Tag Archives: HWISI

Isaias Strengthens Back into a Hurricane

Isaias strengthened back into a hurricane on Monday evening.  At 9:00 p.m. EDT on Monday the center of Hurricane Isaias was located at latitude 33.1°N and longitude 78.8°W which put it about 55 miles (90 km) south-southeast of Myrtle Beach, South Carolina.  Isaias was moving toward the north-northeast at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 988 mb.

A Hurricane Warning was in effect for the portion of the coast from South Santee River, South Carolina to Surf City, North Carolina.  Tropical Storm Warnings were in effect for the portion of the coast from Edisto Beach to South Santee River, South Carolina and from Surf City, North Carolina to Stonington, Maine including Albemarle Sound, Pamlico Sound, Long Island, Long Island Sound, Block Island, Martha’s Vineyard, and Nantucket.  A Tropical Storm Watch was in effect for the portion of the coast from Stonington, to Eastport, Maine.

The circulation around Hurricane Isaias became much better organized on Monday afternoon.  A reconnaissance aircraft investigating Isaias found winds to hurricane force.  An elliptical eye developed at the center of Hurricane Isaias.  A broken ring of thunderstorms surrounded the elliptical eye and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Isaias.  The strongest rainbands were in the northern half of the circulation.  Bands in the southern half of Hurricane Isaias consisted primarily of showers and lower clouds.  Winds to hurricane force extended out 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out 125 miles (200 km) from the center.

The Hurricane Intensity Index (HII) for Hurricane Isaias was 12.7.  The Hurricane Size Index (HSI) was 15.3 and the Hurricane Wind Intensity Size Index (HWISI) was 28.0.  Hurricane Isaias was capable of causing regional minor damage.

The center of Hurricane Isaias will make landfall between Myrtle Beach, South Carolina and Southport, North Carolina during the next few hours.  Isaias will bring hurricane force winds to the portion of the coast from Myrtle Beach, South Carolina to Surf City, North Carolina.  It will generate a storm surge of 3 to 6 feet (1 to 2 meters) along the coast.  Hurricane Isaias will drop heavy rain over extreme eastern South Carolina, eastern North Carolina and eastern Virginia.  Heavy rain could cause flooding in some locations.

The center of Hurricane Isaias will pass just west of Norfolk, Virginia on Tuesday morning.  isaias will weaken when it passes over land, but it will still bring gusty winds over eastern Virginia.  Isaias will pass near New York City on Tuesday evening and it will bring gusty winds to New England on Tuesday night.  Isaias could cause widespread power outages along the East Coast of the U.S.  It will also drop heavy rain east of the Appalachians and flash floods could occur in that region.

Typhoon Hagupit Makes Landfall in China

Typhoon Hagupit made landfall in China on Monday.  At 5:00 p.m. EDT on Monday the center of Typhoon Hagupit was located at latitude 28.3°N and longitude 120.8°E which put it about 50 miles (80 km) south-southwest of Taizhou, China and about 235 miles (375 km) south of Shanghai.  Hagupit was moving toward the north-northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 978 mb.

Former Tropical Storm Hagupit strengthened quickly to a typhoon before it made landfall on the east coast of China.  A circular eye formed at the center of circulation.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storm.  Winds to typhoon force extended out 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out 135 miles (220 km) from the center.

The Hurricane Intensity Index (HII) for Typhoon Hagupit was 11.5.  The Hurricane Size Index (HSI) was 12.0 and the Hurricane Wind Intensity Size Index (HWISI) was 23.5.  Typhoon Hagupit was capable of causing regional minor damage.

Typhoon Hagupit will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Hagupit toward the north during the next 24 hours.  On its anticipated track the center of Typhoon Hagupit will pass west of Shanghai in 18 to 24 hours.  Hagupit will bring gusty winds and locally heavy rain to Zhejiang and Jiangsu. Heavy rain could cause flash floods in some locations.  Typhoon Hagupit will also cause a storm surge along the coast of Zhejiang, Jiangsu and Shanghai Shi.

Tropical Cyclone Amphan Intensifies Into Equivalent of Cat. 5 Hurricane

Tropical Cyclone Amphan intensified into equivalent of a Category 5 hurricane on the Saffir-Simpson Scale over the Bay of Bengal on Monday.  At 5:00 a.m. EDT on Monday the center of Tropical Cyclone Amphan was located at latitude 13.9°N and longitude 86.5°E which put it about 635 miles (1025 km) south-southwest of Kolkata, India.  Amphan was moving toward the north 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 909 mb.

The circulation around Tropical Cyclone Amphan appeared to develop a concentric eyewall structure on Monday.  The inner end of a rainband wrapped around the original small eye and eyewall.  The inner eye had a diameter of 10 miles (16 km).  A ring of strong thunderstorms surrounded the inner eye and the strongest winds were occurring in that ring of storms.  An outer eyewall with a diameter of 50 mile (80 km) surrounded the inner eye.    Bands of showers and thunderstorms were revolving around the concentric eyewalls.  Storms in the core of Amphan were generating strong upper level divergence which was pumping mass away from the tropical cyclone in all directions.

Tropical Cyclone Amphan had a large circulation.  Winds to hurricane/typhoon force extended out 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out 200 miles (325 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Amphan was 35.0.  The Hurricane Size Index (HSI) was 16.5 and the Hurricane Wind Intensity Size Index (HWISI0 was 51.5.  Tropical Cyclone Amphan was capable of causing catastrophic damage.

Tropical Cyclone Amphan will move through an environment very favorable for a strong tropical cyclone during the next 36 hours.  Amphan will move over water where the Sea Surface Temperature is near 31°C.  It will move under an upper level ridge where the upper level winds are weak.  There will be little vertical wind shear.  The eyewall replacement cycle will stop the intensification of Tropical Cyclone Amphan.  Amphan will weaken, at least temporarily, when the inner eyewall dissipates.  When that occurs the strongest winds will be occurring in the outer eyewall.  The eyewall replacement cycle could cause the circulation to increase in size.

Tropical Cyclone Amphan will move around the western end of a high pressure system over Southeast Asia.  The high will steer Amphan toward the north-northeast.  On its anticipate track the center of Tropical Cyclone Amphan will approach the coast around the northern Bay of Bengal in 36 hours.  Amphan will be a large dangerous tropical cyclone when it approaches the coast.  Tropical Cyclone Amphan will generate a significant storm surge along the coast of Bangladesh.  Amphan will cause major wind damage.  It will drop locally heavy rain over northeast India and Bangladesh.  Freshwater flooding will occur.

Tropical Cyclone Amphan Rapidly Intensifies Into Equivalent of Major Hurricane

Tropical Cyclone Amphan rapidly intensified into the equivalent of a major hurricane over the Bay of Bengal on Sunday night.  At 11:00 p.m. EDT on Sunday the center of Tropical Cyclone Amphan was located at latitude 13.3°N and longitude 86.4°E which put it about 675 miles (1090 km) south-southwest of Kolkata, India.  Amphan was moving toward the north at 5 m.p.h. (8 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 919 mb.

Tropical Cyclone Amphan rapidly intensified into a large powerful tropical cyclone on Sunday night.  A small circular eye was 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 Amphan.  Storms near the core were generating strong upper level divergence which was pumping mass away from the tropical cyclone in all directions.

The circulation around Tropical Cyclone Amphan grew in size on Sunday.  Winds to hurricane/typhoon force extended out 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out 210 miles (335 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Amphan was 31.6.  The Hurricane Size Index was 16.8 and the Hurricane Wind Intensity Size Index (HWISI) was 48.4.  Tropical Cyclone Amphan was capable of causing widespread significant damage.

Tropical Cyclone Amphan will remain in an environment capable of supporting a strong tropical cyclone during the next 36 to 48 hours.  Amphan will move over water where the Sea Surface Temperature is near 31°C.  It will move under an upper level ridge.  The upper level wind will be weak and there will be little vertical wind shear.  The ridge will actually enhance the upper level divergence.  If a rainband wraps around the existing eye and eyewall, then an eyewall replacement cycle could cause Tropical Cyclone Amphan to weaken.  Tropical Cyclone Amphan is likely to remain a large, powerful tropical cyclone during the next 48 hours.

Tropical Cyclone Amphan will move around the western end of a high pressure system over Southeast Asia.  The high will steer Amphan toward the north.  On its anticipated track Tropical Cyclone Amphan could approach the coast of Bangladesh in 48 hours.  Amphan is could still be the equivalent of a major hurricane when it reaches Bangladesh.  Tropical Cyclone Amphan could generate a significant storm surge at the coast.  Amphan will cause major wind damage and heavy rain could cause freshwater flooding.

Typhoon Vongfong Nears Landfall in Samar

Typhoon Vongfong neared landfall in Samar on Wednesday night.  At 11:00 p.m. EDT on Wednesday the center of Typhoon Vongfong was located near latitude 12.2°N and longitude 125.8°E which put it about 30 miles (50 km) east of Dolores, Philippines.  Vongfong was moving toward the west at 9 m.p.h. (15 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. (210 km/h).  The minimum surface pressure was 959 mb.

Typhoon Vongfong was a small but strong tropical cyclone.  There was a small circular eye at the center of circulation.  The eye was surrounded by a ring of strong thunderstorms.  The strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of the circulation.

Winds to typhoon force extended out 20 miles (30 km) from the center of Typhoon Vongfong.  Winds to tropical storm force extended out 75 miles (120 km) from the center.  The Hurricane Intensity Index (HII) for Vongfong was 19.2.  The Hurricane Size Index (HSI) was 5.6 and the Hurricane Wind Intensity Size Index (HWISI) was 24.8.  Typhoon Vongfong was capable of causing localized serious damage.

Typhoon Vongfong will move around the western end of a high pressure system centered southeast of Japan.  The high will steer Vongfong toward the northwest during the next 24 hours.  On its anticipated track the center of Typhoon Vongfong will make landfall on the coast of northern Samar north of Dolores during the next 6 to 12 hours.  The center of Vongfong could be near Laoang in about 12 hours.  Typhoon Vongfong could move over southeastern Luzon later on Thursday.  The center of Vongfong could be near Legaspi in 18 hours.

The small inner core of Typhoon Vongfong will be capable of causing localized serious wind damage in northern Samar and southeastern Luzon.  Vongfong could bring strong winds to Dolores, Laoang, Catarman, Bulan, Sorsogon and Legaspi.  Typhoon Vongfong will drop locally heavy rain over northern Samar, southeastern Luzon and Catanduanes Island.  Flash floods could occur in some locations.  Vongfong could cause a storm surge of up to 10 feet (3 meters) in parts of northern Samar and southeastern Luzon.

Vongfong Rapidly Intensifies Into a Typhoon East of Samar

Former Tropical Storm Vongfong rapidly intensified into a typhoon east of Samar on Wednesday.  At 11:00 a.m. EST on Wednesday the center of Typhoon Vongfong was located at latitude 12.3°N and longitude 127.6°E which put it about 140 miles (225 km) east of Dolores, Philippines.  Vongfong was moving toward the west-northwest at 7 m.p.h. (11 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. (200 km/h).  The minimum surface pressure was 966 mb.

Typhoon Vongfong rapidly intensified on Wednesday from a strong tropical storm into a typhoon.  A small circular eye formed 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 Typhoon Vongfong.  Storms near the core were generating strong upper level divergence which was pumping mass away from the typhoon in all directions.  The removal of mass was allowing the surface pressure to decrease quickly, which caused the rapid intensification.

The circulation around Typhoon Vongfong was small.  Winds to typhoon force extended out 20 miles (30 km) from the center of circulation.  Winds to tropical storm force extended out 90 miles (145 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Vongfong was 17.8.  The Hurricane Size Index (HSI) was 6.4 and the Hurricane Wind intensity Size Index (HWISI) was 24.2.  Typhoon Vongfong was capable of causing localized serious damage.

Typhoon Vongfong will move through an environment favorable for intensification during the next 24 hours.  Vongfong will move over water where the Sea Surface Temperature is near 29.5°C.  It will move under a small upper level ridge east of the Philippines.  The upper level winds in the ridge are weak and there will be little vertical wind shear.  Typhoon Vongfong will continue to intensify rapidly in the short term.  Vongfong is likely to strengthen into the equivalent of a major hurricane during the next 6 to 12 hours.

Typhoon Vongfong will move around the western end of a high pressure system centered southeast of Japan.  The high will steer Vongfong toward the west-northwest during the next 24 hours.  Typhoon Vongfong will start to move more toward the north-northwest in a day or so, when it nears the western end of the high pressure system.  On its anticipated track the core of Typhoon Vongfong could approach northern Samar in about 18 hours.  Vongfong could approach Catanduanes Island and southeastern Luzon in about 24 hours.  Outer bands on the western side of Typhoon Vongfong could start to drop heavy rain over parts of Samar during the next 12 to 18 hours.

Tropical Cyclone Harold Strengthens to Equivalent of Cat. 5 Hurricane

Tropical Cyclone Harold strengthened to the equivalent of a Category 5 hurricane on Monday.  After weakening while the eye crossed the southern end of Espiritu Santo, the core of Harold rapidly intensified and the tropical cyclone became even more powerful.  At 11:00 a.m. EDT on Monday the center of Tropical Cyclone Harold was located at latitude 16.2°S and longitude 169.4°E which put it about 120 miles (195 km) north-northeast of Port Vila, Vanuatu.  Harold was moving toward the east-southeast at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 165 m.p.h.  and there were wind gusts to 200 m.p.h. (320 km/h).  The minimum surface pressure was 912 mb.

The inner core of Tropical Cyclone Harold weakened when the eye moved across the southern end of Espiritu Santo.  For a time the eye was less distinct of satellite images.  However, the eye cleared out quickly after it moved back over water and the core of Harold strengthened further.  By Monday a small, well formed eye was evident infrared satellite images.  The eye had a diameter of 12 miles (19 km).  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 Tropical Cyclone Harold.  Storms near the core were generating strong upper level divergence which was pumping mass away from the tropical cyclone.

Winds to hurricane/typhoon force extended out 40 miles (65 km) from the center of Tropical Cyclone Harold.  Winds to tropical storm force extended out 190 miles (305 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Tropical Cyclone Harold was 36.8.  The Hurricane Size Index (HSI) was 16.0 and the Hurricane Wind Intensity Size Index (HWISI) was 52.8.  Harold was capable of causing catastrophic damage.

The core of Tropical Cyclone Harold passed over the southern end of Espiritu Santo.  It then passed near the northern end of Malekula before battering Pentecost and Ambrym.  Harold likely caused catastrophic wind damage in those locations.  Tropical Cyclone Harold also dropped locally heavy rain over Espiritu Santo, Malekula, Pentecost, Maewo, and Ambrym.  Flash flooding probably occurred on those islands.

Tropical Cyclone Harold will move through an environment capable of support an intense tropical cyclone during the next several days.  Harold will move over water where the Sea Surface Temperature is near 30°C.  It will move under the southwestern part of an upper level ridge over the South Pacific Ocean.  The ridge will produce northwesterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear.  If a rainband wraps around the existing eye and eyewall, then an eyewall replacement cycle could cause Tropical Cyclone Harold to weaken.  Tropical cyclones generally do not maintain Category 5 intensity for an extended period of time.  So, Tropical Cyclone Harold is likely to start to weaken within 24 hours.

Tropical Cyclone Harold will move around the southwestern part of a high pressure system over the South Pacific Ocean.  The high will steer Harold toward the east-southeast during the next few days.  On its anticipated track Tropical Cyclone Harold will move away from Vanuatu.  Harold could approach Fiji within 36 hours and it could still be the equivalent of a major hurricane at that time.

Tropical Cyclone Harold Batters Espiritu Santo

Tropical Cyclone Harold battered Espiritu Santo on Sunday.  The eye of Harold moved over the southwestern part of Espiritu Santo.  At 5:00 p.m. EDT on Sunday the center of Tropical Cyclone Harold was located at latitude 15.3°S and longitude 166.4°E which put it about 60 miles west-northwest of Luganville, Vanuatu.  Harold was moving toward the east at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 145 m.p.h. (230 km/h) and there were wind gusts to 175 m.p.h. (280 km/h).  The minimum surface pressure was 929 mb.

Tropical Cyclone Harold strengthened on Sunday as it slowly approached northern Vanuatu.  A circular eye with a diameter of 18 miles (29 km) was evident on 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 Harold.  Storms near the core were generating strong upper level divergence which was pumping mass away from the tropical cyclone.

Winds to hurricane/typhoon force extended out 45 miles (75 km) from the center of Tropical Cyclone Harold.  Winds to tropical storm force extended out 120 miles (195 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Tropical Cyclone Harold was 29.9.  The Hurricane Size Index (HSI) was 13.3 and the Hurricane Wind Intensity Size Index (HWISI) 43.2.  Harold was capable of causing significant damage.

Tropical Cyclone Harold will move around the southwestern part of a high pressure system over the South Pacific Ocean.  The high will steer Harold toward the east-southeast during the next few days.  On its anticipated track the center of Tropical Cyclone Harold will move across the southern end of Espiritu Santo.  The center will also pass near the northern end of Malekula, near the southern end of Pentecost and near Ambrym.  Tropical Cyclone Harold will drop heavy rain over Espiritu Santo, Malekula, Pentecost, Ambrym, Epi, Ambae and Maewo.  Harold will move slowly and the heavy rain is likely to cause flash floods.  Strong winds blowing toward the coast could produce significant storm surges on the eastern and northern coasts of some islands.

Tropical Cyclone Harold will move through an environment favorable for a strong tropical cyclone.  Harold will move over water where the Sea Surface Temperature is near 30°C.  It will move under the southwestern part of an upper level ridge over the South Pacific Ocean.  The ridge will produce northwesterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear.  Since the core of Tropical Cyclone Harold will pass over the southern end of Espiritu Santo, increased friction will cause the circulation to weaken during the next 12 to 24 hours.

Major Tropical Cyclone Harold Nears Vanuatu

Major Tropical Cyclone Harold neared Vanuatu on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Tropical Cyclone Vanuatu was located at latitude 15.5°S and longitude 166.0°E which put it about 80 miles (130 km) west-northwest of Unmet, Vanuatu.  Harold was moving toward the southeast 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 Harold intensified into the equivalent of a major hurricane.  The original small eye dissipated but a new larger eye developed on Saturday night.  The new eye was surround 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 Harold.  The strongest rainbands were in the eastern and southern parts of the circulation.  Storms near the core of Harold generated upper level divergence which pumped mass away from the center of the tropical cyclone.

Winds to hurricane/typhoon force extended out 30 miles (50 km) from the center of Tropical Cyclone Harold.  Winds to tropical storm force extended out 125 miles (200 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Harold was 22.1.  The Hurricane Size Index (HSI) was 11.1 and the Hurricane Wind Intensity Size Index (HWISI) was 33.2.  Tropical Cyclone Harold was capable of causing major damage.

Tropical Cyclone Harold will move through an environment favorable for intensification during the next 24 hours.  Harold will move over water where the Sea Surface Temperature is near 30°C.  It will move around the southwestern part of an upper level ridge over the South Pacific Ocean.  The ridge will produce northwesterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear and the wind shear could be strong enough to limit intensification.  Tropical Cyclone Harold could intensify further, but it may maintain its intensity on Sunday.

The ridge over the South Pacific Ocean will steer Tropical Cyclone Harold slowly toward the southeast during the next 24 hours.  On its anticipated track the core of Harold with the strongest winds will move slowly toward Malekula.  Tropical Cyclone Harold will drop heavy rain over central Vanuatu.  The slow movement of Harold could create the potential for very serious flooding on Espiritu Santo, Malekula, Ambrym and Epi.

Elsewhere in the tropics, Tropical Cyclone Irondro began to slowly weaken over the South Indian Ocean.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Irondro was located at latitude 23.3°S and longitude 81.5°E which put it about 1275 miles (2060 km) southwest of Cocos Island.  Irondro was moving toward the southeast at 18 m.p.h. (29 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. (210 km/h).  The minimum surface pressure was 958 mb.

Tropical Cyclone Harold Rapidly Intensifies into Equivalent of Hurricane/Typhoon

Tropical Cyclone Harold rapidly intensified into the equivalent of a hurricane/typhoon west-northwest of Vanuatu on Friday.  At 11:00 p.m. EDT on Friday the center of Tropical Cyclone Harold was located at latitude 14.1°S and longitude 164.1°E which put it about 170 miles (275 km) west-northwest of Nokuku, Vanuatu.  Harold was moving toward the southeast at 5 m.p.h. (8 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. (200 km/h).  The minimum surface pressure was 959 mb.

The circulation around Tropical Cyclone Harold organized quickly on Friday.  The inner end of a rainband wrapped around the center of circulation and a small eye formed.  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 Harold.  The strongest rainbands were in the eastern half of the circulation.  Bands in the western half of the circulation consisted primarily of showers and lower clouds.  Storms around the core of the circulation generated strong upper level divergence which pumped mass away to the east of the tropical cyclone.

Winds to hurricane/typhoon force extend out 35 miles (55 km) from the center of Tropical Cyclone Harold.  Winds to tropical storm force extended out 140 miles (225 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Tropical Cyclone Harold was 17.8.  The Hurricane Size Index (HSI) was 12.0 and the Hurricane Wind Intensity Size Index (HWISI) was 29.8.  Harold was capable of causing serious damage.

Tropical Cyclone Harold will move through an environment favorable for intensification during the next 24 to 48 hours.  Harold will move over water where the Sea Surface Temperature is near 30°C.  It will move around the southwestern part of an upper level ridge over the South Pacific Ocean.  The ridge will produce northwesterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification.  Tropical Cyclone Harold will strengthen into the equivalent of a major hurricane during the next 12 hours.

The upper level ridge will steer Tropical Cyclone Harold slowly toward the southeast during the weekend.  On its anticipated track Harold will gradually approach Espiritu Santo and Malekula in Vanuatu.  The core of Tropical Cyclone Harold could move across the central part of Vanuatu in 48 to 72 hours.  Harold is likely to be the equivalent of a major hurricane at that time.

Elsewhere in the tropics, Tropical Cyclone Irondro intensified into the equivalent of a hurricane/typhoon over the South Indian Ocean.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Irondro was located at latitude 19.9°S and longitude 76.4°E which put it about 885 miles (1425 km) south-southeast of Diego Garcia.  Irondro was moving toward the east-southeast at 21 m.p.h. (33 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 105 m.p.h. (170 km/h).  The minimum surface pressure was 973 mb.