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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.

Hurricane Kiko Crosses to Central Pacific

Hurricane Kiko officially crossed from the Eastern North Pacific to the Central Pacific Ocean on Saturday.  At 5:00 p.m. EDT on Saturday the center of Hurricane Kiko was located at latitude 16.1°N and longitude 141.4°W which put the center about 935 miles (1500 km) east-southeast of Hilo Hawaii.  Kiko was moving toward the west-northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 140 m.p.h. (220 km/h).  The minimum surface pressure was 954 mb.

Hurricane Kiko was gradually weakening as it crossed into the Central Pacific on Saturday.  Even though Kiko was weakening, it remained a well organized major hurricane.  A circular eye with a diameter of 15 miles (24 km) was still present at the center of Kiko’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 Hurricane Kiko.  Storms near the center generated upper level divergence that pumped mass away from the hurricane.  The removal of mass in the upper atmosphere was less than the inflow of mass in the lower levels.  So, the surface pressure was increasing gradually.

The circulation around Hurricane Kiko was small.  Winds to hurricane force extended out 25 miles (40 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 22.1.  The Hurricane Size Index (HSI) was 8.0 and the Hurricane Wind Intensity Size Index (HWISI) was 30.1.  Hurricane Kiko was similar in size to Hurricane Zeta when Zeta hit Louisiana in 2020.  Kiko was stronger than Zeta was.

Hurricane Kiko will move through an environment that will be 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 through a region where the upper level winds are weak and there will be little vertical wind shear.  Kiko will move into a region of drier air.  The combination of marginal Sea Surface Temperatures and drier air will cause Hurricane Kiko to continue to weaken gradually 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 be east of Hawaii on Sunday night.

Hurricane Kiko Churns Closer to Hawaii

Hurricane Kiko slowly churned closer to Hawaii on Friday.  At 5:00 p.m. EDT on Friday the center of Hurricane Kiko was located at latitude 14.5°N and longitude 137.8°W which put the center about 1195 miles (1925 km) east-southeast of Hilo Hawaii.  Kiko was moving toward the west-northwest at 10 m.p.h. (16 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 951 mb.

After weakening briefly earlier on Friday Hurricane Kiko strengthened back to Category 4 on the Saffir-Simpson Scale.  A circular eye with a diameter of 15 miles (24 km) was visible at the center of Kiko’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 Hurricane Kiko.  Storms near the center of Kiko generated upper level divergence that pumped mass away from the hurricane.

The circulation around Hurricane Kiko was small.  Winds to hurricane force extended out 25 miles (40 km) from the center of Kiko’s circulation.  Winds to tropical storm force extended out 70 miles (110 km) from the center of Hurricane Kiko.

The Hurricane Intensity Index (HII) for Hurricane Kiko was 25.1.  The Hurricane Size Index (HSI) was 8.5 and the Hurricane Wind Intensity Size Index (HWISI) was 33.6.  Hurricane Kiko was similar in intensity to Hurricane Harvey when Harvey hit Texas in 2017.  Kiko was not as large as Harvey was.

Hurricane Kiko will move through an environment favorable for intensification during the next 24 hours.  Kiko will move over water where the Sea Surface Temperatures are near 27°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Hurricane Kiko is likely to intensify during the next 24 hours unless an eyewall replacement cycle occurs.

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 continue to move closer to Hawaii.

 

Typhoon Kajiki Hits Northern Vietnam

Typhoon Kajiki hit the coast of northern Vietnam near Vinh early on Monday.  At 5:00 a.m. EDT on Monday the center of Typhoon Kajiki was located at latitude 18.6°N and longitude 105.7°E which put the center about 10 miles (15 km) southeast of Vinh, Vietnam.  Kajiki was moving toward the west at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 967 mb.

The center of Typhoon Kajiki hit the coast of northern Vietnam near Vinh early on Monday.  The circulation around Typhoon Kajiki was relatively small.  Winds to typhoon force extended out 40 miles (65 km/h) from the center of Kajiki’s circulation.  Winds to tropical storm force extended out 90 miles (145 km) from the center of Typhoon Kajiki.

The Hurricane Intensity Index (HII) for Typhoon Kajiki is 17.8.  The Hurricane Size Index (HSI) is 11.9 and the Hurricane Wind Intensity Size Index (HWISI) is 29.7.  Typhoon Kajiki is similar in size and intensity to Hurricane Sally when Sally hit South Alabama in 2020.

Typhoon Kajiki will move around the southern side of a high pressure system over China.  The high pressure system will steer Kajiki toward the west-northwest during the next 24 hours.  On its anticipated track, Typhoon Kajiki will move inland over northern Vietnam.  Kajiki will move over northern Laos in 12 to 18 hours.

Typhoon Kajiki will bring strong winds and locally heavy rain to northern Vietnam.  Heavy rain is likely to cause flash floods in some locations.  Kajiki will weaken steadily as it moves inland, but it could also drop heavy rain over parts of northern Laos and northern Thailand.

Typhoon Kajiki Brings Wind and Rain to Hainan

Typhoon Kajiki brought wind and rain to Hainan on Sunday.  At 5:00 a.m. EDT on Sunday the center of Typhoon Kajiki was located at latitude 17.5°N and longitude 109.8°E which put the center about 50 miles (80 km) south-southeast of Sanya, China.  Kajiki was moving toward the west at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 967 mb.

Typhoon Kajiki rapidly intensified to the equivalent of a Category 2 hurricane on the Saffir-Simpson Scale during Saturday night.  A circular eye with a diameter of 25 miles (40 km) formed at the center of Kajiki’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 Kajiki.  Storms near the center of Kajiki generated strong upper level divergence that pumped large quantities of mass away from the typhoon.  The removal of large amounts of mass caused the surface pressure to decrease rapidly.

The circulation around Typhoon Kajiki became more symmetrical when it rapidly intensified.  Winds to typhoon force extended out 30 miles (50 km) from the center of Kajiki’s circulation.  Winds to tropical storm force extended out 115 miles (185 km) from the center of Typhoon Kajiki.

The Hurricane Intensity Index (HII) for Typhoon Kajiki is 17.8.  The Hurricane Size Index (HSI) is 11.3 and the Hurricane Wind Intensity Size Index (HWISI) is 29.1.  Typhoon Kajiki is similar in size and intensity to Hurricane Sally when Sally hit South Alabama in 2020.

Typhoon Kajiki will move through an environment that is favorable for intensification during the next 24 hours.  Kajiki 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 northeasterly winds that will blow toward the top of Kajiki’s circulation.  The winds in the lower levels of the atmosphere will also blow from the northeast.  So, there will be little vertical wind shear.  Typhoon Kajiki will intensify during the next 24 hours as long as the center remains south of Hainan.  Kajiki could strengthen to the equivalent of a major hurricane.

Typhoom Kajiki will move around the southern side of a high pressure system over China.  The high pressure system will steer Kajiki toward the west during the next 24 hours.  On its anticipated track, the center of Typhoon Kajiki will continue to pass south of Hainan during the next 12 hours.  Kajiki will hit the coast of  northern Vietnam in 24 hours.

Typhoon Kajiki will continue bring strong winds and heavy rain to Hainan during the next 12 hours.  Heavy rain is likely to cause flash floods in some locations.

Typhoon Kajiki will also bring strong winds and heavy rain to northern Vietnam.  Heavy rain is likely to cause flash floods there as well.  Typhoon Kajiki could cause a storm surge of up to 10 feet (3 meters) along the coast of northern Vietnam.

Erin Transitions to Powerful Extratropical Cyclone

Former Hurricane Erin made a transition to a powerful extratropical cyclone over the Atlantic Ocean south of Nova Scotia on Friday.  At 5:00 p.m. EDT on Friday the center of former Hurricane Erin was located at latitude 40.0°N and longitude 59.7°W which put the center about 375 miles (605 km) south-southeast of Halifax, Nova Scotia.  Erin was moving toward the east-northeast at 33 m.p.h. (54 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 105 m.p.h. (165 km/h).  The minimum surface pressure was 957 mb.

Former Hurricane Erin made a transition to a large and powerful extratropical cyclone on Friday.  The structure of Erin’s circulation changed as part of its transition to an extratropical cyclone.  A warm front now extends east of the center of Erin’s circulation.  A cold front extends southwest of the center of former Hurricane Erin.

The size of the circulation around former Hurricane Erin increased as Erin made its transition to an extratropical cyclone.  Winds to hurricane force extend out 125 miles (200 km) from the center of circulation.  Winds to tropical storm force extend out 440 miles (705 km) from the center of former Hurricane Erin.

The Hurricane Intensity Index (HII) for former Hurricane Erin is 13.9.  The Hurricane Size Index (HSI) is 47.3 and the Hurricane Wind Intensity Size Index (HWISI) is 61.2.  Former Hurricane Erin is similar in size and intensity to Hurricane Sandy when Sandy hit the east coast of the U.S. in 2012.

The westerly winds in the middle latitudes will steer former Hurricane Erin quickly toward the east-northeast during the next few days.  On its anticipated track the powerful extratropical cyclone will be south of Iceland by early next week.

Hurricane Erin Passes South of Cape Cod

Hurricane Erin passed south of Cape Cod on Thursday afternoon.  At 5:00 p.m. EDT on Thursday the center of Hurricane Erin was located at latitude 36.4°N and longitude 69.1°W which put the center about 320 miles (520 km) south of Nantucket Island.   Erin was moving toward the northeast at 20 m.p.h. (32 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 952 mb.

A Tropical Storm Warning is in effect for the portion of the coast from Duck, North Carolina to Chincoteague, Virginia.

A Storm Surge Warning is in effect for the portion of the coast from Cape Lookout to Duck, North Carolina.

A Tropical Storm Warning is in effect for Bermuda.

Hurricane Erin started to weaken slowly as it moved over the Atlantic Ocean between Cape Cod and Bermuda on Thursday.  No eye was visible at the center of Erin’s circulation on satellite images.  Bands of showers and thunderstorms were revolving around the center of Hurricane Erin.  Storms near the center of Erin were still generating upper level divergence that pumped mass away from the hurricane.  The removal of mass in the upper levels of the atmosphere almost matched the inflow of mass in the lower levels.  There was slightly more mass flowing into the center of Erin’s circulation.  So, the surface pressure was slowly increasing.

The circulation around Hurricane Erin was very large.  Winds to hurricane force extend out 100 miles (160 km) from the center of Erin’s circulation.  Winds to tropical storm force extend out 320 miles (520 km) from the center of Hurricane Erin.

The Hurricane Intensity Index (HII) for Hurricane Erin is 16.5.  The Hurricane Size Index (HSI) is 36.9 and the Hurricane Wind Intensity Size Index (HWISI) is 53.4.  Hurricane Erin is similar in size and intensity to Hurricane Ike when Ike hit Texas in 2008.  Erin is not quite as strong as Ike was, but Hurricane Erin is bigger than Hurricane Ike was.

Hurricane Erin will move through an environment that will be unfavorable for intensification of a hurricane during the next 24 hours.  Erin will move over water where the Sea Surface Temperatures are near 26°C.  It will move under the eastern side of an upper level trough over the Northeast U.S. and the Great Lakes.  The upper level trough will produce southwesterly winds that will blow toward the top of Erin’s circulation.  Those winds will cause moderate vertical wind shear.  Hurricane Erin will weaken slowly during the next 24 hours.  Erin is likely to make a transition to a strong extratropical cyclone during the weekend.

The upper level trough over the Northeast U.S. and the Great Lakes will steer Hurricane Erin toward the east-northeast during the next 24 hours.  On its anticipated track, the center of Hurricane Erin will pass south of Nova Scotia on Friday.

The large circulation around Hurricane Erin will continue to produce large waves that will move toward the east coast of the U.S.  Erin could continue to cause a storm surge of up to four feet (one meter) along the Outer Banks of North Carolina on Thursday night.  Mandatory evacuations are in effect for Hatteras Island and Ocracoke Island.  Water has already washed over parts of Hatteras Island.  The large waves are likely to cause significant beach erosion.  Conditions along the Outer Banks should start to improve on Friday when Hurricane Erin moves farther away.

The large circulation around Hurricane Erin could also produce tropical storm force winds in Bermuda.

Hurricane Erin Moves Southeast of Cape Hatteras

Hurricane Erin moved southeast of Cape Hatteras on Wednesday night.  At 11:00 p.m. EDT on Wednesday the center of Hurricane Erin was located at latitude 32.8°N and longitude 73.1°W which put the center about 215 miles (345 km) southeast of Cape Hatteras, North Carolina.  Erin was moving toward the north-northeast at 16 m.p.h. (26 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 942 mb.

A Tropical Storm Warning is in effect for the portion of the coast from Beaufort Inlet, North Carolina to Chincoteague, Virginia.

A Storm Surge Warning is in effect for the portion of the coast from Cape Lookout to Duck, North Carolina.

A Tropical Storm Watch is in effect for Bermuda.

Concentric eyewalls formed again in Hurricane Erin on Wednesday.  The inner eyewall had a radius of 17 miles (28 km).  The outer eyewall had a radius of 75 miles (120 km).  The strongest winds were occurring in the outer eyewall.  Bands of showers and thunderstorms were revolving around the concentric eyewalls.  Storms near the center of Erin 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 on Wednesday.

The circulation around Hurricane Erin was very large.  Winds to hurricane force extend out 90 miles (145 km) from the center of Erin’s circulation.  Winds to tropical storm force extend out 265 miles (425 km) from the center of Hurricane Erin.

The Hurricane Intensity Index (HII) for Hurricane Erin is 19.2.  The Hurricane Size Index (HSI) is 33.0 and the Hurricane Wind Intensity Size Index (HWISI) is 52.2.  Hurricane Erin is similar in size and intensity to Hurricane Ike when Ike hit Texas in 2008.

Hurricane Erin will move through an environment that will become unfavorable for intensification during the next 24 hours.  Erin will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the eastern side of an upper level trough over the Northeast U.S. and the Great Lakes.  The upper level trough will produce southeasterly winds that will blow toward the top of Erin’s circulation.  Those winds will cause the vertical wind shear to increase on Thursday.  Hurricane Erin will start to weaken when the vertical wind shear increases.

The upper level trough over the Northeast U.S. and the Great Lakes will steer Hurricane Erin toward the northeast during the next 24 hours.  On its anticipated track, the center of Hurricane Erin will be move away from Cape Hatteras on Thursday.  Erin will pass far to the south of Long Island on Thursday.

The large circulation around Hurricane Erin will produce large waves that will move toward the east coast of the U.S.  Erin could cause a storm surge of up to four feet (one meter) along the Outer Banks of North Carolina.  Mandatory evacuations have been ordered for Hatteras Island and Ocracoke Island.  Water is already washing over parts of Hatteras Island.  The large waves are likely to cause significant beach erosion.  The large circulation around Hurricane Erin could also bring tropical storm force winds to the Outer Banks.  Conditions along the Outer Banks should start to improve on Friday when Hurricane Erin moves farther away.