Category Archives: Tropical Cyclones

Information about tropical cyclones

Hurricane Erin Prompts Watches for Outer Banks

The potential risks posed by Hurricane Erin prompted the issuance of a Tropical Storm Watch and a Storm Surge Watch for the North Carolina Outer Banks on Monday afternoon.  At 5:00 p.m. EDT on Monday the center of Hurricane Erin was located at latitude 24.0°N and longitude 71.3°W which put the center about 815 miles (1310 km) south-southeast of Cape Hatteras, North Carolina.  Erin was moving toward the northwest at 10 m.p.h. (16 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 937 mb.

A Tropical Storm Watch is in effect for the portion of the coast from Beaufort Inlet to Duck, North Carolina.  The Tropical Storm Watch includes Pamlico Sound.

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

A Tropical Storm Warning is in effect for the Turks and Caicos.  A Tropical Storm Warning is in effect for the Southeast Bahamas.

A Tropical Storm Watch is in effect for the Central Bahamas.

Hurricane Erin was maintaining its intensity on Monday afternoon.  A circular eye with a diameter of 45 miles (75 km) was at the center of Erin’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 core of Erin’s circulation.  Storms near the core of Erin were generating strong upper level divergence that was pumping mass away from the hurricane.  The removal of mass in the upper levels was approximately equal to the inflow of mass in the lower levels of the atmosphere/  The balance of outflow and inflow of mass caused the surface pressure to remain nearly constant.

An earlier eyewall replacement cycle increased the size of the circulation around Hurricane Erin.  Winds to hurricane force extended out 80 miles (130 km) from the center of Erin’s circulation.  Winds to tropical storm force extended out 230 miles (370 km) from the center of Hurricane Erin.

The Hurricane Intensity Index (HII) for Hurricane Erin is 28.3.  The Hurricane Size Index (HSI) is 24.4 and the Hurricane Wind Intensity Size Index (HWISI) is 52.7.  Hurricane Erin is similar in size and intensity to Hurricane Helene in 2024.

Hurricane Erin will move through an environment that will become less favorable for intensification during the next 24 hours.  Erin 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.  However, Erin will move into a region of drier air on Tuesday.  The drier air is likely to cause Hurricane Erin to start to weaken slowly.

Hurricane Erin will move around the southwestern side of a high pressure system over the Atlantic Ocean.  The high pressure system will steer Erin toward the northwest during the next 24 hours.  On its anticipated track, the center of Hurricane Storm Erin will pass of the Bahamas on Tuesday.

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.  The large waves could also cause significant beach erosion.  The large circulation around Hurricane Erin could also bring tropical storm force winds to the Outer Banks.

Bands in the western side of Hurricane Erin will continue to bring gusty winds and heavy rain to the Turks and Caicos and to the Southeast Bahamas until Erin moves farther away. The gusty winds and heavy rain could spread over the Central Bahamas on Tuesday.  Heavy rain could cause floods in some locations.

Hurricane Erin Strengthens

Hurricane Erin strengthened again on Monday morning as it moved north of the Turks and Caicos.  At 11:00 a.m. EDT on Monday the center of Hurricane Erin was located at latitude 23.1°N and longitude 70.8°W which put the center about 110 miles (175 km) north of Grand Turk Island.   Erin was moving toward the west-northwest at 10 m.p.h. (16 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 935 mb.

A Tropical Storm Warning is in effect for the Turks and Caicos.  A Tropical Storm Warning is in effect for the Southeast Bahamas.

A Tropical Storm Watch is in effect for the Central Bahamas.

Hurricane Erin began to strengthen again on Monday morning after it completed an eyewall replacement cycle.  A circular eye with a diameter of 37 miles (60 km) was at the center of Erin’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 core of Erin’s circulation. Storms near the core of Erin were generating strong upper level divergence that was pumping mass away from the hurricane.

The eyewall replacement cycle increased the size of the circulation around Hurricane Erin. Winds to hurricane force extended out 80 miles (130 km) from the center of Erin’s circulation. Winds to tropical storm force extended out 230 miles (370 km) from the center of Hurricane Erin.

The Hurricane Intensity Index (HII) for Hurricane Erin is 28.3.  The Hurricane Size Index (HSI) is 24.4 and the Hurricane Wind Intensity Size Index (HWISI) is 52.7.  Hurricane Erin is similar in size and intensity to Hurricane Helene in 2024.

Hurricane Erin will move through an environment that will be favorable for intensification during the next 12 hours. Erin 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.  Hurricane Erin could intensify during the next 12 hours.  Erin could move into a region of drier air on Tuesday.  The drier air would cause Hurricane Erin to start to weaken.

Hurricane Erin will move around the southwestern side of a high pressure system over the Atlantic Ocean.  The high pressure system will steer Erin toward the northwest during the next 24 hours.  On its anticipated track, the center of Hurricane Storm Erin will move east of the Bahamas on Tuesday.

Bands in the western side of Hurricane Erin is bring gusty winds and heavy rain to the Turks and Caicos and to the Southeast Bahamas.  The gusty winds and heavy rain could spread over the Central Bahamas on Tuesday.  Heavy rain could cause floods in some locations.

Hurricane Erin Moves North of Dominican Republic

Hurricane Erin moved north of the Dominican Republic on Sunday.  At 5:00 p.m. EDT on Sunday the center of Hurricane Erin was located at latitude 21.7°N and longitude 68.5°W which put the center about 200 miles (320 km) east of Grand Turk Island.  Erin was moving toward the west-northwest at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 946 mb.

A Tropical Storm Warning is in effect for the Turks and Caicos.  A Tropical Storm Warning is in effect for the Southeast Bahamas.

The inner end of a rainband wrapped around an existing eye and eyewall in the core of Hurricane Erin.  Concentric eyewalls formed.  Hurricane Erin weakened as the inflow became concentrated in the outer eyewall and the inner eyewall started to weaken.  The inner eyewall was still visible in satellite and radar images.  The presence of concentric eyewalls means that Hurricane Erin is still in an eyewall replacement cycle.

The outer eyewall in Hurricane Erin has a diameter of 45 miles (75 km).  Bands of showers and thunderstorms are revolving around the core of Erin’s circulation.  Storms near the core of Erin are generating strong upper level divergence that is pumping mass away from the hurricane.

The formation of concentric eyewalls increased the size of the circulation around Hurricane Erin.  Winds to hurricane force extended out 50 miles (80 km) from the center of Erin’s circulation.  Winds to tropical storm force extended out 200 miles (320 km) from the center of Hurricane Erin.

The Hurricane Intensity Index (HII) for Hurricane Erin is 23.6.  The Hurricane Size Index (HSI) is 14.6 and the Hurricane Wind Intensity Size Index (HWISI) is 38.2.  Hurricane Erin is similar in size and intensity to Hurricane Harvey in 2017.

Hurricane Erin will move through an environment that will be favorable for intensification during the next 24 hours.  Erin 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.  The eyewall replacement cycle is likely to prevent Hurricane Erin from intensifying quickly.  However, once the inner eyewall dissipates and the outer eyewall starts to contract, Erin could strengthen rapidly.

Hurricane Erin will move around the southwestern side of a high pressure system over the Atlantic Ocean.  The high pressure system will steer Erin toward the west-northwest during the next 24 hours. On its anticipated track, the center of Hurricane Storm Erin will pass northeast of the Turks and Caicos and the Southeast Bahamas on Monday.

Bands in the western side of Hurricane Erin could bring gusty winds and heavy rain to the Turks and Caicos and to the Southeast Bahamas.  Bands in the southern side of Erin’s circulation could drop heavy rain on parts of Haiti and the Dominican Republic.  Heavy rain could cause flash floods in some locations.

Hurricane Erin Rapidly Intensifies to Cat. 5

Hurricane Erin rapidly intensified to Category 5 on the Saffir-Simpson Scale on Saturday morning.   At 11:00 a.m. EDT on Saturday the center of Hurricane Erin was located at latitude 19.7°N and longitude 62.8°W which put the center about 105 miles (165 km) north of Anguilla.    Erin was moving toward the west at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 190 m.p.h. (305 km/h).  The minimum surface pressure was 917 mb.

Tropical Storm Watches are in effect for  St. Martin, St. Barthelemy, and Sint Maarten.

Hurricane Erin rapidly intensified to a Category 5 hurricane on the Saffir-Simpson Scale on Saturday morning.  A small circular eye with a diameter of 6 miles (10 km) was at the center of Erin’s circulation.  A ring of thunderstorms surrounded the eye and the strongest winds winds occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Hurricane Erin.  Storms near the center of Erin generated strong upper level divergence that pumped large quantities of mass away from the hurricane.  The removal of large amounts of mass caused the surface pressure to decrease rapidly.

The circulation around Hurricane Erin is small.  Winds to hurricane force extend out 30 miles (50 km) from the center of Erin’s circulation.  Winds to tropical storm force extend out 140 miles (220 km) in the northern side of Hurricane Erin.  Winds to tropical storm force extend out 60 miles in the southern half of Erin’s circulation.

The Hurricane Intensity Index (HII) is 35.0. The Hurricane Size Index (HSI) is 9.2 and the Hurricane Wind Intensity Size Index (HWISI) is 44.2. Hurricane Erin is similar in intensity to Hurricane Michael in 2018.  Erin is smaller than Michael was.

Hurricane Erin will move through an environment that will be favorable for intensification during the next 24 hours.  Erin 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.  Hurricane Erin is likely to continue to intensify during the next few hours.  However, it is likely that the inner end of a rainband will wrap around the existing eye and eyewall.  That would create concentric eyewalls.  It would also start an eyewall replacement cycle.  An eyewall replacement cycle would cause Hurricane Erin to weaken, at least temporarily.

Hurricane Erin will move around the southern side of a high pressure system over the Atlantic Ocean.  The high pressure system will steer Erin toward the west-northwest during the next 24 hours.  On its anticipated track, the center of Hurricane Storm Erin will pass north of the Puerto Rico on Saturday night.

Bands in the southern side of Hurricane Erin are likely to bring gusty winds and locally heavy rain to the Northern Leeward Islands and to the Virgin Islands.  Heavy rain could cause flash floods in some locations.  Bands feeding into the southern side of Hurricane Erin could also drop heavy rain on Puerto Rico.

A Flood Watch is in effect for Puerto Rico.

Hurricane Erin Rapidly Intensifies to Cat. 4

Hurricane Erin rapidly intensified to Category 4 on the Saffir-Simpson Scale on Saturday morning.  At 8:00 a.m. EDT on Saturday the center of Hurricane Erin was located at latitude 19.6°N and longitude 62.0°W which put the center about 120 miles (195 km) northeast of Anguilla.   Erin was moving toward the west-northwest at 20 m.p.h. (32 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 935 mb.

Tropical Storm Watches are in effect for  St. Martin, St. Barthelemy, and Sint Maarten.

Hurricane Erin rapidly intensified to a Category 4 hurricane on the Saffir-Simpson Scale early on Saturday morning.  A circular eye with a diameter of 12 miles (19 km) was at the center of Erin’s circulation.  A ring of thunderstorms surrounded the eye and the strongest winds winds occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Hurricane Erin.  Storms near the center of Erin generated strong upper level divergence that pumped large quantities of mass away from the hurricane.  The removal of large amounts of mass caused the surface pressure to decrease rapidly.

The circulation around Hurricane Erin is small.  Winds to hurricane force extend out 30 miles (50 km) from the center of Erin’s circulation.  Winds to tropical storm force extend out 130 miles (210 km) in the northern side of Hurricane Erin.  Winds to tropical storm force extend out 60 miles in the southern half of Erin’s circulation.

The Hurricane Intensity Index (HII) is 29.9.  The Hurricane Size Index (HSI) is 8.4 and the Hurricane Wind Intensity Size Index (HWISI) is 38.3.  Hurricane Erin is similar in size and intensity to Hurricane Charley in 2004.

Hurricane Erin will move through an environment that will be very favorable for intensification during the next 24 hours.  Erin 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.  Hurricane Erin will intensity during the next 24 hours.  Erin could strengthen to Category 5 on the Saffir-Simpson Scale.

Hurricane Erin will move around the southern side of a high pressure system over the Atlantic Ocean.  The high pressure system will steer Erin toward the west-northwest during the next 24 hours.  On its anticipated track, the center of Hurricane Storm Erin will pass north of the Puerto Rico on Sunday.

Bands in the southern side of Hurricane Erin are likely to bring gusty winds and locally heavy rain to the Northern Leeward Islands.  Heavy rain could cause flash floods in some locations.  Bands feeding into the southern side of Hurricane Erin could also drop heavy rain on Puerto Rico.

A Flood Watch is in effect for Puerto Rico.

Erin Strengthens to a Hurricane

Former Tropical Storm Erin strengthened to a hurricane east of the Northern Leeward Islands on Friday.  At 11:00 a.m. EDT on Friday the center of Hurricane Erin was located at latitude 18.2°N and longitude 56.1°W which put the center about 460 miles (740 km) east of the Northern Leeward Islands.  Erin was moving toward the west-northwest at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 996 mb.

Tropical Storm Watches are in effect for Anguilla, Barbuda, St. Martin, St. Barthelemy, Saba, St. Eustatius, and Sint Maarten.

Former Tropical Storm Erin strengthened to a hurricane east of the Northern Leeward Islands on Friday.  The inner end of a rainband wrapped around the center of Erin’s circulation.  A small eye with a diameter of 12 miles (19 km) formed at the center of Hurricane Erin.  Bands of showers and thunderstorms were revolving around the center of Erin’s circulation.  Storms near the center generated upper level divergence that was pumping mass away from the hurricane.

The strongest winds were occurring in the northeastern part of Hurricane Erin.  Winds to hurricane force extended out 25 miles (40 km) in the northeastern quadrant of Erin’s circulation.  Winds to tropical storm force extended out 115 miles (185 km) from the center of Hurricane Erin.

Hurricane Erin will move through an environment favorable 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 southern part of an upper level ridge over the eastern Atlantic Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Erin’s circulation. The winds in the lower levels of the atmosphere will also blow from the east, but winds will be stronger in the upper troposphere.  So, there will be some vertical wind shear.  The vertical wind shear will slightly inhibit intensification, but the shear will not be enough to prevent intensification. Hurricane Erin will intensity during the next 24 hours.  Erin is likely to strengthen to a major hurricane during the weekend.

Hurricane Erin will move around the southern side of a high pressure system over the Atlantic Ocean.  The high pressure system will steer Erin toward the west-northwest during the next 24 hours.  On its anticipated track, the center of Hurricane Storm Erin will pass north of the Northern Leeward Islands on Saturday.

Bands in the southern side of Hurricane Erin are likely to bring gusty winds and locally heavy rain to the Northern Leeward Islands.  Heavy rain could cause flash floods in some locations.  Bands feeding into the southern side of Hurricane Erin could also drop heavy rain on Puerto Rico.

A Flood Watch is in effect for Puerto Rico.

Erin Prompts Tropical Storm Watches for Northern Leeward Islands

The potential risk posed by Tropical Storm Erin prompted the issuance of Tropical Storm Watches for the Northern Leeward Islands on Thursday afternoon.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Erin was located at latitude 16.7°N and longitude 51.2°W which put the center about 790 miles (1270 km) east of the Northern Leeward Islands.  Erin was moving toward the west at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 998 mb.

Tropical Storm Watches are in effect for Anguilla, Barbuda, St. Martin, St. Barthelemy, Saba, St. Eustatius, and Sint Maarten.

Tropical Storm Erin continued to strengthen gradually on Thursday.  Even though Tropical Storm Erin was strengthening, the distribution of thunderstorms was asymmetrical.  Thunderstorms were occurring mainly in bands in the western side of Erin’s circulation.  Bands in the eastern side of Tropical Storm Erin consisted primarily of showers and lower clouds.  Storms near the center of Erin generated upper level divergence that pumped mass away to the west of the tropical storm.  The removal of mass caused the surface pressure to decrease slowly.

The circulation around Tropical Storm Erin is small,  Winds to tropical storm force extend out 60 miles (95 km) from the center of Erin’s circulation.

Tropical Storm Erin will move through an environment mostly favorable 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 southern part of an upper level ridge over the eastern Atlantic Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Erin’s circulation.  The winds in the lower levels of the atmosphere will also blow from the east, but winds will be stronger in the upper troposphere.  So, there will be some vertical wind shear.  The vertical wind shear will inhibit intensification, but the shear will not be enough to prevent intensification.  Tropical Storm Erin will intensity during the next 24 hours.  Erin is likely to strengthen to a hurricane on Friday.

Tropical Storm Erin will move around the southern side of a high pressure system over the eastern Atlantic Ocean.  The high pressure system will steer Erin toward the west during the next 24 hours.  On its anticipated track, Tropical Storm Erin will move toward the Northern Leeward Islands.  Erin could approach the Northern Leeward Islands on Friday night.

Tropical Storm Erin is likely to bring gusty winds and locally heavy rain to the Northern Leeward Islands.  Heavy rain could cause flash floods in some locations.

Tropical Storm Erin Strengthens a Little

Tropical Storm Erin strengthened a little on Wednesday as it moved over the Atlantic Ocean east of the Northern Leeward Islands.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Erin was located at latitude 16.3°N and longitude 46.6°W which put the center about 1095 miles (17635 km) east of the Northern Leeward Islands.  Erin was moving toward the west at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 1002 mb.

Tropical Storm Erin strengthened a little on Wednesday.  More thunderstorms formed near the center of Erin’s circulation.  Thunderstorms were also occurring in bands in the western side of Tropical Storm Erin.  Bands in the eastern side of Erin’s circulation consisted primarily of showers and lower clouds.  Storms near the center of Erin generated upper level divergence that pumped mass away to the west of the tropical storm.

The strongest winds were occurring in the northern side of Tropical Storm Erin.  Winds to tropical storm force extended out 60 miles (95 km) in the northern half of Erin’s circulation.  The winds in the southern side of Tropical Storm Erin were blowing at less than tropical storm force.

Tropical Storm Erin will move through an environment somewhat favorable for intensification during the next 24 hours.  Erin will move over water where the Sea Surface Temperatures are near 27°C.  It will move under the southern part of an upper level ridge over the eastern Atlantic Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Erin’s circulation.  The winds in the lower levels of the atmosphere will also blow from the east, but winds will be stronger in the upper troposphere.  So, there will be some vertical wind shear.  The vertical wind shear will inhibit intensification, but the shear will not be enough to prevent intensification.  Tropical Storm Erin will intensity during the next 24 hours.  Erin will move over warmer water on Friday.  Erin is likely to strengthen to a hurricane on by Friday evening.

Tropical Storm Erin will move around the southern side of a high pressure system over the eastern Atlantic Ocean.  The high pressure system will steer Erin toward the west during the next 24 hours.  On its anticipated track, Tropical Storm Erin will move toward the Northern Leeward Islands.  Erin could approach the Northern Leeward Islands on Friday night.

Typhoon Podul Nears Taiwan

Typhoon Podul was nearing southern Taiwan on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Typhoon Podul was located at latitude 22.3°N and longitude 122.6°E which put the center about 100 miles (160 km) east-southeast of Taitung, Taiwan.  Podul was moving toward the west-northwest at 17 m.p.h. (28 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 970 mb.

Typhoon Podul was intensifying as it approached southern Taiwan on Tuesday.  A circular eye with a diameter of 30 miles (48 km) was at the center of Podul’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 Podul.  Storms near the center generated upper level divergence that pumped mass away to the south and west of the typhoon.  The removal of mass caused the surface pressure to decrease.

The size of the circulation around Typhoon Podul increased as Podul intensified on Tuesday.  Winds to typhoon force extended out 60 miles (95 km) from the center of Podul’s circulation.  Winds to tropical storm force extended out 150 miles (240 km) from the center of Typhoon Podul.

The Hurricane Intensity Index (HII) for Typhoon Podul is 16.5.  The Hurricane Size Index (HSI) is 16.7 and the Hurricane Wind Intensity Size Index (HWISI) is 33.2.  Typhoon Podul is similar in intensity to Hurricane Idalia when Idalia hit Florida in 2023.  Typhoon Podul is much larger than Idalia was.

Typhoon Podul will move through an environment that will be mostly favorable for intensification during the next few hours.  Podul will move over water where the Sea Surface Temperatures are near 29°C.  An upper level ridge over eastern China will produce northeasterly winds that will blow toward the top of Podul’s circulation.  Those winds will cause moderate vertical wind shear. The vertical wind shear will inhibit intensification, but the shear may not be enough to prevent intensification.  Typhoon Podul could continue to intensify during the next few hours.

Typhoon Podul will move around the southern side of a high pressure system that is south of Japan.  The high pressure system will steer Podul toward the west-northwest during the next 24 hours.  On its anticipated track, Typhoon Podul will make landfall in southeastern Taiwan in a few hours.

Typhoon Podul will bring strong gusty winds and heavy rain to Taiwan.  The heaviest rain will fall in southern Taiwan and on the eastern slopes of mountains in eastern Taiwan.  Heavy rain is likely to cause flash floods in some locations.

The Taiwan Central Weather Administration has issued a Land Typhoon Warning for much of Taiwan.  A Sea Typhoon Warning is in effect for much of the waters surrounding Taiwan.

The Taiwan Central Weather Administration has issued an Extremely Heavy Rain Advisory for much of southern and eastern Taiwan.

Typhoon Podul could also cause a storm surge of up to 10 feet (3 meters) along parts of the east coast of Taiwan.

Henriette Weakens Back to a Tropical Storm

Former Hurricane Henriette weakened back to a tropical storm over the Central Pacific Ocean north of Hawaii on Tuesday.  At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Henriette was located at latitude 32.8°N and longitude 161.6°W which put the center about 825 miles (1330 km) north-northwest of Honolulu, Hawaii.  Henriette was moving toward the northwest at 16 m.p.h. (26 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 994 mb.

Former Hurricane Henriette weakened back to a tropical storm over the Central Pacific Ocean north of Hawaii on Tuesday.  Henriette moved into a region of drier air that is northwest of Hawaii.  The drier air was pulled around the southern side of Tropical Storm Henriette.  The drier air affect the structure of Henriette.

Thunderstorms were still occurring near the center of Tropical Storm Henriette.  Thunderstorms were also still occurring in bands in the eastern and northern sides of Henriette’s circulation.  Bands in the southern and western sides of Tropical Storm Henriette consisted primarily of showers and lower clouds.

The circulation around Tropical Storm Henriette was small.  Winds to tropical storm force extended out 80 miles (130 km) from the center of Henriette’s circulation.

Tropical Storm Henriette will move through an environment that will become more unfavorable for intensification during the next 24 hours.  Henriette will move over water where the Sea Surface Temperatures are near 26°C.  It will move under the eastern side of an upper level low that is northwest of Hawaii.  The upper level low will produce southerly winds that will blow toward the top of Henriette’s circulation.  Those winds will cause the vertical wind shear to increase.  In addition, Henriette will continue to move through the region of drier air northwest of Hawaii.  More vertical wind shear and the effects of the drier will cause Tropical Storm Henriette to continue to weaken during the next 24 hours.

Tropical Storm Henriette will move around the southwestern part of a high pressure system over the central North Pacific Ocean.  The high pressure system will steer Henriette toward the northwest during the next 24 hours.  On its anticipated track, Tropical Storm Henriette will continue to move farther away from Hawaii.