Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Typhoon Maria Makes Landfall in China

The center of Typhoon Maria made landfall Lianjiang, China on Tuesday night.  At 11:00 p.m. EDT on Tuesday the center of Typhoon Maria was located at latitude 26.7°N and longitude 119.3°E which put it near Ningde, China.  Maria was moving toward the west-northwest at 22 m.p.h. (35 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 135 m.p.h. (215 km/h).  The minimum surface pressure was 952 mb.

Two concentric eyewalls formed at the center of Typhoon Maria before it made landfall on the coast of China.  The inner eyewall was dissipating, but it still existed at the time of landfall.  The outer eyewall started to contract prior to landfall.  Winds to typhoon force extended out about 65 miles (105 km) from the center of circulation in the part of the circulation over water.  Winds to tropical storm force extended out about 235 miles (380 km) from the center in the part of the circulation over water.

Typhoon Maria brought strong winds and a storm surge to the coast of Zhejiang province when it made landfall.  Maria was also dropping heavy rain and flash flooding could occur.  Typhoon Maria was moving around the western end of a subtropical ridge over the Western North Pacific Ocean.  The ridge was steering Maria toward the west-northwest, but the typhoon is likely to turn more toward the northwest when it moves farther inland.  Typhoon Maria will weaken as it moves inland over eastern China, but it will still drop heavy rain and flooding will be a significant risk.

Typhoon Maria Drops Heavy Rain on Taiwan

Typhoon Maria dropped heavy rain on Taiwan on Tuesday after it brought wind and rain to the southern Ryukyu Islands.  At 5:00 p.m. EDT the center of Typhoon Maria was located at latitude 26.5°N and longitude 121.4°E which put it about 85 miles (135 km) north-northeast of Taipei, Taiwan.  Maria was moving toward the west-northwest at 22 m.p.h. (35 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 949 mb.

A primary rainband wrapped around the existing eye and eyewall in Typhoon Maria and the structure exhibited concentric eyewalls.  The inner eyewall started to weaken as more air converged and rose in the much larger outer eyewall.  The wind speeds decreased slowly as the inner eyewall weakened.  The concentric eyewalls altered the structure of Typhoon Maria and the size of the circulation increased.  Winds to typhoon force extended out about 70 miles (110 km) from the center of circulation.  Winds to tropical storm force extended out about 235 miles (380 km) from the center.

Typhoon Maria was moving around the southern side of a subtropical ridge over the Western North Pacific Ocean.  The ridge was steering Maria toward the west-northwest and a general motion in that direction is expected to continue for another 12 to 24 hours.  On its anticipated track the center of Typhoon Maria will pass north of Taiwan, but Maria will continue to drop heavy rain over Taiwan.  Maria will make landfall on the east coast of China near Fuding during the next 6 to 12 hours.  The typhoon will bring gusty winds, a storm surge and heavy rain to Zhejiang province in eastern China.  The heavy rain could cause flash floods.

Typhoon Maria Nears Southern Ryukyu Islands

Typhoon Maria neared the southern Ryukyu Islands on Monday night.  At 11:00 p.m. EDT on Monday night the center of Typhoon Maria was located at latitude 24.3°N and longitude 126.4°E which put it about 130 miles (210 km) east of Ishigaki, Japan.  Maria was moving toward the west-northwest at 18 m.p.h. (29 km/h).  The maximum sustained wind speed was 125 m.p.h. (205 km/h) and there were wind gusts to 155 m.p.h. (250 km/h).  The minimum surface pressure was 949 mb.

Typhoon Maria weakened slowly on Monday, but it remained a powerful typhoon.  Maria moved over some slightly cooler water mixed to the surface by recent Typhoon Prapiroon when it passed near the Ryukyu Islands.  Maria was unable to extract enough energy from the upper ocean to maintain the intense wind speeds it produced during the weekend.  However, Typhoon Maria was still the equivalent of a major hurricane.  There was a circular eye with a diameter of 35 miles (55 km).  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Several bands of thunderstorms were revolving around the core of Typhoon Maria.   Storms in the core were generating strong upper level divergence which was pumping mass away from the center of circulation.

Winds to typhoon force extended out about 70 miles (110 km) from the center of circulation.  Winds to tropical storm force extended out about 200 miles from the center.  The Hurricane Intensity Index (HII) for Typhoon Maria was 23.6.  The Hurricane Size Index (HSI) was 23.8 and the Hurricane Wind Intensity Size Index (HWISI) was 47.4.  Those indices indicated that Typhoon Maria was capable of causing widespread major damage.

Typhoon Maria will move through an environment capable of sustaining a strong typhoon on Tuesday.  Maria will move west of the cooler water mixed to the surface by previous Typhoon Prapiroon and it will move over water where the Sea Surface Temperature is near 29°C.  Typhoon Maria will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Maria could weaken slowly on Tuesday if it is unable to extract enough energy from the upper ocean to sustain its circulation.  It could strengthen a little when it moves over slightly warmer water if it has time to extract more energy from the ocean.

Typhoon Maria was moving south of a subtropical ridge over the Western North Pacific Ocean.  The ridge was steering Maria toward the west-northwest and that general motion is expected to continue during the 36 hours.  On its anticipated track Typhoon Maria will reach the southern Ryukyu Islands in six to twelve hours.  Maria will bring destructive winds, heavy rain and a storm surge.  It will be capable of causing major damage to Miyako Jima, Ishigaki Jima, Iriomote Jima and the other islands in the southern Ryukyus.  The strongest part of Typhoon Maria will pass south of Okinawa, which could experience rainbands in the outer portion of the circulation.  Typhoon Maria will pass near northern Taiwan in about 18 hours.  It will bring strong winds and locally heavy rain to that area and flash floods could occur.  Maria could be near Fuding on the coast of China in about 24 hours.

Dangerous Typhoon Maria Churns Toward the Ryukyu Islands

Dangerous Typhoon Maria churned closer to the Ryukyu Islands on Sunday.  At 11:00 p.m. EDT on Sunday the center of Typhoon Maria was located at latitude 22.1°N and longitude 132.7°E which put it about 485 miles (780 km) southeast of Okinawa.  Maria was moving toward the west-northwest at 19 m.p.h. (31 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 922 mb.

Typhoon Maria has a large symmetrical circulation.  There is a circular eye with a diameter of 32 miles (52 km) at the center of Maria.  The eye is surrounded by a ring of strong thunderstorms and the strongest winds are occurring in that ring of storms.  Multiple bands of showers and thunderstorms are revolving around the core of Typhoon Maria.  Storms around the core are generating well developed upper level divergence which is pumping away large amounts of mass from the typhoon.

Winds to typhoon force extend out about 70 miles (110 km) from the center of circulation.  Winds to tropical storm force extend out about 230 miles (370 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Maria is 33.3.  The Hurricane Size Index (HSI) is 23.7 and the Hurricane Wind Intensity Size Index (HWISI) is 57.0.

Typhoon Maria will remain in an environment favorable for strong typhoons for another 24 to 36 hours.  Maria will move over water where the Sea Surface Temperature is near 29°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Typhoon Maria will remain a large and dangerous typhoon for another day or two.

Typhoon Maria was moving south of a subtropical ridge over the Western North Pacific Ocean.  The ridge was steering Maria toward the west-northwest and a general motion toward the west-northwest is likely to continue for another day or two.  On its anticipated track Typhoon Maria will approach the southern Ryukyu Islands in about 24 hours.  Maria could be near northern Taiwan in about 36 hours and it could approach the coast of China in about 48 hours.

Typhoon Maria will bring strong winds, locally heavy rain and a significant storm surge.  Maria will be capable of causing major damage over a widespread area.

Powerful Typhoon Maria Spins East of Taiwan

Powerful Typhoon Maria spun east of Taiwan on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon Maria was located at latitude 19.4°N and longitude 138.3°E which put it about 950 miles (1530 km) east-southeast of Okinawa.  Maria was moving toward the northwest at 13 m.p.h. (10 km/h).  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 185 m.p.h. (295 km/h).  The minimum surface pressure was 925 mb.

Typhoon Maria appeared to complete an eyewall replacement cycle on Saturday.  The completion of the cycle resulted in a  larger circulation.   There was an eye which had a diameter of 24 miles (38 km).  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of the circulation.  The rainbands northwest in the northwestern quadrant of Typhoon Maria were a little weaker than the bands in the other parts of the circulation.  Storms in the core of Maria were generating upper level divergence which was pumping mass away to the northeast of the typhoon.

Winds to typhoon force extended out about 70 miles (110 km/h) from the center of circulation.  Winds to tropical storm force extended out about 200 miles (320 km) from the center.  The Hurricane Intensity Index (HII) for Maria was 37.9.  The Hurricane Size Index (HSI) was 24.5 and the Hurricane Wind Intensity Size Index (HWISI) was 62.4.

Typhoon Maria will move through an environment mostly favorable for powerful typhoons on Sunday.   Maria will move over water where the Sea Surface Temperature is near 30°C.  It will move through an environment where the upper level winds are weak and there will be little vertical wind shear.  There appears to be some sinking motion and drier air northwest of Maria and that may be the reason why the rainbands were weaker in that part of the typhoon.  The drier air could inhibit further strengthening.  Typhoon Maria is likely to remain strong for another 24 to 48 hours.

Typhoon Maria was moving around the southern portion of a subtropical ridge over the Western North Pacific.  The ridge was steering Maria toward the northwest.  The ridge is forecast to strengthen and it will steer Typhoon Maria more toward the west-northwest.  On its anticipated track Typhoon Maria could approach the southern Ryukyu Islands in about 48 hours.  Maria could be near the northern end of Taiwan in about 60 hours.

Typhoon Maria Rapidly Intensifies to Equivalent of Cat. 5 Hurricane

Typhoon Maria rapidly intensified into the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale on Thursday night.  At 11:00 p.m. EDT on Thursday the center of Typhoon Maria was located at latitude 16.2°N and longitude 141.9°E which put it about 250 miles (405 km) northwest of Guam.  Maria was moving toward the northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 195 m.p.h. (315 km/h).  The minimum surface pressure was 918 mb.

Typhoon Maria continued to intensify rapidly on Thursday night and it reached the equivalent of Category 5 on the Saffir-Simpson Scale.  Maria is a strong, well organized typhoon.  There is a small circular eye at the center of circulation.  The eye is surrounded by a ring of strong thunderstorms and the strongest winds were occurring that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Typhoon Maria.  Storms in the core were generating strong upper level divergence which was pumping large amounts of mass away from the typhoon.  The rapid removal of mass allowed the surface pressure to decrease quickly and the wind speeds to increase rapidly.

Winds to typhoon/hurricane force extended out about 45 miles (75 km) from the center of circulation.  Winds to tropical storm force extended out about 155 miles (250 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Maria was 43.5.  The Hurricane Size Index (HSI) was 17.8 and the Hurricane Wind  Intensity Size Index (HWISI) was 51.3.

Typhoon Maria will move through an environment favorable for strong tropical cyclones for another day or two.  Maria will move over water where the Sea Surface Temperature is near 30°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Typhoon Maria could intensify further on Friday.  However, a rainband could wrap around the existing eye and eyewall.  If that occurs, then an eyewall replacement cycle will begin.  Maria would weaken while the inner eyewall dissipates.  The typhoon could strengthen again if the outer eyewall contracts around the center of circulation.

Typhoon Maria was moving south of a subtropical ridge which was steering Maria toward the northwest.  The northwesterly motion is expected to continue for another 24 to 48 hours.  After that time the ridge is forecast to strengthen and steer Maria more toward the west-northwest.  on its anticipated track Typhoon Maria could approach Okinawa and the Ryukyu Islands in about four days.  Maris is likely to be a powerful typhoon at that time.

Typhoon Maria Rapidly Intensifies Into Equivalent of Major Hurricane

Typhoon Maria rapidly intensified Thursday into the equivalent of a major hurricane as it moved west of the Mariana Islands.  At 5:00 p.m. EDT on Thursday the center of Typhoon Maria was located at latitude 15.7°N and longitude 142.1°E which put it about 210 miles (340 km) northwest of Guam.  Maria was moving toward the northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 125 m.p.h. (205 km/h) and there were wind gusts to 155 m.p.h. (250 km/h).  The minimum surface pressure was 950 mb.

After striking Guam as a tropical storm on Wednesday Maria rapidly intensified into a strong typhoon on Thursday.  A circular eye was evident on satellite imagery.  The eye was surrounded by a ring of strong thunderstorms.  Several bands of showers and thunderstorms were revolving around the core of the circulation.  Storm in the core were generating strong upper level divergence which was pumping mass away from the typhoon in all directions.  Winds to typhoon force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out about 155 miles (250 km) from the center.

The Hurricane Intensity Index (HII) for Typhoon Maria was 23.6.  The Hurricane Size Index (HSI) was 14.1 and the Hurricane Wind Intensity Size Index (HWISI) was 37.7.

Typhoon Maria will continue to move through an environment favorable for intensification for another day or two.  Maria will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region of weaker winds between an upper level low to the west and an upper level low to the east.  There will be little vertical wind shear.  Typhoon Maria is likely to intensify more on Friday and it could become the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale.  An eyewall replacement cycle could occur if one of the rainbands wraps around existing eye and eyewall.  If an eyewall replacement cycle starts, it will cause Typhoon Maria to weaken at least temporarily.

Typhoon Maria was moving south of a subtropical ridge over the Western North Pacific Ocean.  The ridge was steering Maria toward the northwest.  A general motion toward the northwest is expected to continue for another day or two.  The ridge is forecast to strengthen after that time and it will steer Typhoon Maria more toward the west-northwest.  On its anticipated track Maria will pass south of Iwo To.  Typhoon Maria could approach Okinawa and the Ryukyu Islands in four or five days.

Strengthening Tropical Storm Maria Brings Wind and Rain to Guam

Tropical Storm Maria strengthened quickly on Wednesday and it brought gusty winds and heavy rain to Guam.  The weather station at Andersen Air Force Base on Guam reported sustained winds to 44 m.p.h. (71 km/h) and wind gusts to 72 m.p.h. (116 km/h).  At 5:00 p.m. EDT on Wednesday the center of Tropical Storm Maria was located at latitude 13.9°N and longitude 144.7°E which put it about 5 miles (10 km/h) south of Andersen Air Force Base.  Maria was moving toward the north-northwest at 11 m.p.h. (17 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 987 mb.  Tropical Storm Warnings remained in effect for Guam and Rota.  Tropical Storm Watches were in effect for Saipan and Tinian.

The circulation of Tropical Storm Maria organized quickly on Wednesday.  A tight center of circulation contracted at the center of Maria.  A partial ring of thunderstorms formed on the east side of the center.  Numerous bands of showers and thunderstorms were revolving around the core of the circulation.  Storms around the core generated well developed upper level divergence which pumped mass away in all directions from the tropical storm.  Winds to tropical storm force extended out about 95 miles (155 km) from the center of circulation.

Tropical Storm Maria will move through an environment very favorable for intensification.  Maria will move over water where the Sea Surface Temperature is near 30°C.  Tropical Storm Maria will move under the western portion of an upper level ridge where the upper level winds are weak.  There will little vertical wind shear.  Upper level lows east and west of the ridge will enhance the upper level divergence.  Tropical Storm Maria will strengthen into a typhoon on Thursday.  Maria could intensify rapidly and it is likely to become the equivalent of a major hurricane.

Tropical Storm Maria was moving around the western end of a subtropical ridge which was steering Maria toward the north-northwest.  The ridge is forecast to steer Maria toward the northwest during the next few days.  On its anticipated track Tropical Storm Maria will move away from the Marianas and toward the Ryukyu Islands.  Tropical Storm Maria will continue to cause gusty winds and drop locally heavy rain on the southern Marianas for a few more hours.  Conditions will improve on Thursday when Maria moves away the Marianas.

Tropical Storm Maria Prompts Warning for Guam

Tropical Depression 10W strengthened into Tropical Storm Maria on Wednesday and a Tropical Storm Warning was issued for Guam.  At 5:00 a.m. EDT on Wednesday the center of Tropical Storm Maria was located at latitude 12.7°N and longitude 145.9°E which put it about 95 miles (155 km) southeast of Guam.  Maria was moving toward the north-northwest at 8 m.p.h. (13 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 1000 mb.  Tropical Storm Warnings were in effect for Guam and Rota.  Tropical Storm Watches were in effect for Saipan and Tinian.

The center of circulation in former Tropical Depression 10W became more well organized on Wednesday and the Japan Meteorological Agency designated the system as Tropical Storm Maria.  The circulation was still increasing in organization.  There was a distinct low level center of circulation.  Numerous bands of showers and thunderstorms were revolving around the center of circulation.  Storms near the center were generating upper level divergence which was pumping mass away from the tropical storm.

Tropical Storm Maria will move through an environment very favorable for intensification during the next few days.  Maria will move over water where the Sea Surface Temperature is near 30°C.  Tropical Storm Maria will move under the western end of an upper level ridge that is between two upper level lows which are east and west of the ridge.  The upper level winds will be relatively weak and there will be little vertical wind shear.  The combination of the ridge and two upper level lows will increase the upper level divergence.  Tropical Storm Maria will continue to strengthen.  Maria will become a typhoon later this week.  It could intensify rapidly once an eye forms and the inner core is well developed.

Tropical Storm Maria is moving around the western end of a subtropical ridge which is steering Maria toward the north-northwest.  On its anticipated track the center of Tropical Storm Maria will move near Guam and Rota later today.  A general motion toward the northwest is forecast for the next several days.  Maria could move in the direction of the Ryukyu Islands at the end of the week.

Tropical Storm Maria will bring gusty winds and heavy rain to the southern Mariana Islands.  The strongest winds and heaviest rain will affect Guam and Rota.  Gusty winds and heavy rain will also affect Saipan and Tinian.  Heavy rain could produce flash floods.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Prapiroon was moving over the Sea of Japan.  Prapiroon was bringing wind and rain to the northern Islands of Japan including Hokkaido and Honshu.  At 5:00 a.m. EDT on Wednesday the center of Tropical Storm Prapiroon was located at latitude 39.6°N and longitude 135.6°E which put it about 360 miles (585 km) west-southwest of Misawa, Japan.  Prapiroon was moving toward the northeast at 25 m.p.h. (40 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were winds gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 987 mb.

Typhoon Prapiroon Brings Wind and Rain to Kyushu

Typhoon Prapiroon brought wind and rain to Kyushu on Monday night.  At 11:00 p.m. EDT on Monday the center of Typhoon Prapiroon was located at latitude 32.8°N and longitude 128.6°E which put it about 110 miles (180 km) southwest of Sasebo, Japan.  Prapiroon was moving toward the north-northeast at 17 m.p.h. (27 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 968 mb.

Rainbands on the eastern side of Typhoon Prapiroon were moving over parts of Kyushu.  Those bands were causing gusty winds and they were dropping locally heavy rain.  The circulation of Typhoon Prapiroon was exhibiting the effects of a more midlatitude environment.  Drier air was wrapping around the western and southern portions of the typhoon.  The bands in those parts of Prapiroon consisted primarily of showers and low clouds.  The western portion of the eyewall was also weakening.  There were still strong thunderstorms in the eastern half of the eyewall and that was where the strongest winds were occurring.  Several bands of showers and thunderstorms on the eastern side of the circulation were revolving around the core of Typhoon Prapiroon.

Typhoon Prapiroon will be moving through an environment that will cause it to weaken.  Prapiroon was moving over water where the Sea Surface Temperature was near 26°C.  However, it will move over water where the Sea Surface Temperature is near 24°C when it moves north of Japan.  An upper level trough west of South Korea will produce southwesterly winds which will cause vertical wind shear.  The combination of cooler water and more vertical wind shear will cause Typhoon Prapiroon to weaken to a tropical storm on Tuesday.  Prapiroon could begin a transition to an extratropical cyclone because of the effects of the midlatitude environment.

Typhoon Prapiroon was being steered toward the north-northeast by the upper level trough.  Stronger westerly winds will steer Prapiroon more toward the northeast when it gets north of Japan.  On its anticipated track the center of Typhoon Prapiroon will pass near the northwestern portion of Kyushu.  The center of Prapiroon is forecast to pass between south Korean and Japan and then to move over the Sea of Japan.  Rainbands on the eastern side of Typhoon Prapiroon will cause gusty winds and drop heavy rain over parts of Kyushu.  Heavy could cause flash floods in some locations.  Prapiroon could also bring wind and rain to southeastern South Korea and parts of northern Honshu.

Elsewhere over the Western North Pacific Ocean Tropical Depression 10W formed southeast of Guam.  At 11:00 p.m. EDT on Monday the center of Tropical Depression 10W was located at latitude 10.6°N and longitude 145.7°E which put it about 205 miles (330 km) south-southeast of Guam.  It was moving toward the north-northwest at 6 m.p.h. (10 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 1003 mb.  A Tropical Storm Warning was issued for Guam.  A Tropical Storm Watch was issued for Tinian and Saipan.