Tag Archives: HWISI

Hurricane Warning for Azores for Gabrielle

A Hurricane Warning is in effect for all of the Azores for Hurricane Gabrielle.  At 8:00 a.m. EDT on Wednesday the center of Hurricane Gabrielle was located at latitude 35.8°N and longitude 50.2°W which put the center about 1285 miles (2070 km) west of the Azores.  Gabrielle was moving toward the east-northeast at 25 m.p.h. (40 km/h).  The maximum sustained wind speed was 115 m.p.h. (1850 km/h) and there were wind gusts to 135 m.p.h. (220 km/h).  The minimum surface pressure was 960 mb.

A Hurricane Warning is in effect for all of the Azores.

Hurricane Gabrielle was speeding toward the Azores on Wednesday morning.  Gabrielle was still a major hurricane.  An eye was still present at the center of Gabrielle’s circulation, but there were some clouds in the eye.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Gabrielle’s circulation.  Storms near the center of Gabrielle generated upper level divergence that pumped mass away from the hurricane.  The removal of mass in the upper level was slightly less than the inflow of mass in the lower levels of the atmosphere.  The stronger inflow of mass in the lower levels caused the surface pressure to increase gradually.

The size of the circulation around Hurricane Gabrielle did not change much during the past 24 hours.  Winds to hurricane force extended out 45 miles (75 km) from the center of Gabrielle’s circulation.  Winds to tropical storm force extended out 140 miles (225 km) from the center of Hurricane Gabrielle.

The Hurricane Intensity Index (HII) for Hurricane Gabrielle is 20.6.  The Hurricane Size Index (HSI) is 15.5 and the Hurricane Wind Intensity Size Index (HWISI) is 36.1. Hurricane Gabrielle is similar in size and intensity to Hurricane Delta when Delta hit Louisiana in 2020.

Hurricane Gabrielle will move through an environment that will be unfavorable for intensification of a hurricane during the next 24 hours.  Gabrielle will move over water where the Sea Surface Temperatures are near 26°C.  It will move under the southern extent of the upper level westerly winds in the middle latitudes.  Those upper level westerly winds will cause moderate vertical wind shear.  Hurricane Gabrielle will continue to weaken gradually during the next 24 hours.

The upper level westerly winds in the middle latitudes will steer Hurricane Gabrielle toward the east during the next 24 hours.  On its anticipated track, Hurricane Gabrielle will reach the Azores on Thursday.

Hurricane Gabrielle will bring strong winds and heavy rain to the Azores on Thursday night and Friday.

Typhoon Ragasa Brings Wind and Rain to Hong Kong

Typhoon Ragasa brought wind and rain to Hong Kong on Tuesday night.  At 11:00 p.m. EDT on Tuesday the center of Typhoon Ragasa was located at latitude 21.3°N and longitude 113.2°E which put the center about 80 miles (130 km) south-southwest of Hong Kong.  Ragasa was moving toward the west at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 155 m.p.h. (250 km/h).  The minimum surface pressure was 944 mb.

The center of Typhoon Ragasa passed south of Hong Kong on Tuesday night.  A weather station at the airport in Hong Kong (VHHH) reported a sustained wind speed of 47 kt (54 m.p.h. or 87 km/h) and a wind gust of 66 kt (76 m.p.h. or 122 km/h).

The inner end of a rainband wrapped around the existing eye and eyewall in Typhoon Ragasa as it was passing south of Hong Kong.  A second outer eyewall appeared to be developing.  The formation of concentric eyewalls could start another eyewall replacement cycle.  Bands of showers and thunderstorms were revolving around the core of Typhoon Ragasa.  Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The circulation around Typhoon Ragasa was large.  Winds to typhoon force extended out 60 miles (95 km) from the center of Ragasa’s circulation.  Winds to tropical storm force extended out 190 miles (305 km) from the center of Typhoon Ragasa.

The Hurricane Intensity Index (HII) for Typhoon Ragasa is 25.1.  The Hurricane Size Index (HSI) is 20.8 and the Hurricane Wind Intensity Size Index (HWISI) is 45.9.  Typhoon Ragasa is similar in intensity to Hurricane Harvey when Harvey hit Texas in 2017.  Ragasa is larger than Harvey was.

Typhoon Ragasa will move through an environment that will be favorable for a powerful typhoon during the next few hours.  Ragasa will move over water where the Sea Surface Temperatures are near 29°C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Even though Typhoon Ragasa will move through a favorable environment, another eyewall replacement cycle would cause Ragasa to weaken.

Typhoon Ragasa will move around the southern side of a high pressure system over China.  The high pressure system will steer Ragasa toward the west during the next 24 hours.  On its anticipated track, the center of Typhoon Ragasa will make landfall on the coast of southern China west of Macau in 12 hours.

Typhoon Ragasa will bring strong winds and heavy rain to Guangxi and to western Guangdong.  Heavy rain is likely to cause floods in some locations.  Typhoon Ragasa could cause a storm surge of up to 13 feet (4 meters) along portions of the coast.  Ragasa could also drop heavy rain over northern parts of Vietnam and Laos.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Bualoi formed east of the Philippines and former Typhoon Neoguri weakened to a tropical storm far to the east of Japan.

At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Bualoi was located at latitude 9.5°N and longitude 133.4°E which put the center about 535 miles (865 km) east of Surigao, Philippines.  Bualoi was moving toward the west-southwest at 11 m.p.h. (17 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 1002 mb.

At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Neoguri was located at latitude 30.6°N and longitude 154.6°E which put the center about 910 miles (1465 km) east-southeast of Tokyo, Japan.  Neoguri was moving toward the east at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 978 mb.

Gabrielle Prompts Hurricane Watch for the Azores

The risk posed by Hurricane Gabrielle prompted the issuance of a Hurricane Watch for the Azores on Tuesday.  At 2:00 p.m. EDT on Tuesday the center of Hurricane Gabrielle was located at latitude 34.3°N and longitude 57.5°W which put the center about 1710 miles (2755 km) west of the Azores.  Gabrielle was moving toward the east-northeast at 20 m.p.h. (32 km/h).  The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 155 m.p.h. (250 km/h).  The minimum surface pressure was 952 mb.

A Hurricane Watch is in effect for all of the Azores.

A circular eye with a diameter of 20 miles (32 km) was at the center of Gabrielle’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Gabrielle’s circulation.  Storms near the center of Gabrielle generated upper level divergence that pumped mass away from the hurricane.  The removal of mass in the upper level was slightly less than the inflow of mass in the lower levels of the atmosphere.  The strong inflow of mass in the lower levels caused the surface pressure to increase gradually.

The size of the circulation around Hurricane Gabrielle did not change much during the past 24 hours.  Winds to hurricane force extended out 40 miles (65 km) from the center of Gabrielle’s circulation.  Winds to tropical storm force extended out 140 miles (225 km) in the western side of Hurricane Gabrielle.  Winds to tropical storm force extended out 70 miles (110 km) in the eastern side of Gabrielle’s circulation.

The Hurricane Intensity Index (HII) for Hurricane Gabrielle was 25.1.  The Hurricane Size Index (HSI) was 12.9 and the Hurricane Wind Intensity Size Index (HWISI) was 38.0.  Hurricane Gabrielle was similar in size and intensity to Hurricane Harvey when Harvey hit Texas in 2017.

Hurricane Gabrielle will move through an environment that will become more unfavorable for intensification during the next 24 hours.  Gabrielle will move over water where the Sea Surface Temperatures are near 27°C.  It will move under the southern extent of the upper level westerly winds in the middle latitudes.  Those upper level westerly winds will cause the vertical wind shear to increase.  Hurricane Gabrielle will continue to weaken gradually during the next 24 hours.

The upper level westerly winds in the middle latitudes will steer Hurricane Gabrielle toward the east during the next 24 hours.  On its anticipated track, Hurricane Gabrielle will reach the Azores on Thursday.

Hurricane Gabrielle will bring strong winds and heavy rain to the Azores on Thursday night and Friday.

Typhoon Ragasa Moves over South China Sea

Typhoon Ragasa moved over the South China Sea on Monday night.  At 11:00 p.m. EDT on Monday the center of Typhoon Ragasa was located at latitude 20.2°N and longitude 117.7°E which put the center about 300 miles (485 km) east-southeast of Hong Kong.  Ragasa was moving toward the west at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 145 m.p.h. (235 km/h) and there were wind gusts to 175 m.p.h. (280 km/h).  The minimum surface pressure was 930 mb.

Typhoon Ragasa went through an eyewall replacement cycle, but the eyewall replacement only weakened Ragasa slightly.  A new eye with a diameter of 30 miles (50 km) was at the center of Ragasa’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Typhoon Ragasa.  Storms near the center of Ragasa generated strong upper level divergence that pumped mass away in all directions from the typhoon.  The removal of large quantities of mass in the upper levels was slightly less than the inflow of mass in the lower levels of the atmosphere.  The inflow of mass in the lower levels caused the surface pressure to increase slowly.

The circulation around Typhoon Ragasa was large.  Winds to typhoon force extended out 80 miles (130 km) from the center of Ragasa’s circulation.  Winds to tropical storm force extended out 240 miles (390 km) from the center of Typhoon Ragasa.

The Hurricane Intensity Index (HII) for Typhoon Ragasa was 29.9.  The Hurricane Size Index (HSI) was 28.7 and the Hurricane Wind Intensity Size Index (HWISI) was 58.6.  Typhoon Ragasa was larger and stronger than Hurricane Helene was when Helene hit Florida in 2024.

Typhoon Ragasa will move through an environment that will be favorable for a powerful typhoon during the next 24 hours.  Ragasa will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the southern part of an upper level ridge over China.  The upper level ridge will produce easterly winds that will blow toward the top of Ragasa’s circulation.  Those winds will cause the vertical wind shear to increase.  Typhoon Ragasa could weaken slowly during the next 24 hours because of more vertical wind shear.

Typhoon Ragasa will move around the southern side of a high pressure system over China.  The high pressure system will steer Ragasa toward the west-northwest during the next 24 hours.  On its anticipated track, the center of Typhoon Ragasa will be just south of Hong Kong in less than 24 hours.

Typhoon Ragasa will bring strong winds and locally heavy rain to coastal regions in southern China including Hong Kong.  Heavy rain is likely to cause flash floods in some locations.  Typhoon Ragasa could also cause a storm surge of up to 13 feet (4 meters) along parts of the coast.

Elsewhere over the Western North Pacific Ocean, Typhoon Neoguri moved farther east of Japan.  At 11:00 p.m. EDT on Monday the center of Typhoon Neoguri was located at latitude 30.6°N and longitude 153.3°E which put the center about 910 miles (1470 km) east of Tokyo, Japan.  Neoguri was moving toward the east-northeast at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 963 mb.

Hurricane Gabrielle Strengthens to Cat. 4

Hurricane Gabrielle strengthened to Category 4 on the Saffir-Simpson Scale east of Bermuda on Monday afternoon.  At 5:00 p.m. EDT on Monday the center of Hurricane Gabrielle was located at latitude 31.7°N and longitude 61.8°W which put the center about 180 miles (290 km) east-southeast of Bermuda.  Gabrielle was moving toward the north-northeast at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 140 m.p.h. (225 km/h) and there were wind gusts to 165 m.p.h. (265 km/h).  The minimum surface pressure was 948 mb.

Hurricane Gabrielle strengthened to Category 4 on the Saffir-Simpson Scale east of Bermuda on Monday afternoon.  A circular eye with a diameter of 20 miles (32 km was at the center of Gabrielle’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Gabrielle’s circulation.  Storms near the center of Gabrielle generated upper level divergence that pumped mass away from the hurricane.  The removal of mass caused the surface pressure to decrease.

The size of the circulation around Hurricane Gabrielle increased on Monday.  Winds to hurricane force extended out 40 miles (65 km) from the center of Gabrielle’s circulation.  Winds to tropical storm force extended out 140 miles (225 km) in the western side of Hurricane Gabrielle.  Winds to tropical storm force extended out 70 miles (110 km) in the eastern side of Gabrielle’s circulation.

The Hurricane Intensity Index (HII) for Hurricane Gabrielle was 28.6.  The Hurricane Size Index (HSI) was 13.1 and the Hurricane Wind Intensity Size Index (HWISI) was 41.7.

Hurricane Gabrielle will move through an environment that will become unfavorable for intensification during the next 24 hours.  Gabrielle will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the southern extent of the upper level westerly winds in the middle latitudes.  Those upper level westerly winds will cause the vertical wind shear to increase.  Hurricane Gabrielle will start to weaken when the wind shear increases.

The upper level westerly winds in the middle latitudes will steer Hurricane Gabrielle toward the east during the next 24 hours.  On its anticipated track, Hurricane Gabrielle will move away from Bermuda on Tuesday.  Gabrielle will approach the Azores on Thursday.

 

Gabrielle Rapidly Intensifies to Major Hurricane

Hurricane Gabrielle rapidly intensified to a major hurricane southeast of Bermuda on Monday morning.  At 9:00 a.m. EDT on Monday the center of Hurricane Gabrielle was located at latitude 30.6°N and longitude 62.2°W which put the center about 195 miles (310 km) southeast of Bermuda.  Gabrielle was moving toward the north at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 145 m.p.h. (235 km/h).  The minimum surface pressure was 957 mb.

Hurricane Gabrielle rapidly intensified to a major hurricane southeast of Bermuda on Monday morning.  A small circular eye formed at the center of Gabrielle’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Gabrielle’s circulation.  Storms near the center of Gabrielle generated strong upper level divergence that pumped mass away from the hurricane.  The removal of large quantities of mass caused the surface pressure to decrease rapidly.

The circulation around Hurricane Gabrielle became more symmetrical on Monday morning.  Winds to hurricane force extended out 30 miles (50 km) from the center of Gabrielle’s circulation.  Winds to tropical storm force extended out 140 miles (220 km) from the center of Hurricane Gabrielle.

The Hurricane Intensity Index (HII) for Hurricane Gabrielle was 22.1.  The Hurricane Size Index (HSI) was 9.9 and the Hurricane Wind Intensity Size Index (HWISI) was 32.0.  Hurricane Gabrielle was similar in size and intensity to Hurricane Dennis when Dennie hit Northwest Florida in 2005.

Hurricane Gabrielle will move through an environment favorable for intensification during the next 24 hours.  Gabrielle will move over water where the Sea Surface Temperatures are near 29°C.  It will move in the region between an upper level low south of Bermuda and an upper level trough near the east coast of the U.S.  The upper level winds are weak between the upper level low and the upper level trough.  So, there will be little vertical wind shear. Hurricane Gabrielle will intensify during the next 24 hours.  Gabrielle could continue to intensify rapidly during the next few hours .

Hurricane Gabrielle will move around the western end of a subtropical high pressure system over the Atlantic Ocean. The high pressure system will steer Gabrielle toward the north during the next 24 hours.  On its anticipated track, Hurricane Gabrielle will pass east of Bermuda later on Monday.  Gabrielle could approach the Azores by Thursday evening.

Typhoon Ragasa Hammers Babuyan Islands

Typhoon Ragasa hammered the Babuyan Islands just north of Luzon on Sunday night.  At 5:00 a.m. EDT on Mounday the center of Typhoon Ragasa was located at latitude 19.4°N and longitude 121.1°E which put the center about 50 miles (80 km) north of Claveria, Philippines.  Ragasa was moving toward the west at 12 m.p.h. (19 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 916 mb.

Typhoon Ragasa was the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale when it hit the Babuyan Islands just north of Luzon on Sunday night.  The eye at the center of Ragasa’s circulation passed over Babuyan Island.  Typhoon Ragasa brought potentially catastrophic winds and heavy rain to the island.  Ragasa could also have caused a storm surge of up to 16 feet (5 meters) along the coast of the island.

Typhoon Ragasa was still the equivalent of a Category 5 hurricane on Monday morning.  A circular eye with a diameter of 35 miles (55 km) was at the center of Ragasa’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Typhoon Ragasa.  Storms near the center of Ragasa generated strong upper level divergence that pumped mass away in all directions from the typhoon.  The removal of large quantities of mass in the upper levels was nearly equal to the inflow of mass in the lower levels of the atmosphere.  The balance of inflow and outflow of mass caused the surface pressure to remain nearly constant.

The circulation around Typhoon Ragasa was large.  Winds to typhoon force extended out 80 miles (130 km) from the center of Ragasa’s circulation.  Winds to tropical storm force extended out 250 miles (400km) from the center of Typhoon Ragasa.

The Hurricane Intensity Index (HII) for Typhoon Ragasa was 35.0.  The Hurricane Size Index (HSI) was 28.4 and the Hurricane Wind Intensity Size Index (HWISI) was 63.4.  Typhoon Ragasa was similar in intensity to Hurricane Maria when Maria hit Puerto Rico in 2017.  Ragasa was bigger than Maria was.

Typhoon Ragasa will move through an environment very favorable for a powerful typhoon during the next 24 hours.  Ragasa will move over water where the Sea Surface Temperatures are near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Typhoon Ragasa could maintain its intensity during the next 24 hours unless an eyewall replacement cycle occurs.

Typhoon Ragasa will move around the southern side of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Ragasa toward the west during the next 24 hours.  On its anticipated track, the center of Typhoon Ragasa will be south of Hong Kong in 48 hours.

Typhoon Ragasa will continue to produce very strong winds and heavy rain in the Batanes Islands and to the Babuyan Island until it moves farther to the west of those islands.   Typhoon Ragasa is likely to cause catastrophic damage on those islands.  Typhoon Ragasa will also continue to cause strong winds and heavy rain in northern Luzon.  Heavy rain could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, Typhoon Neoguri weakened slightly far to the east of Japan.  At 5:00 a.m. EDT on Monday the center of Typhoon Neoguri was located at latitude 30.3°N and longitude 152.0°E which put the center about 825 miles (1330 km) east of Tokyo, Japan.  Neoguri was moving toward the northeast at 11 m.p.h. (17 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 950 mb.

Typhoon Ragasa Intensifies to Equivalent of Cat. 5 Hurricane

Typhoon Ragasa intensified to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale on Saturday night east of northern Luzon.  At 5:00 a.m. EDT on Sunday the center of Typhoon Ragasa was located at latitude 18.5°N and longitude 125.8°E which put the center about 280 miles (455 km) east of Aparri, Philippines.  Ragasa was moving toward the west-northwest at 8 m.p.h. (13 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 922 mb.

Typhoon Ragasa intensified to the equivalent of a Category 5 hurricane on Saturday night.  A small circular eye was at the center of Ragasa’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Typhoon Ragasa.  Storms near the center of Ragasa generated strong upper level divergence that pumped mass away in all directions from the typhoon.  The removal of large quantities of mass caused the surface pressure to decrease rapidly.

The circulation around Typhoon Ragasa was large.  Winds to typhoon force extended out 60 miles (95 km) from the center of Ragasa’s circulation.  Winds to tropical storm force extended out 215 miles (345 km) from the center of Typhoon Ragasa.

The Hurricane Intensity Index (HII) for Typhoon Ragasa was 35.0.  The Hurricane Size Index (HSI) was 20.6 and the Hurricane Wind Intensity Size Index (HWISI) was 55.6.  Typhoon Ragasa was similar in size and intensity to Hurricane Maria when Maria hit Puerto Rico in 2017.

Typhoon Ragasa will move through an environment very favorable for a powerful typhoon during the next 24 hours.  Ragasa will move over water where the Sea Surface Temperatures are near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Typhoon Ragasa could continue to intensify during the next 24 hours unless an eyewall replacement cycle occurs.

Typhoon Ragasa will move around the southern side of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Ragasa toward the west-northwest during the next 24 hours.  On its anticipated track, the center of Typhoon Ragasa will be north of Luzon in 24 hours.

Typhoon Ragasa will bring very strong winds and heavy rain to the Batanes Islands and to the Babuyan Islands.  Ragasa could cause a storm surge of up to 16 feet (5 meters).  Typhoon Ragasa could cause catastrophic damage on those islands.  Typhoon Ragasa will also cause strong winds and heavy rain in northern Luzon.  Heavy rain could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, powerful Typhoon Neoguri continued to spin far to the southeast of Japan.  At 5:00 a.m. EDT on Sunday the center of Typhoon Neoguri was located at latitude 28.0°N and longitude 151.6°E which put the center about 880 miles (1420 km) east-southeast of Tokyo, Japan.  Neoguri was moving toward the northwest at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 145 m.p.h. (235 km/h) and there were wind gusts to 175 m.p.h. (280 km/h).  The minimum surface pressure was 936 mb.

Typhoon Ragasa Rapidly Intensifies to Equivalent of Major Hurricane

Typhoon Ragasa rapidly intensified to the equivalent of a major hurricane east of northern Luzon on Saturday.  At 11:00 a.m. EDT on Saturday the center of Typhoon Ragasa was located at latitude 17.4°N and longitude 128.4°E which put the center about 475 miles (765 km) east of Aparri, Philippines.  Ragasa was moving toward the northwest at 7 m.p.h. (11 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. (235 km/h).  The minimum surface pressure was 957 mb.

Typhoon Ragasa rapidly intensified to the equivalent of a major hurricane east of northern Luzon on Saturday.  A small circular eye was present at the center of Ragasa’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Typhoon Ragasa.  Storms near the center of Ragasa generated strong upper level divergence that pumped mass away in all directions from the typhoon.  The removal of large quantities of mass caused the surface pressure to decrease rapidly.

The circulation around Typhoon Ragasa was large.  Winds to typhoon force extended out 70 miles (110 km) from the center of Ragasa’s circulation.  Winds to tropical storm force extended out 275 miles (445 km) in the southern half of Typhoon Ragasa.  Winds to tropical storm force extended out 165 miles (265 km) in the northern side of Ragasa’s circulation.

The Hurricane Intensity Index (HII) for Typhoon Ragasa was 20.6.  The Hurricane Size Index (HSI) was 20.3 and the Hurricane Wind Intensity Size Index (HWISI) was 40.9.  Typhoon Ragasa was similar in intensity to Hurricane Rita when Rita hit southwest Louisiana in 2005.  Ragasa was not as large as Rita was.

Typhoon Ragasa will move through an environment very favorable for intensification during the next 24 hours.  Ragasa will move over water where the Sea Surface Temperatures are near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Typhoon Ragasa will intensify during the next 24 hours.  Ragasa could continue to intensify rapidly.  Typhoon Ragasa could strengthen to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale.

Typhoon Ragasa will move around the southern side of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Ragasa toward the west-northwest during the next 24 hours.  On its anticipated track, the center of Typhoon Ragasa will be north of Luzon in 48 hours.

Typhoon Ragasa will bring very strong winds and heavy rain to the Batanes Islands and to the Babuyan Islands.  Ragasa could cause a storm surge of up to 16 feet (5 meters.  Typhoon Ragasa could cause catastrophic damage on those islands.  Typhoon Ragasa will also cause strong winds and heavy rain in northern Luzon.  Heavy rain could cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, Typhoon Neoguri continued to strengthen southeast of Japan.  At 11:00 a.m. EDT on Saturday the center of Typhoon Neoguri was located at latitude 26.5°N and longitude 154.5°E which put the center about 1100 miles (1775 km) east-southeast of Tokyo, Japan.  Neoguri was moving toward the west-northwest at 12 m.p.h. (19 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 955 mb.

Hurricane Kiko Weakens

Hurricane Kiko weakened east of Hawaii on Sunday.  At 5:00 p.m. EDT on Sunday the center of Hurricane Kiko was located at latitude 18.1°N and longitude 145.5°W which put the center about 635 miles (1025 km) east of Hilo Hawaii. Kiko was moving toward the west-northwest at 13 m.p.h. (21 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 974 mb.

Hurricane Kiko weakened east of Hawaii on Sunday as it moved over water where the Sea Surface Temperature was near 26°C.  A circular eye was still present at the center of Kiko’s circulation, but low clouds were starting to appear inside the eye.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Storms near the center of Kiko generated upper level divergence that pumped mass away from the hurricane.  However, more mass was converging in the lower levels of the atmosphere than was being pumped away in the upper levels.  So, the surface pressure was increasing.

The circulation around Hurricane Kiko was small.  Winds to hurricane force extended out 30 miles (50 km) from the center of Kiko’s circulation.  Winds to tropical storm force extended out 80 miles (130 km) from the center of Hurricane Kiko.

The Hurricane Intensity Index (HII) for Hurricane Zeta was 19.2.  The Hurricane Size Index (HSI) was 9.1 and the Hurricane Wind Intensity Size Index (HWISI) was 28.3. Hurricane Kiko was similar in size and intensity to Hurricane Zeta when Zeta hit Louisiana in 2020.

Hurricane Kiko will move through an environment that will become even more unfavorable for intensification during the next 24 hours.  Kiko will move over water where the Sea Surface Temperatures are near 26°C.  The water just to the north of Kiko’s forecast track is even colder. It will move under the southeastern part of an upper level low that is north of Hawaii.  The upper level low will produce southwesterly winds that will blow toward the top of Kiko’s circulation.  Those winds will cause the vertical wind shear to increase.  The combination of marginal Sea Surface Temperatures and more vertical wind shear will cause Hurricane Kiko to continue to weaken during the next 24 hours.

Hurricane Kiko will move around the southwestern part of a high pressure system over the Eastern North Pacific Ocean.  The high pressure system will steer Kiko toward the west-northwest during the next 24 hours.  On its anticipated track, Hurricane Kiko will be northeast of Hawaii on Monday night.