Typhoon Sinlaku was still bringing wind and rain to the Northern Marianas on Thursday.  At 5:00 a.m. EDT on Thursday the center of Typhoon Sinlaku was located at latitude 18.0°N and longitude 144.6°E which put the center about 90 miles (145 km) west of Alamagan.   Sinlaku was moving toward the north at 7 m.p.h. (11 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. (235 km/h).  The minimum surface pressure was 953 mb.

Typhoon Warnings remain in effect for Rota, Tinian, Saipan, Pagan, Alamagan, and Agrihan.

Typhoon Sinlaku was weakening gradually as it moved just to the west of the Northern Marianas.  The circulation around Sinlaku was pulling drier air into the typhoon.  There were fewer clouds in the regions between the rainbands.  Typhoon Sinlaku also appeared to be in the going through another eyewall replacement cycle.

The circulation around Typhoon Sinlaku was still well organized even though Sinlaku was weakening.  A circular eye with a diameter of 35 miles (55 km) was still visible at the center of Sinlaku’s circulation.  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 in the upper levels of the atmosphere was less than the convergence of mass in the lower levels.  So, the surface pressure was continuing to increase gradually.

The circulation around Typhoon Sinlaku was large.  Winds to typhoon force extended out 90 miles (145 km) from the center of Sinlaku’s circulation.  Winds to tropical storm force extended out 290 miles (470 km) from the center of Typhoon Sinlaku.

The Hurricane Intensity Index (HII) for Typhoon Sinlaku is 20.6.  The Hurricane Size Index (HSI) is 32.7 and the Hurricane Wind Intensity Size Index (HWISI) is 53.2.  Typhoon Sinlaku is similar in intensity to Hurricane Irma when Irma hit Southwest Florida in 2017.  Sinlaku is bigger than Irma was.

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 north-northeast during the next 24 hours.  On its anticipated track, the center of Typhoon Sinlaku will move over the northernmost islands in the Northern Marianas during the nest 24 hours.  Sinlaku will start to move away from the Marianas on Friday.

Typhoon Sinlaku will move through an environment that will become more unfavorable for a strong typhoon during the next 24 hours.  Sinlaku will move over water where the Sea Surface Temperatures are near 26°C.  It will move under the southeastern part of an upper level trough that is southeast of Japan.  The upper level trough will produce southwesterly winds that will blow toward the top of Sinlalu’s circulation.  Those winds will cause the vertical wind shear to increase.  Typhoon Sinlaku will also continue to pull drier air into its circulation.  The drier air will continue to to inhibit the development of new thunderstorms in the rainbands revolving around the center of Sinlaku’s circulation.  The cooler Sea Surface Temperatures, more vertical wind shear and drier air will cause Typhoon Sinlaku to continue to weaken during the next 24 hours.

Typhoon Sinlaku will continue to bring strong winds and heavy rain to the Northern Marianas during the next 24 hours.  Heavy rain is likely to cause flash floods in some locations.

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

Typhoon Sinlaku could also cause a storm surge of up to 10 feet (3 meters).

Typhoon Sinlaku continued to bring strong winds and heavy rain to the Northern Marianas on Wednesday.  At 5:00 a.m. EDT on Wednesday the center of Typhoon Sinlaku was located at latitude 16.2°N and longitude 144.8°E which put the center about 80 miles (130 km) northwest of Saipan.  Sinlaku was moving toward the northwest at 6 m.p.h. (10 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 Warnings remain in effect for Rota, Tinian, Saipan, Pagan, Alamagan, and Agrihan.

A Tropical Storm Warning remains in effect for Guam.

A Typhoon Watch also remains in effect for Guam.

Typhoon Sinlaku completed an eyewall replacement cycle on Wednesday.  A circular eye with a diameter of 35 miles (55 km) was present at the  center of Sinlaku’s circulation.  Bands of showers and thunderstorms were revolving around the core of Typhoon Sinlaku.  Storms near the core of Sinlaku generated upper level divergence that pumped mass away from the typhoon.  The removal of mass in the upper levels of the atmosphere was less than the convergence of mass in the lower levels.  So, the surface pressure was continuing to increase gradually.

The circulation around Typhoon Sinlaku was large.  Winds to typhoon force extended out 75 miles (120 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 23.6.  The Hurricane Size Index (HSI) is 28.3 and the Hurricane Wind Intensity Size Index (HWISI) is 51.9.  Typhoon Sinlaku is similar in size and intensity to Hurricane Wilma when Wilma hit South Florida in 2005.

A weather station at the Guam International Airport recently 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).  There were no recent reports from weather stations on Rota, Tinian, or Saipan.

Typhoon Sinlaku was moving slowly west of the Northern Marianas.  The slow movement was prolonging the period destructive wind and rain in Tinian and Saipan.  Sinlaku was capable of causing major damage.  Prolonged heavy rain is likely to cause flash floods.

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

Typhoon Sinlaku could cause a storm surge of up to 10 feet (3 meters).

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 north-northwest during the next 24 hours.  On its anticipated track, the center of Typhoon Sinlaku will move very slowly away from Tinian and Saipan.  Sinlaku will move parallel of the Northern Marianas on Wednesday.

Typhoon Sinlaku will move through an environment that will be marginally favorable for a strong typhoon during the next 24 hours.  Sinlaku will move over water where the Sea Surface Temperatures are near 28°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 move into a region where the air is drier.  The drier air is likely to inhibit the development of thunderstorms in the northern and western parts of Sinlaku’s circulation.  Typhoon Sinlaku is likely to continue to weaken gradually during the next 24 hours because of the recently completed eyewall replacement cycle and the drier air.

Typhoon Sinlaku battered Tinian and Saipan on Tuesday.  At 11:00 a.m. EDT on Tuesday the center of Typhoon Sinlaku was located at latitude 15.1°N and longitude 145.7°E which put the center about 20 miles (30 km) south of Saipan.   Sinlaku was moving toward the northwest at 5 m.p.h. (8 km/h).   The maximum sustained wind speed was 145 m.p.h. (235 km/h) and there were wind gusts to 175 m.p.h. (285 km/h).  The minimum surface pressure was 930 mb.

Typhoon Warnings are in effect for Rota, Tinian, Saipan, Pagan, Alamagan, and Agrihan.

A Tropical Storm Warning is in effect for Guam.

A Typhoon Watch is also in effect for Guam.

A weather station at the international airport in Saipan reported a sustained wind speed of 82 m.p.h. (132 km) and a wind gust of 130 m.p.h. (210 km/h) as the eyewall of Typhoon Sinlaku passed over it.

Typhoon Sinlaku began an eyewall replacement cycle just before it reached Tinian and Saipan.  A larger, outer eyewall formed around the smaller, original eyewall.  The low level convergence began to be intercepted by the outer eyewall and the original inner eyewall began to weaken.  The weakening of the inner eyewall caused the strongest winds in Typhoon Sinlaku to diminish very gradually.

The remnant of the original inner eyewall was still visible on satellite and radar images of Typhoon Sinlaku.  The larger outer eyewall appeared to be becoming the predominant feature in the core of Sinlaku’s circulation.  Bands of showers and thunderstorms were revolving around the core of Typhoon Sinlaku.  Storms near the core of Sinlaku generated upper level divergence that pumped mass away from the typhoon.  The removal of mass in the upper levels of the atmosphere was less than the strong convergence of mass in the lower levels.  So, the surface pressure was increasing gradually.

The circulation around Typhoon Sinlaku was large.  Winds to typhoon force extended out 75 miles (120 km) from the center of Sinlaku’s circulation.  Winds to tropical storm force extended out 265 miles (425 km) from the center of Typhoon Sinlaku.

The Hurricane Intensity Index (HII) for Typhoon Sinlaku is 29.9.  The Hurricane Size Index (HSI) is 27.4 and the Hurricane Wind Intensity Size Index (HWISI) is 57.3. Typhoon Sinlaku is similar in size and intensity to Hurricane Helene when Helene hit Florida in 2024.

Typhoon Sinlaku started to move more slowly as it began the eyewall replacement cycle.  The slower movement was prolonging the period destructive wind and rain in Tinian and Saipan.  Sinlaku was capable of causing severe damage.  Prolonged heavy rain is likely to cause flash floods.

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

Typhoon Sinlaku could cause a storm surge of up to 13 feet (4 meters).

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 north-northwest during the next 24 hours.  On its anticipated track, the center of Typhoon Sinlaku will move very slowly away from Tinian and Saipan.  Sinlaku will be west of the Marianas on Wednesday.

Typhoon Sinlaku will move into an environment that will be marginally favorable for a strong typhoon during the next 24 hours.  Sinlaku will move over water where the Sea Surface Temperatures are near 28°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 move into a region where the air is drier.  The drier air is likely to inhibit the development of thunderstorms in the northern and western parts of Sinlaku’s circulation.  Typhoon Sinlaku is likely to continue to weaken gradually during the next 24 hours because of the eyewall replacement cycle and the drier air.

The center of Typhoon Sinlaku was nearing Tinian and Saipan on Monday evening.  At 11:00 p.m. EDT on Monday the center of Typhoon Sinlaku was located at latitude 14.5°N and longitude 146.3°E which put the center about 75 miles (120 km) southeast of Saipan.  Sinlaku was moving toward the northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 155 m.p.h. (250 km/h) and there were wind gusts to 190 m.p.h. (305 km/h).  The minimum surface pressure was 919 mb.

Typhoon Warnings are in effect for Rota, Tinian, Saipan, Pagan, Alamagan, and Agrihan.

A Tropical Storm Warning is in effect for Guam.

A Typhoon Watch is also in effect for Guam.

Typhoon Sinlaku weakened just slightly as it neared Tinian and Saipan on Monday evening.  A circular eye with a diameter of 20 miles (32 km) was visible at 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 in the upper levels of the atmosphere was less than the strong convergence of mass in the lower levels.  So, the surface pressure was increasing gradually.

The circulation around Typhoon Sinlaku was large.  Winds to typhoon force extended out 75 miles (120 km) from the center of Sinlaku’s circulation.  Winds to tropical storm force extended out 265 miles (425 km) from the center of Typhoon Sinlaku.

The Hurricane Intensity Index (HII) for Typhoon Sinlaku is 33.3.  The Hurricane Size Index (HSI) is 29.6 and the Hurricane Wind Intensity Size Index (HWISI) is 62.9.  Typhoon Sinlaku is similar in intensity to Hurricane Ian when Ian hit Southwest Florida in 2022.  Sinlaku is bigger than Ian was.

Typhoon Sinlaku will move into an environment that will become a little less favorable for a strong typhoon during the next 24 hours.  Sinlaku will move over water where the Sea Surface Temperatures are near 28°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 move into a region where the air is drier.  The drier air is likely to inhibit the development of thunderstorms in the northern and western parts of Sinlaku’s circulation.  Typhoon Sinlaku is likely to continue to weaken gradually during the next 24 hours because of the drier air.

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, the center of Typhoon Sinlaku will reach Tinian and Saipan in a few hours.

Typhoon Sinlaku will be the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale when it reaches Tinian and Saipan.  Sinlaku will be capable of causing severe damage in Tinian and Saipan.  Typhoon Sinlaku will bring also strong winds and locally heavy rain to Guam, Rota, Pagan, Alamagan, and Agrihan. Heavy rain is likely to cause flash floods in some locations.

A Flash Flood Warning is in effect for Guam.

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

Typhoon Sinlaku could also cause a storm surge of up to 15 feet (4.5 meters) along parts of the coasts of the Marianas.

Typhoon Sinlaku was bearing down on the Marianas on Monday morning.  At 11:00 a.m. EDT on Monday the center of Typhoon Sinlaku was located at latitude 13.3°N and longitude 147.2°E which put the center about 190 miles (335 km) east of Guam.  Sinlaku was moving toward the northwest at 8 m.p.h. (13 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 903 mb.

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

Tropical Storm Warnings are in effect for Guam, Pagan, and Alamagan.

A Typhoon Watch is in effect for Guam.

A Tropical Storm Watch is in effect for Agrihan.

Typhoon Sinlaku was maintaining its intensity as it was bearing down on the Mariana’s on Monday morning.  Sinlaku was the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale.  A circular eye with a diameter of 17 miles (28 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 in the upper levels of the atmosphere was nearly equal to the convergence of mass in the lower levels.  So, the surface pressure was nearly constant.

The circulation around Typhoon Sinlaku was large.  Winds to typhoon force extended out 80 miles (130 km) from the center of Sinlaku’s circulation.  Winds to tropical storm force extended out 290 miles (465 km) from the center of Typhoon Sinlaku.

The Hurricane Intensity Index (HII) for Typhoon Sinlaku is 40.4.  The Hurricane Size Index (HSI) is 28.4 and the Hurricane Wind Intensity Size Index (HWISI) is 68.8.  Typhoon Sinlaku is similar in intensity to Hurricane Maria when Maria was at its peak strength in 2017.  Sinlaku is bigger than Maria was.

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 28°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, the center of Typhoon Sinlaku will be near Tinian and Saipan in less than 24 hours.

Typhoon Sinlaku could be the equivalent of a Category 5 hurricane when it reaches Tinian and Saipan.  Sinlaku will be capable of causing catastrophic damage in Tinian and Saipan.  Typhoon Sinlaku will bring also strong winds and locally heavy rain to Guam, Rota, Pagan, and Alamagan. 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.