (5.1 meters) along parts of the coasts of the Marianas.

Typhoon Sinlaku Intensifies to Equivalent of a Major Hurricane

Typhoon Sinlaku intensified to the equivalent of a major hurricane as it moved southeast of the Marianas on Saturday evening.  At 11:00 p.m. EDT on Saturday the center of Typhoon Sinlaku was located at latitude 10.2°N and longitude 151.0°E which put the center about 505 miles (815 km) east-southeast of Guam.  Sinlaku was moving toward the north-northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 155 m.p.h. (250 km/h).  The minimum surface pressure was 944 mb.

Typhoon Watches are in effect for Guam, Rota, Tinian, and Saipan.

Typhoon Sinlaku continued to strengthen on Saturday evening as it moved toward the southern Marianas.  A circular eye with a diameter of 20 miles (32 km) was as the center of Sinlaku’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Typhoon Sinlaku.  Storms near the center of Sinlaku generated upper level divergence that pumped mass away from the typhoon.  The removal of mass caused the surface pressure to decrease.

The circulation around Typhoon Sinlaku was large.  Winds to typhoon force extended out 60 miles (95 km) from the center of Sinlaku’s circulation.  Winds to tropical storm force extended out 250 miles (400 km) from the center of Typhoon Sinlaku.

The Hurricane Intensity Index (HII) for Typhoon Sinlaku was 23.6.  The Hurricane Size Index (HSI) was 21.2 and the Hurricane Wind Intensity Size Index (HWISI) was 44.8.

Typhoon Sinlaku will move through an environment favorable for intensification during the next 24 hours.  Sinlaku will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the middle of an upper level ridge that is over the Western North Pacific Ocean.  The upper level winds are weak near the middle of the ridge and there will be little vertical wind shear.  Typhoon Sinlaku will intensify during the next 24 hours.  Sinlaku could intensify rapidly at times.  Typhoon Sinlaku could strengthen to the equivalent of a Category 5  hurricane on the Saffir-Simpson Scale during the next 36 hours.

Typhoon Sinlaku will move around the southwestern part of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer Sinlaku toward the northwest during the next 24 hours. On its anticipated track, Typhoon Sinlaku will approach the southern Marianas in less than 48 hours.

Typhoon Sinlaku will be the equivalent of a major hurricane when it approaches the southern Marianas.  Sinlaku will bring very strong winds and locally heavy rain to Guam, Rota, Tinian, and Saipan.  Heavy rain is likely to cause flash floods in some locations.

Flood Watches are in effect for Guam, Rota, Tinian, and Saipan.

Typhoon Sinlaku could also cause a storm surge of up to 14 feet (4.3 meters) along parts of the coasts of the southern Marianas.

Sinlaku Causes Typhoon Watch for Guam

The threat posed by Typhoon Sinlaku caused a Typhoon Watch to be issued for Guam, Rota, Tinian, and Saipan on Saturday.  At 11:00 a.m. EDT on Saturday the center of Typhoon Sinlaku was located at latitude 9.2°N and longitude 150.9°E which put the center about 535 miles (865 km) southeast of Guam.  Sinlaku was moving toward the northwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 965 mb.

Typhoon Watches are in effect for Guam, Rota, Tinian, and Saipan.

Typhoon Sinlaku continued to strengthen on Saturday as it moved toward the southern Marianas.  A small circular eye was as the center of Sinlaku’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Typhoon Sinlaku.  Storms near the center of Sinlaku generated upper level divergence that pumped mass away from the typhoon.  The removal of mass caused the surface pressure to decrease.

The size of the circulation around Typhoon Sinlaku continued to increase on Saturday.  Winds to typhoon force extended out 50 miles (80 km) from the center of Sinlaku’s circulation.  Winds to tropical storm force extended out 250 miles (400 km) in the northeastern quadrant of Typhoon Sinlaku.  Winds to tropical storm force extended out 165 miles (265 km) in the other quadrants of Sinlaku’s circulation.

Typhoon Sinlaku will move through an environment favorable for intensification during the next 24 hours.  Sinlaku will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the middle of an upper level ridge that is over the Western North Pacific Ocean.  The upper level winds are weak near the middle of the ridge and there will be little vertical wind shear.  Typhoon Sinlaku will intensify during the next 24 hours.  Sinlaku could intensify rapidly at times. Typhoon Sinlaku is likely to strengthen to the equivalent of a major hurricane during the weekend.

Typhoon Sinlaku will move around the southwestern part of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer Sinlaku toward the northwest during the next 24 hours.  On its anticipated track, Typhoon Sinlaku will move toward the southern Marianas.  Sinlaku will approach Guam in 48 hours.

Typhoon Sinlaku will be the equivalent of a major hurricane when it approaches the southern Marianas.  Sinlaku could bring very strong winds and locally heavy rain to Guam, Rota, Tinian, and Saipan.  Heavy rain is likely to cause flash floods in some locations.  Typhoon Sinlaku could cause a storm surge of up to 13 feet (4 meters) along parts of the coasts of the southern Marianas.

Tropical Storm Man-yi Brings Gusty Winds to Guam

Tropical Storm Man-yi brought gusty winds to Guam on Tuesday.  At 4:00 p.m. EST on Tuesday the center of Tropical Storm Man-yi was located at latitude 12.5°N and longitude 144.4°E which put the center about 40 miles (65 km) southeast of Guam.  Man-yi was moving toward the southwest at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 994 mb.

Tropical Storm Warnings were in effect for Guam, Rota, Tinian, and Saipan.

Tropical Storm Man-yi brought gusty wind to Guam and the Marianas on Tuesday.  A weather station at the Guam International Airport reported a sustained wind speed of 30 m.p.h. (50 km/h) and a wind gust of 48 m.p.h. (77 km/h) on Tuesday.

The circulation around Tropical Storm Man-yi was somewhat disorganized.  There were not many thunderstorms near the center of Man-yi’s circulation.  Thunderstorms were occurring in bands in the southern side of the center of Tropical Storm Man-yi.  Bands in the northern side of Man-yi’s circulation consisted primarily of showers and lower clouds.

The circulation around Tropical Storm Man-yi was small.  Winds to tropical storm force extended out 85 miles (135 km) from the center of Man-yi’s circulation.

Tropical Storm Man-yi will move through an environment somewhat favorable for intensification during the next 24 hours.  Man-yi will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the southern side of an upper level ridge over the Western North Pacific Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Man-yi’s circulation.  Those winds will cause some vertical wind shear. The wind shear will inhibit intensification, but the shear may not be enough to prevent intensification. Tropical Storm Man-yi could intensify during the next 24 hours.

Tropical Storm Man-yi will move around the southern side of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Man-yi toward the west during the next 24 hours.  On its anticipated track, Tropical Storm Man-yi will move away from the Marianas.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Usagi strengthened east of the Philippines, Tropical Depression Yinxing moved inland over Vietnam, and Tropical Storm Toraji was spinning over the South China Sea southeast of Hong Kong.

At 4:00 p.m. EST on Tuesday the center of Tropical Storm Usagi was located at latitude 15.0°N and longitude 128.3°E which put the center about 530 miles (850 km) east of Manila, Philippines.  Usagi was moving toward the west at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 987 mb.

At 10:00 a.m. EST on Tuesday the center of Tropical Depression Yinxing was located at latitude 14.0°N and longitude 108.2°E which put the center about 145 miles (235 km) south of Da Nang, Vietnam.  Yinxing was moving toward the west at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1004 mb.

At 4:00 p.m. EST on Tuesday the center of Tropical Storm Toraji was located at latitude 20.1°N and longitude 116.8°E which put the center about 245 miles (395 km) southeast of Hong Kong.  Toraji was moving toward the west-northwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 997 mb.

Tropical Storm Usagi Forms East of the Philippines

Tropical Storm Usagi formed over the Western North Pacific Ocean east of the Philippines on Monday.  At 4:00 p.m. EST on Monday the center of Tropical Storm Usagi was located at latitude 13.0°N and longitude 134.2°E which put the center about 945 miles (1525 km) east of Manila, Philippines.  Usagi was moving toward the west at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 991 mb.

Another tropical storm formed east of the Philippines on Monday.  Former Tropical Depression Twentyseven-W strengthened and the Japan Meteorological Agency designated the system as Tropical Storm Usagi.  More thunderstorms formed near the center of Usagi’s circulation.  However, the distribution of thunderstorms in Tropical Storm Usagi was asymmetrical.  Many of the thunderstorms were occurring in bands in the western half of Usagi’s circulation.  Bands in the eastern half of Tropical Storm Usagi consisted primarily of showers and lower clouds.  Storms near the center of Usagi generated upper level divergence that pumped mass away to the west of the tropical storm.

The circulation around Tropical Storm Usagi was small.  Winds to tropical storm force extended out 50 miles (80 km) from the center of Usagi’s circulation.

Tropical Storm Usagi will move through an environment favorable for intensification during the next 24 hours.  Usagi will move over water where the Sea Surface Temperatures are near 30°C.   It will move under the southern side of an upper level ridge over the Western North Pacific Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Usagi’s circulation.  Those winds will cause some vertical wind shear.  The wind shear will inhibit intensification, but the shear will not be enough to prevent intensification.  Tropical Storm Usagi will intensify during the next 24 hours.  Usagi could strengthen to a typhoon on Tuesday.

Tropical Storm Usagi will move around the southern side of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Usagi toward the west-northwest during the next 24 hours.  On its anticipated track, Tropical Storm Usagi will move toward the Philippines.

Elsewhere over the Western North Pacific Ocean, former Typhoon Toraji weakened as it moved away from the Philippines, Tropical Storm Yinxing approached the coast of Vietnam, Tropical Storm Watches were issued in the Marianas for Tropical Storm Man-yi.

At 4:00 p.m. EST on Monday the center of Tropical Storm Toraji was located at latitude 18.5°N and longitude 118.7°E which put the center about 420 miles (675 km) southeast of Hong Kong.  Toraji was moving toward the west-northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 985 mb.

At 4:00 p.m. EST on Monday the center of Tropical Storm Yinxing was located at latitude 14.6°N and longitude 109.6°E which put the center about 130 miles (210 km) southeast of Da Nang, Vietnam.  Yinxing was moving toward the south-southwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 999 mb.

At 4:00 p.m. EST on Monday the center of Tropical Storm Man-yi was located at latitude 14.0°N and longitude 150.5°E which put the center about 430 miles (695 km) east of Guam.  Man-yi was moving toward the west-southwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 992 mb.

Tropical Storm Watches were in effect for Guam, Rota, Tinian and Saipan.

Tropical Storm Bebinca Forms Near Guam

Tropical Storm Bebinca formed near Guam on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Bebinca located at latitude 13.6°N and longitude 144.0°E which put the center about 20 miles (30 km) southwest of Guam.  Bebinca was moving toward the west-northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 999 mb.

Tropical Storm Warnings were in effect for the coastal waters of Guam, Rota, Tinian and Saipan.

A low pressure system near Guam strengthened on Tuesday and the Japan Meteorological Agency designated the system as Tropical Storm Bebinca.  Bebinca brought wind and rain to the Marianas.  A weather station at Guam International Airport (PGUM) reported a sustained wind speed of 28 m.p.h. (45 km/h) and a wind gust of 45 m.p.h. (73 km/h).

The circulation around Tropical Storm Bebinca was exhibiting more organization on Tuesday afternoon.  More thunderstorms developed near the center of Bebinca’s circulation.  Thunderstorms also formed in bands in the eastern side of Tropical Storm Bebinca.  Bands in the western side of Bebinca’s circulation consisted primarily of showers and lower clouds.  Storms near the center of Bebinca generated upper level divergence that pumped mass away from the tropical storm.  The removal of mass caused the pressure to decrease.

The distribution of winds speeds in Tropical Storm Bebinca was asymmetrical.  Winds to tropical storm force extended out 100 miles (160 km) in the northeastern quadrant of Bebinca’s circulation.  Winds to tropical storm force only extended out 25 miles (40 km) in the other parts of Tropical Storm Bebinca.

Tropical Storm Bebinca will move through an environment favorable for intensification during the next 24 hours.  Bebinca will move over water where the Sea Surface Temperatures are near 30°C.   It will move under the western part of an upper level ridge over the Western North Pacific Ocean.  The upper level ridge will produce southerly winds that will blow toward the top of Bebinca’s circulation.  Those winds will cause some vertical wind shear.  The wind shear will inhibit intensification, but the shear will not be enough to prevent intensification.  Tropical Storm Bebinca will intensify during the next 24 hours.  Bebinca is likely to strengthen to a typhoon later this week.

Tropical Storm Bebinca will move around the southwestern part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Bebinca toward the northwest during the next 24 hours.  On its anticipated track, Tropical Storm Bebinca will move west of the Marianas.  Bebinca could approach the Ryukyu Islands by the end of the week.

Typhoon Bolaven Rapidly Intensifies to Equivalent of Cat. 5 Hurricane

Typhoon Bolaven rapidly intensified to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale on Tuesday evening. At 11:00 p.m. EDT on Tuesday the center of Typhoon Bolaven was located at latitude 17.5°N and longitude 143.8°E which put it about 245 miles (390 km) north-northwest of Guam. Bolaven was moving toward the north-northwest at 14 m.p.h. (22 km/h). The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 185 m.p.h. (295 km/h). The minimum surface pressure was 920 mb.

Typhoon Warnings were in effect for Rota, Tinian and Saipan. Tropical Storm Warnings were in effect for Agrihan, Pagan and Alamagan.

Typhoon Bolaven rapidly intensified to the equivalent of a Category 5 hurricane west of the Marianas on Tuesday evening. A small circular eye with a diameter of 14 miles (22 km) was at the center of Bolaven’s circulation. The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Bolaven. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The circulation around Typhoon Bolaven was very symmetrical. Winds to typhoon force extended out 25 miles (40 km) from the center of Bolaven’s circulation. Winds to tropical storm force extended out 185 miles (295 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Bolaven was 35.0. The Hurricane Size Index (HSI) was 11.5 and the Hurricane Wind Intensity Size Index (HWISI) was 46.5.

Typhoon Bolaven will move through an environment favorable for intensification during the next 24 hours. Bolaven will move over water where the Sea Surface Temperatures are near 30°C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Typhoon Bolaven could continue to intensify during the next 24 hours. If the inner end of a rainband wraps around the existing eye and eyewall, then concentric eyewalls could form. If concentric eyewalls form, then an eyewall replacement cycle could cause Typhoon Bolaven to weaken.

Typhoon Bolaven will move around the western part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Bolaven toward the north-northwest during the next 24 hours. On its anticipated track, the Typhoon Bolaven will stay west of the Marianas during the next 24 hours.

Typhoon Bolaven Rapidly Intensifies to Equivalent of a Major Hurricane

Typhoon Bolaven rapidly intensified to the equivalent of a major hurricane over the Western North Pacific Ocean north of Guam on Tuesday. At 5:00 p.m. EDT on Tuesday the center of Typhoon Bolaven was located at latitude 16.4°N and longitude 144.3°E which put it about 100 miles (160 km) northwest of Tinian. Bolaven was moving toward the north-northwest at 11 m.p.h. (17 km/h). The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (230 km/h). The minimum surface pressure was 959 mb.

A Typhoon Warning was in effect for Rota, Tinian and Saipan. A Typhoon Watch was in effect for Guam. A Tropical Storm Warning was in effect for Guam.

Typhoon Bolaven brought strong winds and heavy rain to Guam, Rota, Tinian and Saipan. The center of Bolaven passed between Rota and Tinian and the strongest winds likely occurred in those places. A weather station in Saipan reported a sustained wind speed of 49 m.p.h. (79 km/h) and a wind gust of 68 m.p.h. (110 km/h). A weather station at Guam International Airport reported a sustained wind speed of 32 m.p.h. (52 km/h) and a wind gust of 46 m.p.h. (74 km/h). That weather station also measured 4.54 inches (115.3 mm) of rain.

Typhoon Bolaven began to intensify rapidly as it moved west of the Marianas. A small circular eye with a diameter of 14 miles (22 km) developed at the center of Bolaven’s circulation. The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Bolaven. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The size of the circulation around Typhoon Bolaven increased when it intensified on Tuesday. Winds to typhoon force extended out 25 miles (40 km) from the center of Bolaven’s circulation. Winds to tropical storm force extended out 185 miles (295 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Bolaven was 20.6. The Hurricane Size Index (HSI) was 11.5 and the Hurricane Wind Intensity Size Index (HWISI) was 32.1.

Typhoon Bolaven will move through an environment favorable for intensification during the next 24 hours. Bolaven will move over water where the Sea Surface Temperatures are near 30°C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Typhoon Bolaven will intensify during the next 24 hours. Bolaven could intensify rapidly at times. Typhoon Bolaven could strengthen to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale.

Typhoon Bolaven will move around the western part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Bolaven toward the north-northwest during the next 24 hours. On its anticipated track, the Typhoon Bolaven will stay west of the Marianas during the next 24 hours.

Bolaven Strengthens to a Typhoon East of Guam

Former Tropical Storm Bolaven strengthened to a typhoon east of Guam on Monday night. At 11:00 p.m. EDT on Monday the center of Typhoon Bolaven was located at latitude 14.0°N and longitude 146.0°E which put it about 110 miles (175 km) east of Guam. Bolaven was moving toward the northwest at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h). The minimum surface pressure was 990 mb.

A Typhoon Warning was in effect for Rota, Tinian and Saipan. A Typhoon Watch was in effect for Guam. A Tropical Storm Warning was in effect for Guam.

Former Tropical Storm Bolaven strengthened to a typhoon as it neared the Marianas on Monday night. A circular eye formed at the center of Bolaven’s circulation. The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Bolaven. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The size of the circulation around Bolaven increased when it intensified on Monday. Winds to typhoon force extended out 35 miles (55 km) from the center of Bolaven’s circulation. Winds to tropical storm force extended out 140 miles (220 km) from the center of circulation.

Typhoon Bolaven will move through an environment favorable for intensification during the next 24 hours. Bolaven will move over water where the Sea Surface Temperatures are near 30°C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Typhoon Bolaven will intensify during the next 24 hours. Bolaven could intensify rapidly at times.

Typhoon Bolaven will move around the southwestern part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Bolaven toward the northwest during the next 24 hours. On its anticipated track, the center Typhoon Bolaven will pass near Rota in a few hours.

Typhoon Bolaven will bring strong winds and heavy rain to Rota, Tinian and Saipan. The strongest winds are likely to occur in Rota and Tinian. Bolaven will also produce gusty winds and heavy rain in Guam. The strong winds will be capable of causing damage and electricity outages are likely. Heavy rain will cause flash floods in some locations.

Tropical Storm Bolaven Moves Toward the Marianas

Tropical Storm Bolaven moved toward the Marianas on Sunday night. At 11:00 p.m. EDT on Sunday the center of Tropical Storm Bolaven was located at latitude 11.1°N and longitude 149.9°E which put it about 410 miles (660 km) east-southeast of Guam. Bolaven was moving toward the west-northwest at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 992 mb.

A Typhoon Watch was in effect for Guam, Rota, Tinian and Saipan. A Tropical Storm Warning was also in effect for Guam.

Tropical Storm Bolaven strengthened on Sunday. The inner end of a rainband wrapped around the center of Bolaven’s circulation. Bands of showers and thunderstorms revolved around the center of circulation. Storms near the center generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 70 miles (100 km) from the center of Bolaven.

Tropical Storm Bolaven will move through an environment favorable for intensification during the next 24 hours. Bolaven will move over water where the Sea Surface Temperatures are near 30°C. It will move under the southern part of an upper level ridge over the Western North Pacific Ocean. The ridge will produce easterly winds that will blow toward the top of Bolaven’s circulation. Those winds will cause some vertical wind shear, but the wind shear will not be enough to prevent intensification. Tropical Storm Bolaven is likely to intensify to a typhoon during the next 24 hours.

Tropical Storm Bolaven will move around the southwestern part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Bolaven toward the northwest during the next 24 hours. On its anticipated track Tropical Storm Bolaven will move closer to the Marianas. Bolaven could reach the Marianas in less than 36 hours. Bolaven will very likely be a typhoon when it reaches the Marianas.

Elsewhere over the Western North Pacific Ocean, former Typhoon Koinu made landfall on the coast of China west of Hong Kong on Sunday. At 11:00 p.m. EDT on Sunday the center of Tropical Storm Koinu was located at latitude 21.5°N and longitude 112.9°E which put it about 75 miles (120 km) west-southeast of Hong Kong. Koinu was moving toward the west at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h). The minimum surface pressure was 988 mb.