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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.

Tropical Cyclone Donna Brings Wind and Rain to New Caledonia

Tropical Cyclone Donna brought wind and rain to New Caledonia as it moved over that region.  At 11:00 p.m. EDT on Monday the center of Tropical Cyclone Donna was located at latitude 19.9°S and longitude 166.8°E which put it about 185 miles (295 km) north of Noumea, New Caledonia.  Donna was moving toward the south-southeast at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (215 km/h).  The minimum surface pressure was 962 mb.

The inner core of Tropical Cyclone Donna remained intact despite increased vertical wind shear on Monday.  A well formed circular eye with a diameter of 30 miles (50 km) was evident on microwave satellite images.  A ring of strong thunderstorms wrapped around the eye.  Additional bands of showers and thunderstorms were revolving around the core of the circulation.  The size of the circulation of Tropical Cyclone Donna increased on Monday.  Winds to hurricane/typhoon force extend out about 80 miles (130 km) on the eastern side of the center and about 45 miles (75 km) on the western side.  Winds to tropical storm force extended out about 200 miles (320 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Donna was 19.2.  The Hurricane Size Index (HSI) was 23.3 and the Hurricane Wind Intensity Size Index was 42.5.  These indices suggest that Tropical Cyclone Donna is very similar in size and intensity to Hurricane Gustav in 2008 just before Gustav made landfall in Louisiana.

Tropical Cyclone Donna will weaken during the next several days.  An upper level trough is approaching it from the west.  The upper level trough is generating northwesterly winds which are blowing toward the top of the circulation.  The northwesterly winds are inhibiting upper level divergence to the west of Donna and moderate vertical wind shear will continue to weaken the tropical cyclone.  In addition Tropical Cyclone Donna will move over cooler SSTs when it moves farther south.

The winds in the upper level trough are pushing Tropical Cyclone Donna toward the south-southeast.  That general motion is expected to continue during the next several days.  On its anticipated track the core of Tropical Cyclone Donna will move over the Iles Loyaute (Loyalty Islands).  Donna will bring strong gusty winds winds to those islands.  In addition rainbands will bring wind and heavy rain to parts of New Caledonia.  Tropical Cyclone Donna is capable of causing widespread serious damage.

Powerful Tropical Cyclone Donna Moves Toward New Caledonia

Powerful Tropical Cyclone Donna moved toward New Caledonia on Sunday.  At 11:00 p.m. EDT on Sunday the center of Tropical Cyclone Donna was located at latitude 17.2°S and longitude 164.9°E which put it about 340 miles (550 km) north of Noumea, New Caledonia.  Donna was moving toward the south at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 135 m.p.h. (220 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 942 mb.

Tropical Cyclone Donna intensified rapidly into the equivalent of a major hurricane on Sunday.  The core of Donna is very well organized.  A ring of strong thunderstorms surrounds a circular eye which has a diameter of 35 miles (55 km).  Additional bands of showers and thunderstorms are occurring in the eastern half of the circulation.  Thunderstorms around the eye are generating strong upper level divergence which is pumping out mass.  Winds to hurricane/typhoon force extend out about 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extend out about 200 miles (320 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Donna was 26.7.  The Hurricane Size Index (HSI) was 17.5 and the Hurricane Wind Intensity Size Index (HWISI) was 44.2.

Tropical Cyclone Donna will move through an environment that will become less favorable for intensification during the next several days.  Donna will move over water where the Sea Surface Temperature is near 27°C.  It is currently in an area where upper level winds are weak and there is little vertical wind shear.  However, an upper level trough is approaching from the west.  Stronger northwesterly winds associated with the upper level trough will increase the vertical shear during the next several days and Tropical Cyclone Donna will weaken when the shear increases.

Donna is at the western end of a subtropical ridge which is steering the tropical cyclone slowly toward the south.  The approaching upper level trough will turn Tropical Cyclone Donna more toward the southeast in 12 to 24 hours.  On its anticipated track the center of Tropical Cyclone Donna could approach the Iles Loyaute in about 24 hours.  Donna could move near the southern portion of New Caledonia within 36 hours.

Tropical Cyclone Donna could bring strong gusty winds and locally heavy rains to portions of New Caledonia.  Donna could also generate a storm surge on the Iles Loyaute and on parts of the southern coast of New Caledonia.