Typhoon Halong Strengthens to Equivalent of a Major Hurricane

Typhoon Halong strengthened to the equivalent of a major hurricane northeast of the Northern Marianas on Monday.  At 4:00 p.m. EST on Monday the center of Typhoon Halong was located at latitude 18.9°N and longitude 152.1°E which put it about 390 miles (630 km) south of Minami Tori Shima, Japan.  Halong was moving toward the northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 952 mb.

Typhoon Halong continued to strengthen on Monday and it reached the equivalent of a major hurricane.  A small, well formed circular eye was evident on infrared satellite images.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Typhoon Halong.  Storms near the core were generating strong upper level divergence which was pumping mass away from the typhoon.

The circulation around Typhoon Halong increased in size on Monday.  Winds to typhoon force extended out 45 miles (75 km) from the center of circulation.  Winds to tropical storm force extended out 160 miles (260 km) from the center.  The Hurricane intensity Index (HII) for Typhoon Halong was 22.0.  The Hurricane Size Index (HSI) was 14.3 and the Hurricane Wind Intensity Size Index was 36.3.  Halong was capable of causing major damage.

Typhoon Halong will remain in an environment favorable for intensification for another 24 hours.  Halong will move over water where the Sea Surface Temperature is near 29°C.  It will move under the northwestern portion of an upper level ridge where the winds are weaker and there will be little vertical wind shear.  An upper level trough southwest of Japan will approach Typhoon Halong in 24 hours.  The trough will produce stronger southwesterly winds which will cause more vertical wind shear.  Halong will start to weaken when the wind shear increases.

Typhoon Halong will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean during the next 36 to 48 hours.  The ridge will steer Halong toward the north-northwest.  Halong will move toward the northeast later this week after if moves around the western end of the high pressure system.  On its anticipated track Typhoon Halong could approach Minami Tori Shima in less than 72 hours.

Tropical Cyclone Maha Strengthens into Equivalent of a Major Hurricane

Tropical Cyclone Maha strengthened into the equivalent of a major hurricane on Sunday night.  At 10:00 p.m. EST on Sunday the center of Tropical Cyclone Maha was located at latitude 18.2°N and longitude 64.8°E which put it about 525 miles (845 km) west of Mumbai, India.  Maha was moving toward the northwest at 4 m.p.h. (6 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 958 mb.

Tropical Cyclone Maha continued to intensify on Sunday and it became the equivalent of a major hurricane.  There was a small eye at the center of circulation.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Maha.  The strongest rainbands were in the eastern half of the tropical cyclone.  Bands in the western half of Maha consisted primarily of showers and lower clouds.  Storms near the core of the circulation were generating upper level divergence which was pumping mass away from the tropical cyclone.

The circulation around Tropical Cyclone Maha was relatively small.  Winds to hurricane/typhoon force extended out 20 miles (35 km) from the center of circulation.  Winds to tropical storm force extended out 75 miles (120 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Maha was 20.6.  The Hurricane Size Index (HSI) was 6.6 and the Hurricane Wind Intensity Size Index (HWISI) was 27.2.  Maha was capable of causing localized major damage.

Tropical Cyclone Maha will move through an environment favorable for intensification for another 12 to 18 hours.  Maha will move over water where the Sea Surface Temperature is near 28°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Maha may be pulling drier air into the western half of the circulation, which could be the reason for the lack of thunderstorms in that half of the circulation.  The drier air could prevent significant additional intensification if it gets pulled into the core of the circulation.  An upper level trough will approach Maha from the west in about 18 hours.  The trough will produce stronger westerly winds which will cause the vertical wind shear to increase.  Tropical Cyclone Maha will begin to weaken when the wind shear increases.

Tropical Cyclone Maha will move around the western end of a ridge of high pressure over India and the eastern Arabian Sea during the next 24 hours.  The ridge will steer Maha slowly toward the northwest.  When the upper level trough approaches Tropical Cyclone Maha, the westerly winds will steer the tropical cyclone back toward the east.  On its anticipated track Maha could approach the coast of India north of Mumbai in about 72 hours.

Halong Strengthens into a Typhoon East of the Northern Marianas

Former Tropical Storm Halong strengthened into a typhoon east of the Northern Marianas on Sunday.  At 4:00 p.m. EDT on Sunday the center of Typhoon Halong was located at latitude 17.0°N and longitude 153.3°E which put it about 520 miles (840 km) east-northeast of Saipan.  Halong was moving toward the northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 979 mb.

The circulation around former Tropical Storm Halong exhibited much better organization on Sunday.  An eye with a diameter of approximately 12 miles (19 km) formed at the center of Halong.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Typhoon Halong.  The strongest rainbands were north and east of the center of circulation.  Bands in the western half of Halong consisted primarily of showers and lower clouds.  Typhoon Halong may have been pulling sinking, drier air into the western half of the circulation, which may be why the bands were weaker in that part of the typhoon.  Storms around the core of Halong were generating strong upper level divergence which was pumping mass away from the typhoon.  Winds to typhoon force extended out 10 miles (15 km) from the center of circulation.  Winds to tropical storm force extended out 175 miles (280 km) from the center.

Typhoon Halong will move through an environment favorable for intensification during the next 36 to 48 hours.  Halong will move over water where the Sea Surface Temperature is near 29°C.  It will move under the western part of an upper level ridge where the winds are weak.  So, there will not be a lot of vertical wind shear.  Typhoon Halong will continue to intensify and it could strengthen into the equivalent of a major hurricane.

Typhoon Halong will move around the western end of a ridge of high pressure over the Western North Pacific Ocean.  The ridge will steer Halong toward the northwest during the next 24 hours.  After that time Typhoon Halong will move more toward the north while it moves around the western end of the ridge.  Halong will move northeastward after it moves around the end of the ridge.  On its anticipated track Typhoon Halong is forecast to remain northeast of the Northern Marianas.  Halong is expected to pass between Iwo To and Wake Island later next week.

Tropical Cyclone Maha Strengthens to Equivalent of a Hurricane/Typhoon

Tropical Cyclone Maha strengthened into the equivalent of a hurricane/typhoon over the Arabian Sea west of India on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Cyclone Maha was located at latitude 17.7°N and longitude 66.1°E which put it about 440 miles (705 km) west-southwest of Mumbai, India.  Maha was moving toward the west-northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 997 mb.

The circulation around Tropical Cyclone Maha exhibited better organization on Saturday.  An eye formed at the center of Maha.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in the ring of storms.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Maha.  The strongest rainbands were in the southern half of the circulation.  Storms near the core were generating upper level divergence which was pumping mass away from the tropical cyclone.  Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out 65 miles (105 km) from the center.

Tropical Cyclone Maha will move through an environment favorable for intensification during the next 36 to 48 hours.  Maha will move over water where the Sea Surface Temperature is near 28°C.  It will move under the western portion of an upper level ridge where the winds are weak and there will be little vertical wind shear.  Tropical Cyclone Maha will continue to intensify and it could strengthen into the equivalent of a major hurricane during the n ext several days.

Tropical Cyclone Maha will move around the southwestern part of a ridge of high pressure over India and the eastern Arabian Sea.  The high will steer Maha toward the northwest during the next day or two.  An upper level trough will approach Tropical Cyclone Maha from the northwest in two or three days.  Westerly winds blowing around the southern end of the trough will turn Maha back toward the east.  On its anticipated track Tropical Cyclone Maha could approach the west coast of India north of Mumbai in about four days.

Tropical Storm Halong Develops East of the Marianas

Tropical Storm Halong developed east of the Marianas on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Halong was located at latitude 13.3°N and longitude 156.7°E which put it about 820 miles (1325 km) east of Guam.  Halong was moving toward the northwest at 9 m.p.h. (15 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.

A distinct low level center of circulation formed in an area of thunderstorms east of the Marianas on Saturday.  When more thunderstorms formed near the center of circulation, the Japan Meteorological Agency designated the system as Tropical Storm Halong.  The circulation around Halong appeared to be organizing quickly.  New thunderstorms were forming close to the center of circulation.  Bands of showers and thunderstorms were also organizing quickly and the bands were starting to revolve around the center of Tropical Storm Halong.  Storms near the center were generating upper level divergence which was pumping mass away from the tropical storm in all directions.  Winds to tropical storm force extended out 150 miles (240 km) from the center of circulation.

Tropical Storm Halong will move through an environment favorable for intensification during the next two to three days.  Halong will move over water where the Sea Surface Temperature is near 29°C.  It will move under the western end of an upper level ridge over the Western North Pacific Ocean.  The winds will be blowing from the south at all levels and so there will be little vertical wind shear.  Tropical Storm Halong will continue to intensify and it could strengthen rapidly.  Halong is likely to strengthen into a typhoon within 36 hours.

The ridge over the Western North Pacific will steer Tropical Storm Halong toward the northwest during the next several days.  On its anticipated track Halong will be northeast of the Marianas by the end of the weekend.

Tropical Cyclone Maha Reorganizes Southwest of Mumbai

Tropical Cyclone Maha reorganized over the Arabian Sea southwest of Mumbai, India on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Mumbai was located at latitude 16.2°N and longitude 68.8°E which put it about 320 miles (520 km) southwest of Mumbai, India.  Maha was moving toward the northwest at 7 m.p.h. (11 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.

After pulling drier air from India into the circulation and weakening on Thursday, Tropical Cyclone Maha appeared to be reorganizing on Friday afternoon.  Many of the thunderstorms in the rainbands weakened on Thursday.  A band of strong thunderstorms reformed on Friday and it was wrapping around the southern and eastern sides of the center of circulation.  The inner end of the rainband was wrapping closer to the center of the circulation and an inner core appeared to be reforming.  Storms in the band started to generate upper level divergence which was pumping mass away from the tropical cyclone.  Winds to tropical storm force extended out about 75 miles (120 km) from the center of circulation.

Tropical Cyclone Maha will move through an environment favorable for intensification during the next 24 to 48 hours.  Maha will move over water where the Sea Surface Temperature is near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Maha will intensify during the next day or two and it is likely to strengthen into the equivalent of a hurricane/typhoon.

Tropical Cyclone Maha will move south of a ridge of high pressure over South Asia.  The high will steer Maha toward the northwest during the next several days.  On its anticipated track Tropical Cyclone Maha will remain west of India during the weekend.

Elsewhere over the Arabian Sea,, Tropical Cyclone Kyarr meandered northeast of Somalia.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Kyarr was located at latitude 16.0°N and longitude 58.0°E whichput it about 355 miles (575 km) northeast of Socotra, Yemen.  Kyar was moving toward the southwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1002 mb.

Tropical Cyclone Maha Forms Southwest of India

Tropical Cyclone Maha formed over the Arabian Sea southwest of India on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Tropical Cyclone Maha was located at latitude 11.0°N and longitude 73.3°E which put it about 140 miles (225 km) southwest of Mangalore, India.  Maha was moving toward the northwest at 11 m.p.h. (17 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.

More thunderstorms formed near the center of a low pressure over the Arabian Sea west of the southern tip of India on Wednesday and the India Meteorological Department designated the system as Tropical Cyclone Maha.  The circulation around Tropical Cyclone Maha was still organizing on Wednesday.  Bands of showers and thunderstorms were forming and the bands were starting to revolve around the center of Maha.  The strongest thunderstorms were occurring in bands in the western half of the circulation.  Some thunderstorms were also forming in bands in the eastern half of the tropical cyclone, but the proximity to southern India may have been making the air a little drier in that part of Maha.  Winds to tropical storm force extended out about 80 miles (130 km) from the center of circulation.

Tropical Cyclone Maha will move through an environment favorable for intensification during the next few days.  Maha will move over water where the Sea Surface Temperature is near 29°C.  It will move underneath the axis of an upper level ridge running east to west over India and the eastern Arabian Sea.  The upper level winds will be weak and there will not be a lot of vertical wind shear during the next day or two.  Tropical Cyclone Maha will continue to intensify and it is forecast to strengthen into the equivalent of a hurricane/typhoon.  Maha could strengthen more quickly once an inner core with an eye and an eyewall develop.

The middle portion of the upper level ridge will steer Tropical Cyclone Maha toward the northwest during the next 48 hours.  When Maha reaches the northern Arabian Sea a second ridge of high pressure over South Asia will steer the tropical cyclone toward the west.  On its anticipated track Tropical Cyclone Maha will move parallel to the west coast of India.

Elsewhere over the Arabian Sea, Tropical Cyclone Kyarr was weakening rapidly southeast of Oman.  The circulation pulled drier air from the Arabian peninsula into the core of Kyarr and most of the thunderstorms dissipated when the drier air reached them.  At 5:00 p.m. EDT on Wednesday the center of Tropical Cyclone Kyarr was located at latitude 18.3°N and longitude 60.7°E which put it about 190 miles (305 km) southeast of Masirah Island, Oman.  Kyarr was moving toward the southwest at 6 m.p.h. (10 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 987 mb.

Tropical Storm Matmo Makes Landfall in Vietnam

Tropical Storm Matmo made landfall on the southern coast of Vietnam near Quy Nhon on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Tropical Storm Matmo was located at latitude 13.7°N and longitude 108.2°E which put it about 50 miles (80 km) west of Quy Nhon, Vietnam.  Matmo was moving toward the west at 13 m.p.h. (20 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 944 mb.

Tropical Storm Matmo organized quickly as it approached the coast of southern Vietnam on Wednesday.  The inner end of a band of showers and thunderstorms wrapped about 75% around the center of circulation and an eye appeared to be forming.  Thunderstorms near the center of Matmo were generating upper level divergence which was pumping mass away from the tropical storm.  The removal of mass allowed the pressure to decrease which caused the wind speed to increase.  The maximum sustained wind speed at the time when Tropical Storm Matmo made landfall was 60-65 m.p.h. (95-105 km/h).

Tropical Storm Matmo began to weaken after the center moved over land.  The strongest winds were occurring in bands of showers and thunderstorms in the eastern half of Matmo over the South China Sea.  Wind speeds in the parts of the circulation what were over land were less.  Tropical Storm Matmo will continue to move westward during the next several days.  Matmo will drop heavy rain over parts of southern Vietnam, Cambodia, southern Laos, and Thailand.  Heavy rain could cause floods in some locations.

Subtropical Storm Rebekah Forms West of the Azores

Subtropical Storm Rebekah formed west of the Azores on Wednesday afternoon.  At 5:00 p.m. EDY on Wednesday the center of Subtropical Storm Rebekah was located at latitude 38.3°N and longitude 40.7°W which put it about 745 miles (1195 km) west of the Azores.  Rebekah was moving toward the east at 13 m.p.h. (20 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 987 mb.

Subtropical Storm Rebekah formed in a manner very similar to the way Hurricane Pablo developed last week.  A small center of circulation developed in the middle of a much larger, extratropical cyclone.  Thunderstorms developed around the center of the small low pressure system.  Even though the small low was over water where the Sea Surface Temperature is near 22°C, cold air in the upper troposphere generated enough instability to allow the thunderstorms to grow upward.  Bands of showers and thunderstorms developed and began to revolve around the small low pressure system, and the National Hurricane Center designated the system at Subtropical Storm Rebekah.  Winds to tropical storm force extended out 90 miles (145 km) from the center of Rebekah.

Subtropical Storm Rebekah could strengthen during the next 24 hours.  Although Rebekah will move over water where the Sea Surface Temperature is near 22°C, colder air in the middle and upper troposphere will keep enough potential instability in the atmosphere to allow for the continued development of thunderstorms.  Since Rebekah is at the center of the larger low pressure system, the vertical wind shear will be less.  Subtropical storm Rebekah may intensify during the next day or so and it could make a transition to a tropical storm.

Subtropical Storm Rebekah will move eastward along with the larger low pressure system that surrounds the much smaller subtropical storm.  Southerly winds blowing around the eastern side of the larger low could push Rebekah toward the north at times.  On its anticipated track Subtropical Storm Rebekah could approach the western Azores on Friday.

Tropical Cyclone Kyarr Weakens East of Oman

Tropical Cyclone Kyarr weakened east of Oman on Tuesday.  At 11:00 EDT on Tuesday the center of Tropical Cyclone Kyarr was located at latitude 19.5°N and longitude 62.0°E which put it about 220 miles (355 km) east-southeast of Masirah Island, Oman.  Kyarr was moving toward the west at 6 m.p.h. (10 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 954 mb.

The structure of the circulation around Tropical Cyclone Kyarr exhibited less organization on Tuesday.  The southwestern part of the ring of thunderstorms around the eye weakened.  In addition, bands of showers and thunderstorms in the western half of Kyarr also weakened.  Two factors seemed to be contributing to the weakening trend.  Tropical Cyclone Kyarr moved slowly during the last 24 to 36 hours.  The circulation mixed cooler water to the upper levels of the Arabian Sea and Kyarr was not able to extract as much energy from the water.  The circulation around Tropical Cyclone Kyarr may have pulled drier air from the Arabian peninsula into the western half of the circulation.  Even though Kyarr weakened on Tuesday. winds to hurricane/typhoon force extended out 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out 130 miles (210 km) from the center.

Tropical Cyclone Kyarr will probably continue to weaken during the next several days.  Kyarr will move away from the cooler water it mixed to the surface and it will be in an area where there will not be a lot of vertical wind shear.  However, Tropical Cyclone Kyarr is likely to draw more drier air into the circulation.  The drier air will make it more difficult for thunderstorms to develop in rainbands around the tropical cyclone.

Tropical Cyclone Kyarr will move south of a ridge of high pressure over southwest Asia.  The high is forecast to strengthen during next several days.  When the high strengthens it will steer Kyarr toward the southwest.  On its anticipated track Tropical Cyclone Kyarr will move parallel to the coast of Oman.  Kyarr could approach Socotra Island and Somalia in four or five days.