Tag Archives: SH18

Tropical Cyclone Wasi Brings Wind and Rain to Samoa

Tropical Cyclone Wasi brought wind and rain to Samoa  on Saturday.  At 10:00 p.m. EST on Saturday the center of Tropical Cyclone Wasi was located at latitude 16.7°S and longitude 171.3°W which put it about 140 miles (225 km) south-southwest of Pago Pago, American Samoa.  Wasi was moving toward the south-southeast at 14 m.p.h. (22 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 996 mb.

The eastern side of Tropical Cyclone Wasi brought wind and rain to parts of Samoa on Saturday.  A weather station in Pago Pago, American Samoa reported a sustained wind speed of 25 m.p.h. (40 km/h) and a wind gust of 43 m.p.h. (69 km/h).  Several inches of rain also fell on parts of Samoa.

Tropical Cyclone Wasi moved under the western side of an upper level ridge over the South Pacific Ocean.  The ridge produce strong northerly winds which blew across the top of Wasi.  Those winds caused strong vertical wind shear and Tropical Cyclone Wasi began to weaken.  Many of the taller thunderstorms dissipated.  Some storms were still occurring in a band south and east of the center of circulation.  Bands in other parts of the circulation consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out 75 miles (120 km) from the center of Wasi.

Tropical Cyclone Wasi will move through an environment unfavorable for intensification.  Wasi will move over water where the Sea Surface Temperature is near 28°C.  However, the upper level ridge will continue to cause strong vertical wind shear.  The shear will be strong enough to prevent significant intensification and Tropical Cyclone Wasi could continue to weaken since it has a small circulation.

Tropical Cyclone Wasi will move around the western end of a high pressure system over the South Pacific Ocean.  The high will steer Wasi toward the south.  On its anticipated track Tropical Cyclone Wasi could pass near Niue in about 18 hours.  Wasi will bring gustier winds and rain showers to Niue on Sunday.

Elsewhere over the South Pacific Ocean, Tropical Cyclone Vicky was dissipating south of Niue.  At 10:00 p.m. EST on Saturday the center of Tropical Cyclone Vicky was located at latitude 22.6°S and longitude 168.6°W which put it about 250 miles (400 km) south-southeast of Niue.  Vicky was moving toward the south at 10 m.p.h. (16 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.

Tropical Cyclone Wasi Develops Near Samoa

Tropical Cyclone Wasi developed near Samoa on Friday night.  At 10:00 p.m. EST on Friday the center of Tropical Cyclone Wasi was located at latitude 13.6°S and longitude 172.9°W which put it about 20 miles (35 km) west of Falealupo, Samoa and about 185 miles (300 km) west-northwest of Pago Pago, American Samoa.  Wasi was moving toward the southeast 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 993 mb.

Tropical Cyclone Wasi spun up out of the same elongated trough of low pressure near Samoa that produced Tropical Cyclone Vicky on Thursday.  A small center of low pressure developed west-northwest of Samoa on Friday.  More thunderstorms formed near the center of circulation and the system was classified as Tropical Cyclone Wasi.  Microwave satellite imagery indicated that there was a tight inner core in the tropical cyclone.  Storms near the core were generating upper level divergence which was pumping mass away from Tropical Cyclone Wasi.  The circulation around Wasi was even smaller than the circulation around Tropical Cyclone Vicky.  Winds to tropical storm force only extended out about 50 miles (80 km) from the center of Tropical Cyclone Wasi.

Tropical Cyclone Wasi will move into an environment somewhat favorable for intensification during the next 24 to 36 hours.  Wasi will move over water where the Sea Surface Temperature is near 28°C.  It will move under the western end of an upper level ridge over the South Pacific Ocean.  The ridge will produce northwesterly winds which will blow toward the top of the tropical cyclone.  Those winds will cause moderate vertical wind shear, but the winds may not be strong enough to prevent intensification.  Tropical Cyclone Wasi could strengthen during the next 24 to 36 hours.  Since the circulation around Wasi is so small, if the tropical cyclone moves into an area where the upper level winds are stronger, it could weaken quickly.

Tropical Cyclone Wasi will move around the western end of a high pressure system over the South Pacific Ocean.  The high will steer Wasi toward the southeast during the next 12 hours.  Wasi will move more toward the south later in the weekend.  On its anticipated track Tropical Cyclone Wasi will bring gust winds and locally heavy rain to portions of Samoa during the next 24 hours.

Elsewhere over the South Pacific Ocean, Tropical Cyclone Vicky weakened as it passed near Niue on Friday.  At 10:00 p.m. EST on Friday the center of Tropical Cyclone Vicky was located at latitude 19.7°S and longitude 168.7°W which put oit about 95 miles (150 km) southeast of Niue.  Vicky was moving toward the south-southeast at 13 m.p.h. (20 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 1001 mb.

Tropical Cyclone Idai Drops Heavy Rain on Mozambique and Zimbabwe

Tropical Cyclone Idai dropped heavy rain on parts of Mozambique and Zimbabwe on Friday.  At 11:00 p.m. EDT on Friday the center of Tropical Cyclone Idai was located at latitude 19.0°S and longitude 32.5°E which put it about 50 miles (80 km) southwest of Mutare, Zimbabwe.  Idai was moving toward the west-northwest at 7 m.p.h. (11 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 985 mb.

Although the wind speeds around Tropical Cyclone Idai decreased steadily on Friday, the circulation remained very well organized.  An inner rainband wrapped most of the way around a well defined center of circulation.  Bands of showers and thunderstorms were revolving around the center of Idai.  The strongest bands were occurring in the southern half of the circulation.  Storms near the core of the circulation were still generating upper level divergence which was pumping mass away from the tropical cyclone.

Tropical Cyclone Idai dropped heavy rain from the coast of central Mozambique near Beira where Idai caused significant damage westward to the eastern Zimbabwe.  Persistent heavy rain was likely causing flooding along some of the rivers in central Mozambique and eastern Zimbabwe.  Tropical Cyclone Idai is forecast to continue to move toward the west-northwest and heavy rain is likely to spread over more of Zimbabwe.

Tropical Cyclone Idai Makes Landfall in Mozambique

Strong Tropical Cyclone Idai made landfall in Mozambique very close to Beira on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Idai was located at latitude 19.4°S and longitude 34.5°E which put it about 30 miles (50 km) northwest of Beira, Mozambique.  Idai was moving toward the west at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 125 m.p.h. (205 km/h).  The minimum surface pressure was 958 mb.

The core of Tropical Cyclone Idai moved directly over Beira, Mozambique.  The eye moved over Beira.  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (210 km/h) at the time of landfall.  Winds to hurricane/typhoon force extended out about 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out about 150 miles from the center of Tropical Cyclone Idai.

The Hurricane Intensity Index (HII) for Tropical Cyclone Idai was 19.2 at the time of landfall.  The Hurricane Size Index (HSI) was 13.8 and the Hurricane Wind Intensity Size Index (HWISI) was 33.0.  Tropical Cyclone Idai was capable of causing very serious wind damage.  Both sides of the eyewall which contained the strongest winds moved over Beira.  The relatively slow rate at which Idai was moving would have resulted in a prolonged period of strong winds, which would have increased the potential for damage.

Clockwise rotation around Tropical Cyclone Idai would have produced strong southerly winds when Idai approached Beira.  Those winds would have pushed water into the mouth of the Rio Pungoe which is on the western side of Beria.  There could have been an enhanced storm surge of 12 to 18 feet (4 to 6 meters) in that area.  Beira is one of the largest cities in Mozambique and it has a population of over half a million people.  Idai could have cause very serious damage around Beira.

Tropical Cyclone Idai will move toward the west-northwest during the next day or two.  On its anticipated track Idai will move farther inland over Mozambique and it will eventually move over Zimbabwe.  Tropical Cyclone Idai will weaken steadily as it moves inland, but it will drop heavy rain over central Mozambique and over parts of Zimbabwe.  The heavy rain could cause flooding along portions of Rio Pungoe and Rio Buzi as well as other parts of central Mozambique and Zimbabwe.

Major Tropical Cyclone Idai Nears Mozambique

Major Tropical Cyclone Idai neared the coast of Mozambique on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone Idai was located at latitude 19.7°S and longitude 37.5°E which put it about 170 miles (275 km) east of Beira, Mozambique.  Idai was moving toward the west-southwest 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 949 mb.

Tropical Cyclone Idai strengthened back into the equivalent of a major hurricane after it completed an eyewall replacement cycle on Wednesday.  An eye with a diameter of 35 miles (55 km) appeared on satellite images after the remnants of the original inner eyewall weakened.  A ring of strong thunderstorms surrounded the large eye and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Idai.  Storms near the core of Idai were generating strong upper level divergence which was pumping mass away from the tropical cyclone.

The size of the circulation around Tropical Cyclone Idai increased during the eyewall replacement cycle.  Winds to hurricane/typhoon 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 Tropical Cyclone Idai was 22.1.  The Hurricane Size Index (HSI) was 16.5 and the Hurricane Wind Intensity Size Index (HWISI) was 38.6.

Tropical Cyclone Idai will remain in an environment favorable for intensification until it reaches the coast of Mozambique.  Idai 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.  Idai could strengthen before it reaches the coast.

Tropical Cyclone Idai will move north of a subtropical ridge over southern Africa.  The ridge will steer Idai toward the west.  On its anticipated track Tropical Cyclone Idai will make landfall on the coast of Mozambique near Beira in less than 24 hours.  Idai will bring very strong winds and it will be capable of causing regional major damage.  Tropical Cyclone Idai will also drop heavy rain over parts of Mozambique and it will likely cause flooding in some locations.

Tropical Cyclone Idai Strengthens to Equivalent of a Major Hurricane

Tropical Cyclone Idai strengthened into the equivalent of a major hurricane over the Mozambique Channel on Monday.  At 11:00 p.m. EDT on Monday the center of Tropical Cyclone Idai was located at latitude 18.2°S and longitude 42.0°E which put it about 490 miles (785 km) east-northeast of Beira, Mozambique.  Idai was moving toward the southwest at 5 m.p.h. (8 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 952 mb.

Tropical Cyclone Idai intensified into the equivalent of a major hurricane on Monday and then it appeared to begin an eyewall replacement cycle.  A rainband wrapped around the original eye and eyewall.  Convergence became concentrated on the outer eyewall and the inner eyewall began to dissipate.  The overall size of the circulation increased.  Winds to hurricane/typhoon force extended out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out about 130 miles (210 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Idai was 20.6.  The Hurricane Size Index (HSI) was 15.2 and the Hurricane Wind Intensity Size Index (HWISI) was 35.8.

Tropical Cyclone Idai will remain in an environment favorable for intensification for several more days.  Idai will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Idai could strengthen further once the inner eyewall dissipates completely and the eyewall replacement cycle ends.

Tropical Cyclone Idai will move around the southeastern part of a subtropical ridge over southern Africa.  The ridge will steer Idai on a course that is a little south of due west.  On its anticipated track Tropical Cyclone Idai could reach the coast of Mozambique near Beira in less than 72 hours.  Idai could still be the equivalent of a major hurricane when it reaches the coast.

Tropical Cyclone Idai Rapidly Intensifies Into Equivalent of Hurricane/Typhoon

Tropical Cyclone Idai rapidly intensified into the equivalent of a hurricane/typhoon over the Mozambique Channel on Sunday.  At 11:00 p.m. EDT on Sunday the center of Tropical Cyclone Idai was located at latitude 17.4°S and longitude 43.2°E which put it about 75 miles (120 km) northwest of Maintirano, Madagascar.  Idai was moving toward the south at 1 m.p.h. (2 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 125 m.p.h. (205 km/h).  The minimum surface pressure was 958 mb.

Tropical Cyclone Idai intensified rapidly on Sunday.  An eye was apparent on satellite imagery,  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 Idai.  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 about 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out about 100 miles (160 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Idai was 17.8.  The Hurricane Size Index (HSI) was 10.7 and the Hurricane Wind Intensity Size Index (HWISI) was 28.5.

Tropical Cyclone Idai will continue to move through an environment favorable for intensification during the next day or two,  Idai will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Idai could intensify into the equivalent of a major hurricane during the next 24 hours.

Tropical Cyclone Idai will move around the eastern end of a subtropical ridge over southern Africa. The ridge will steer Idai toward the west during the next several days.  On its anticipated track Tropical Idai could approach the coast of Mozambique in about four days.  Idai could be the equivalent of a major hurricane at that time.

Tropical Cyclone Idai Forms Over Mozambique Channel

Tropical Cyclone Idai formed over the Mozambique Channel on Saturday.  At 10:00 p.m. EST on Saturday the center of Tropical Cyclone Idai was located at latitude 17.2°S and longitude 42.5°E which put it about 135 miles (220 km) west-northwest of Maintirano, Madagascar.  Idai was moving toward the southeast at 6 m.p.h. (10 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 994 mb.

The circulation around Tropical Cyclone Idai organized quickly on Saturday.  The inner portion of a rainband wrapped around the eastern and southern sides of the center of circulation.   Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Idai.  Storms near the core began to generate upper level divergence which pumped mass away from the tropical cyclone.  Winds to tropical storm force extended out about 100 miles (160 km) from the center of circulation.

Tropical Cyclone Idai will move through an environment favorable for intensification during the next several days.  Idai will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Idai will continue to intensify and it could strengthen into the equivalent of a hurricane/typhoon within 36 hours.  Once the inner core is fully organized, Idai could strengthen rapidly and it could intensify into the equivalent of a major hurricane.

Tropical Cyclone Idai will move around the eastern end of a subtropical ridge over southern Africa.  The ridge will steer Idai back toward the west.  On its anticipated track Tropical Cyclone Idai could approach the coast of Mozambique in about four days.  Idai could be the equivalent of a major hurricane by that time.

Tropical Cyclone Iris Redevelops East of Queensland.

Tropical Cyclone Iris redeveloped east of Queensland on Sunday night.  At 11:00 p.m. EDT on Sunday the center of Tropical Cyclone Iris was located at latitude 16.9°S and longitude 148.7°E which put it about 190 miles (310 km) east of Cairns, Australia.  Iris was moving toward the 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 995 mb.

Tropical Cyclone Iris formed over the Coral Sea last week but wind strong vertical shear quickly weakened Iris into an area of low pressure.  The low pressure system meandered over the Coral Sea east of Australia during the past few days.  More thunderstorms developed near the center of circulation on Sunday and the Australian Bureau of Meteorology designated the system as Tropical Cyclone Iris again.

The circulation around Tropical Cyclone Iris was still reorganizing on Sunday night.  A distinct low level center of circulation was evident on visible satellite images.  More thunderstorms were developing near the center.  A primary rainband wrapped around the northern, eastern and southern sides of the center of circulation.  Bands northwest of the center consisted mainly of showers and low clouds.  Storms near the core of the circulation generated upper level divergence which was pumping mass away to the east of the tropical cyclone.

Tropical Cyclone Iris will move through an environment somewhat favorable for intensification on Monday.  Iris will move over water where the Sea Surface Temperature is 29°C.  It is moving around the western end of an upper level ridge.  The ridge is producing northwesterly winds which were blowing toward the top of the circulation.  Those winds were causing moderate vertical wind shear and they may have been the reason for the lack of strong rainbands northwest of the center of circulation.  The wind shear is likely to inhibit intensification, but it probably won’t prevent Tropical Cyclone Iris from intensifying on Monday.

Tropical Cyclone Iris was moving around the western end of a subtropical ridge which was steering Iris toward the southwest.  Iris will likely move more toward the south and then southeast as it rounds the western end of the ridge.  On its anticipated track Tropical Cyclone Iris is expected to remain east of Queensland.

Elsewhere over the South Pacific Ocean Tropical Cyclone Josie was swirling south of Fiji.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Josie was located at latitude 21.1°S and longitude 178.1°E which put it about 185 miles (300 km) south of Suva, Fiji.  Josie was moving toward the south-southeast at 14 m.p.h. (22 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 Cyclone Josie Brings Wind and Rain to Fiji

Tropical Cyclone Josie brought wind and rain to Fiji on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Josie was located at latitude 19.2°S and longitude 177.4°E which put it about 105 miles (170 km) southwest of Suva, Fiji.  Josie was moving toward the east-southeast at 14 m.p.h. (22 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 998 mb.

Tropical Cyclone Josie formed within an area of thunderstorms that had persisted west of Fiji for several days.  A center of circulation developed within the area of thunderstorms and the Fiji Meteorological Service designated the system as Tropical Cyclone Josie.  The circulation of Tropical Cyclone Josie was somewhat asymmetrical.  Most of the stronger thunderstorms were occurring in the eastern half of the circulation.  The strongest winds were occurring in a primary rainband east of the center of circulation,  The bands in the western half of the circulation consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out about 160 miles (260 km) east of the center of circulation.

Tropical Cyclone Josie will move through an area somewhat favorable for intensification during the next day or two.  Josie will move over water where the Sea Surface Temperature is near 28°C.  It will move near an area where westerly winds are blowing in the upper levels and those winds may already be responsible for the asymmetrical distribution of stronger storms.  The upper level winds will cause moderate vertical wind shear, but the shear may not be strong enough to prevent some intensification.  Tropical Cyclone Josie could intensify slowly during the next 24 to 48 hours.

Tropical Cyclone Josie is moving near the eastern end of a ridge which is steering Josie toward the east-southeast.  The westerly winds in the middle troposphere will continue to steer Tropical Cyclone Josie toward the southeast during the next several days.  On its anticipated track the center of Josie will pass south of Viti Levu.  The center of Tropical Cyclone Josie will move near Kadavu and Ono in about 12 hours.  Even though the center of circulation will pass south of Viti Levu, Tropical Cyclone Josie will drop heavy rain there and the potential for flash floods will exist.  Josie will also bring gusty winds and heavy rain to Kadavu and Ono.