Tropical Storm Hanna Forms over Central Atlantic

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Tropical Storm Hanna formed over the Central North Atlantic Ocean west of the Azores on Monday.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Hanna was located at latitude 36.5°N and longitude 47.8°W which put the center about 1195 miles (1920 km) west of the Azores.  Hanna was moving toward the east-southeast at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1006 mb.

A low pressure system over the Central North Atlantic Ocean strengthened on Monday and the U.S. National Hurricane Center designated the system as Tropical Storm Hanna.

Tropical Storm Hanna was moving under the southern extent of the upper level westerly winds in the middle latitudes.  Those upper level winds were causing moderate to strong vertical wind shear.  The vertical wind shear caused the distribution of thunderstorms in Tropical Storm Hanna to be asymmetrical.  Thunderstorms were occurring in bands in the eastern side of Hanna’s circulation.  Bands in the western side of Tropical Storm Hanna consisted primarily of showers and lower clouds.

The distribution of wind speeds in Tropical Storm Hanna was also asymmetrical.  Winds to tropical storm force extended out 90 miles (145 km) in the eastern side of Hanna’s circulation.  The winds in the western side of Tropical Storm Hanna were blowing at less than tropical storm force.

Tropical Storm Hanna will move through an environment that will be only marginally favorable for intensification during the next 24 hours.  Hanna will move over water where the Sea Surface Temperatures are near 27°C.  It will continue to move under the upper level westerly winds in the middle latitudes.  Those upper level winds will continue to cause moderate to strong vertical wind shear.  Tropical Storm Hanna could intensify a little on Tuesday in spite of the vertical wind shear.  However, the vertical wind shear is more likely to cause Hanna to weaken.

Tropical Storm Hanna will move around the northern side of a high pressure system that is over the North Central Atlantic Ocean.  The high pressure system will steer Hanna toward the east-southeast during the next 24 hours.  On its anticipated track, Tropical Storm Hanna will remain far to the west of the Azores.

Elsewhere over the Atlantic Ocean, Tropical Depression Fay was spinning south of Tropical Storm Hanna.  At 5:00 p.m. EDT on Monday the center of Tropical Depression Fay was located at latitude 26.6°N and longitude 45.3°W which put the center about 1325 miles (2130 km) west-southwest of the Azores.  Fay was moving toward the southwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1011 mb.

Hurricane Polo Nears Southern Baja California

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Hurricane Polo moved nearer to the coast of southern Baja California on Sunday evening.

At 11:00 p.m. EDT on Sunday the center of Hurricane Polo was located at latitude 22.8°N and longitude 114.0°W which put the center about 175 miles (280 km) southwest of Cabo San Lazaro, Mexico.  Polo was moving toward the north at 12 m.p.h. (19 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 951 mb.

A Hurricane Warning is in effect for the portion of the west coast of Baja California from Punta Abreojos to Santa Fe, Mexico.

A Hurricane Warning is in effect for the portion of the east coast of Baja California from  Loreto to Santa Rosalia, Mexico.

A Hurricane Warning is in effect for the portion of the coast from Guaymas to Huatabampito, Mexico.

A Tropical Storm Warning and a Hurricane Watch  is in effect for the portion of the coast from Punta Eugenia to Punta Abreojos, Mexico.

A Tropical Storm Warning and a Hurricane Watch is in effect for the portion of the coast from ; Loreto to San Evaristo, Mexico.

A Tropical Storm Warning and a Hurricane Watch is in effect for the portion of the coast from Santa Rosalia to Bahia San Juan Bautista, Mexico

A Tropical Storm Warning and a Hurricane Watch is in effect for the portion of the coast from Guaymas to Bahia Kino, Mexico.

A Tropical Storm Warning and a Hurricane Watch is in effect for the portion of the coast from Huatabampito to Topolobampo, Mexico.

Hurricane Polo was still a major hurricane on Sunday evening.  A circular eye with a diameter of 17 miles (28 km) was present at the center of Polo’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 Polo.  Storms near the center of Polo generated upper level divergence that pumped mass away from the hurricane.  The removal of mass in the upper levels was nearly equal to the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure did not change much on Sunday.

The distribution of wind speeds in Hurricane Polo was fairly symmetrical.  Winds to hurricane force extended out 45 miles (75 km) from the center of Polo’s circulation.  Winds to tropical storm force extended out 105 miles (165 km) from the center of Hurricane Polo.

The Hurricane Intensify Index (HII) for Hurricane Polo is 23.4. The Hurricane Size Index (HSI) is 14.6 and the Hurricane Wind Intensity Size Index (HWISI) is 38.0.  Hurricane Polo is similar in size and intensity to Hurricane Milton when Milton hit Florida in 2024.

Hurricane Polo will move through an environment that will be unfavorable for intensification during the next 24 hours.  Polo will move over water where the Sea Surface Temperatures are near 28°C.  However, Polo will move under the southern part of an upper level trough that is near the West Coast of the U.S.  The upper level trough will produce southwesterly winds that will blow toward the top of Polo’s circulation.  Those winds will cause the vertical wind shear to increase on Monday.  Hurricane Polo will weaken during the next 24 hours because of more vertical wind shear.

The upper level trough near the West Coast of the U.S. will pull Hurricane Polo toward the northeast during the next 24 hours.  On its anticipated track, the center of Hurricane Polo will make landfall on the coast of southwest Baja California north of Cabo San Lazaro on Monday afternoon.

Hurricane Polo will bring strong winds and heavy rain to southern Baja California. Heavy rain is likely to cause flash floods in some locations.

Elsewhere over the Eastern North Pacific Ocean, Tropical Storm Rachel formed south of Mexico.

At 11:00 p.m. EDT on Sunday the center of Tropical Storm Rachel was located at latitude 12.9°N and longitude 99.8°W which put the center about 275 miles (445 km) south-southwest of Acapulco, Mexico.  Rachel was moving toward the west at 7 m.p.h. (11 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 1003 mb.

A Tropical Storm Watch is in effect for the portion of the coast from Punta San Telmo to Playa, Perula, Mexico.

Nolo Strengthens to a Major Hurricane

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Hurricane Nolo strengthened to a major hurricane as it moved over the Central North Pacific Ocean south of Hawaii on Sunday.

At 5:00 p.m. EDT on Sunday the center of Hurricane Nolo was located at latitude 16.2°N and longitude 159.3°W which put the center about 365 miles (585 km) south-southwest of Honolulu, Hawaii.  Nolo was moving toward the west at 12 m.p.h. )19 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 135 m.p.h. (215 km/h).  The minimum surface pressure was 966 mb.

A Hurricane Watch is in effect for the Papahanaumokuakea Marine National Monument from Nihoa to French Frigate Shoals.

Hurricane Nolo intensified to a major hurricane on Sunday.  A circular eye with a diameter of 35 miles was at the center of Nolo’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 Nolo.  Storms near the center of Nolo generated upper level divergence that pumped mass away from the hurricane.  The removal of mass caused the surface pressure to decrease.

The distribution of wind speeds around Hurricane Nolo was fairly symmetrical.  Winds to hurricane force extended out 35 miles (55 km) from the center of Nolo’s circulation.  Winds to tropical storm force extended out 150 miles (240 km) from the center of Hurricane Nolo.

The Hurricane Intensity Index (HII) for Hurricane Nolo is 20.6.  The Hurricane Size Index (HSI) is 14.0 and the Hurricane Wind Intensity Size Index (HWISI) is 34.6.  Hurricane Nolo is similar in size and intensity to Hurricane Delta when Delta hit Southwest Louisiana in 2020.

Hurricane Nolo will move through an environment that will be favorable for intensification during the next 24 hours.  Nolo will move over water where the Sea Surface Temperatures are near 28°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Hurricane Nolo will intensify during the next 24 hours.

Hurricane Nolo will move around the southwestern part of a high pressure system that is over the Central North Pacific Ocean.  The high pressure system will steer Nolo toward the northwest during the next 24 hours.  On its anticipated track, Hurricane Nolo will stay southwest of Hawaii on Monday.

 

Typhoon Surigae Intensifies to Equivalent of Major Hurricane

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Typhoon Surigae intensified to the equivalent of a major hurricane on Saturday night as it moved over the Western North Pacific Ocean southeast of Okinawa.  At 5:00 a.m. EDT on Sunday the center of Typhoon Surigae was located at latitude 25.7°N and longitude 128.6°E which put the center about 80 miles (130 km) southeast of Okinawa.  Surigae 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 952 mb.

Typhoon Surigae intensified to the equivalent of a major hurricane on Saturday night.  A circular eye with a diameter of 20 miles (32 km) was at the center of Surigae’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 Surigae.  Storms near the center of Surigae generated upper level divergence that pumped mass away from the typhoon.  The removal of mass caused the surface pressure to decrease.

The distribution of wind speed around Typhoon Surigae became more symmetrical when Surigae intensified.  Winds to typhoon force extended out 25 miles (40 km) from the center of Surigae’s circulation.  Winds to tropical storm force extended out 90 miles (145 km) from the center of Typhoon Surigae.

The Hurricane Intensity Index (HII) for Typhoon Surigae is 22.1.  The Hurricane Size Index (HSI) is 9.2 and the Hurricane Wind Intensity Size Index (HWISI) is 31.3.  Typhoon Surigae is similar in size and intensity to Hurricane Zeta when Zeta hit Louisiana in 2020.

Typhoon Surigae will move through an environment that will be somewhat favorable for intensification during the next 24 hours.  Surigae will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the southern part of an upper level trough that is northwest of Japan.  The upper level trough will produce southwesterly winds that will blow toward the top of Surigae’s circulation.  Those winds will cause some vertical wind shear, but the wind shear may not be enough to prevent intensification.  Typhoon Surigae could continue to intensify Sunday.  The vertical wind shear will increase on Monday when Surigae moves closer to the upper level westerly winds in the middle latitudes.  Typhoon Surigae will start to weaken when the vertical wind shear increases.

Typhoon Surigae will move around the western end of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer Surigae toward the northeast during the next 24 hours.  On its anticipated track, the center of Typhoon Surigae will move away Okinawa on Sunday.

Typhoon Surigae will continue to bring strong winds and locally heavy rain to the Ryukyu Islands including Okinawa on Sunday.  Heavy rain is likely to cause flash floods in some locations.  The strong winds and rain will end gradually as Surigae moves away from the Ryukyu Islands.

Polo Prompts Hurricane Warning for Baja California

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A risk posed by Hurricane Polo prompted the government of Mexico to issue a Hurricane Warning for a portion of the west coast of Baja California on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Hurricane Polo was located at latitude 19.3°N and longitude 113.1°W which put the center about 325 miles (520 km) southwest of Cabo San Lucas, Mexico.  Polo was moving toward the northwest 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 140 m.p.h. (225 km/h).  The minimum surface pressure was 949 mb.

A Hurricane Warning is in effect for the portion of the coast from Punta Abreojos to Sante Fe, Mexico.

A Hurricane Watch is in effect for the portion of the coast from Punta Eugenia to Punta Abreojos, Mexico.

A Hurricane Watch is in effect for the portion of the coast from Bahia San Juan Bautista to San Evaristo, Mexico.

A Tropical Storm Warning is in effect for the portion of the coast from Punta Eugenia to Punta Abreojos, Mexico.

Hurricane Polo weakened steadily on Saturday, but Polo was still a major hurricane on Saturday evening.  A circular eye was still present at the center of Polo’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 Polo.  Storms near the center of Polo generated upper level divergence that pumped mass away from the hurricane.  The removal of more mass in the upper levels was less than the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure increased on Saturday.

The size of the circulation around Hurricane Polo increased on Saturday.  Winds to hurricane force extended out 40 miles (65 km) from the center of Polo’s circulation.  Winds to tropical storm force extended out 160 miles (260 km) from the center of Hurricane Polo.

The Hurricane Intensify Index (HII) for Hurricane Polo is 22.1. The Hurricane Size Index (HSI) is 14.9 and the Hurricane Wind Intensity Size Index (HWISI) is 37.0.  Hurricane Polo is similar in size and intensity to Hurricane Milton when Milton hit Florida in 2024.

Hurricane Polo will move through an environment that will be unfavorable for intensification during the next 24 hours.  Polo will move over water where the Sea Surface Temperatures are near 28°C.  However, Polo will move under the southeastern part of an upper level trough that is near the West Coast of the U.S.  The upper level trough will produce southwesterly winds that will blow toward the top of Polo’s circulation.  Those winds will cause the vertical wind shear to increase.  Hurricane Polo will continue to weaken on Sunday because of more vertical wind shear.

Hurricane Polo will move around the western part of a high pressure system that is over Mexico.  The high pressure system will steer Polo toward the north during the next 24 hours.  The upper level trough that is near the West Coast of the U.S. will steer Polo toward the northeast on Monday.  Polo will reach southern Baja California on Monday.

Hurricane Polo will bring strong winds and heavy rain to southern Baja California.  Heavy rain is likely to cause flash floods in some locations.

Elsewhere over the Eastern North Pacific Ocean, the upper level trough near the West Coast of the U.S. caused Hurricane Odalys to weaken on Saturday.  At 11:00 p.m. EDT on Saturday the center of Hurricane Odalys was located at latitude 21.1°N and longitude 123.6°W which put the center about 885 miles (1425 km) west of the the southern tip of Baja California.  Odalys was moving toward the north at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 979 mb.

Hurricane Nolo Stalls South of Hawaii

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Hurricane Nolo stalled south of Hawaii early on Saturday.  At 8:00 a.m. EDT on Saturday the center of Hurricane Nolo was located at latitude 16.9°N and longitude 155.3°W which put the center about 145 miles (235 km) south of South Point, Hawaii.  Nolo was stationary.   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 975 mb.

A Hurricane Watch is in effect for Hawaii County.

A Tropical Storm Warning is in effect for Hawaii County.

A Tropical Storm Watch is in effect for Maui County including Maui, Lanai, Molokai, and Kahoolawe.

Hurricane Nolo was a Category 2 hurricane on the Saffir-Simpson Scale on Tuesday morning.  A circular eye with a diameter of 23 miles (37 km) was at the center of Nolo’s circulation.  They eye was surrounded by a broken 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 Nolo.  Storms near the center of Nolo generated upper level divergence that pumped mass away from the hurricane.  The removal of mass caused the surface pressure to decrease.

Winds to hurricane force extended out 45 miles (75 km) from the center of Hurricane Nolo. Winds to tropical storm force extended out 140 miles (225 km) from the center of Nolo’s circulation.

The Hurricane Intensity Index (HII) for Hurricane Nolo is 17.8.  The Hurricane Size Index (HSI) is 16.1 and the Hurricane Wind Intensity Size Index (HWISI) is 33.9.

Hurricane Nolo will move through an environment that will be somewhat favorable for intensification during the next 24 hours.  Nolo will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the southeastern part 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 Nolo’s circulation.  Those winds will cause some vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear may not be enough to prevent intensification.  Hurricane Nolo could intensify gradually during the next 24 hours.  Nolo could strengthen to a major hurricane during the weekend.

A high pressure system north of Hawaii is forecast to strengthen on Saturday.  When the high pressure system strengthens, it will start to steer Hurricane Nolo toward the west.  On its anticipated track, the center of Hurricane Nolo will remain south of Hawaii during the weekend.

The circulation around the northern side of Hurricane Nolo will produce easterly winds in parts of the Big Island of Hawaii and on Maui.  Heavy rain could fall where those winds blow up the slopes of hills and mountains.  Heavy could cause flash floods in some locations.

Flood Watches are in effect for the Big Island of Hawaii, Maui, Lanai, Molokai, and Kahoolawe.

Surigae Strengthens to Typhoon South of Okinawa

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Former Tropical Storm Surigae strengthened to a typhoon on Friday night as it moved south of Okinawa.  At 5:00 a.m. EDT on Saturday the center of Typhoon Surigae was located at latitude 23.2°N and longitude 126,8°E which put the center about 255 miles (415 km) south-southwest of Okinawa.  Surigae was moving toward the north-northwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 95 m.p.h. (150 km/h).  The minimum surface pressure was 981 mb.

Former Tropical Storm Surigae strengthened to a typhoon on Friday night.  The inner end of a rainband wrapped around the western and southern sides of the center of Typhoon Surigae.  Other bands of showers and thunderstorms were revolving around the center of Surigae’s circulation.  Storms near the center of Surigae generated upper level divergence that pumped mass away from the typhoon.  The removal of mass caused the surface pressure to decrease.

The strongest winds were occurring in the southern side of the center of Typhoon Surigae.  Winds to typhoon force extended out 25 miles (40 km) in the southern side of Surigae’s circulation.  Winds to tropical storm force extended out 90 miles from the center of Typhoon Surigae.

Typhoon Surigae will move through an environment that will be favorable for intensification during the next 24 hours.  Surigae will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the western part of an upper level ridge that is south of Japan.  The upper level ridge will produce southerly winds that will blow toward the top of Surigae’s circulation.  Those winds will cause some vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  Typhoon Surigae will intensify during the next 24 hours.

Typhoon Surigae will move around the western end of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer Surigae toward the north during the next 24 hours.  On its anticipated track, the center of Typhoon Surigae will be just south of Okinawa in 24 hours.

Typhoon Surigae will bring strong winds and locally heavy rain to the Ryukyu Islands including Okinawa.  Heavy rain is likely to cause flash floods in some locations.

Tropical Storm Gonzalo Buffets Cabo Verde Islands

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Tropical Storm Gonzalo buffeted the Cabo Verde Islands with gusty winds and locally heavy rain on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Gonzalo was located at latitude 16.2°N and longitude 22.7°W which put the center about 35 miles (55 km) south-southeast of Sal, Cabo Verde.   Gonzalo was moving toward the north at 12 m.p.h. (19 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 1000 mb.

A Tropical Storm Warning is in effect for all of the Cabo Verde Islands.

Even though Tropical Storm Gonzalo strengthened on Friday, the distribution of thunderstorms was still asymmetrical.  Thunderstorms were occurring in bands in the northeastern part of Gonzalo’s circulation.  Bands in the other parts of Tropical Storm Gonzalo consisted primarily of showers and lower clouds.  Storms near the center of Gonzalo generated upper level divergence that pumped mass away to the east of the tropical storm.  The removal of mass caused the surface pressure to decrease a little on Friday.

The distribution of winds speeds in Tropical Storm Gonzalo was also asymmetrical.  Winds to tropical storm force extended out 200 miles (320 km) in the northern side of Gonzalo’s circulation.  Winds to tropical storm force only extended out 45 miles (75 km) in the southern side of Tropical Storm Gonzalo.

Tropical Storm Gonzalo will move through an environment that will be unfavorable for intensification during the next 24 hours.  Gonzalo will move over water where the Sea Surface Temperatures are near 27°C.  It will move under the eastern side of an upper level trough that is west of Africa.  The upper level trough will produce southwesterly winds that will blow toward the top of Gonzalo’s circulation.  Those winds will cause strong vertical wind shear.   The strong vertical wind shear will likely cause Tropical Storm Gonzalo to weaken on Saturday.

The upper level trough that is west of Africa will pull Tropical Storm Gonzalo toward the north during the next 24 hours.  On its anticipated track, Tropical Storm Gonzalo will start to move away from the Cabo Verde Islands on Saturday.

Tropical Storm Gonzalo will continue to bring strong winds and heavy rain to the Cabo Verde Islands on Saturday.  Heavy rain is likely to cause flash floods in some locations.

Elsewhere over the Atlantic Ocean, Tropical Storm Fay continued to spin over the central North Atlantic.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Fay was located at latitude 29.8°N and longitude 43.0°W which put the center about 1075 miles (1730 km) west-southwest of the Azores.  Fay was moving toward the west-southwest at 5 m.p.h. (8 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 1004 mb.

Hurricane Polo Strengthens Back to Cat. 5 Again

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Hurricane Polo strengthened back to Category 5 on the Saffir-Simpson Scale again early on Friday as it moved over the Eastern North Pacific Ocean south of Baja California.

At 9:00 a.m. EDT on Friday the center of Hurricane Polo was located at latitude 17.1°N and longitude 108.2°W which put the center about 415 miles (665 km) south-southeast of Cabo San Lucas, Mexico.  Polo was moving toward the west at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 180 m.p.h. (290 km/h) and there were wind gusts to 215 m.p.h. (345 km/h).  The minimum surface pressure was 908 mb.

Hurricane Polo strengthened back to Category 5 early on Friday.  A circular eye with a diameter of 17 miles (28 km) was at the center of Polo’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 Polo.  Storms near the center of Polo generated upper level divergence that pumped more mass away from the hurricane.  The removal of more mass in the upper levels caused the surface pressure to decrease again early  on Friday.

The circulation around Hurricane Polo was very symmetrical.  Winds to hurricane force extended out 40 miles (65 km) from the center of Polo’s circulation.  Winds to tropical storm force extended out 125 miles (200 km) from the center of Hurricane Polo.

The Hurricane Intensify Index (HII) for Hurricane Polo is 42.2.  The Hurricane Size Index (HSI) is 14.1 and the Hurricane Wind Intensity Size Index (HWISI) is 56.3.  Hurricane Polo is similar in size and intensity to Hurricane Dorian when Dorian hit the Bahamas in 2019.

Hurricane Polo will move through an environment that will be favorable for a  very powerful hurricane during the next 24 hours.  Polo will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the middle of an upper level ridge that is southwest of Mexico. The upper level winds are weak in the middle of the ridge and there will be little vertical wind shear.  Hurricane Polo could intensify more during the next 24 hours unless another eyewall replacement cycle begins.  An upper level trough that is approaching the West Coast of the U.S. will start to cause more vertical wind shear during the weekend.  Hurricane Polo will start to weaken when the vertical wind shear increases.

Hurricane Polo will move around the western part of a high pressure system that is over Mexico.  The high pressure system will steer Polo toward the northwest during the next 24 hours.  On its anticipated track, Hurricane Polo will move south of Baja California on Friday.   The upper level trough that is approaching the West Coast of the U.S. will steer Polo toward the northeast during the weekend.  Polo could reach southern Baja California on Monday.

A Hurricane Warning will likely be issued for a portion of the coast of southern Baja California.

Hurricane Polo will bring strong winds and heavy rain to southern Baja California early next week.  Heavy rain is likely to cause flash floods in some locations.

Elsewhere over the Eastern North Pacific Ocean, Hurricane Odalys intensified to a Category 4 hurricane on the Saffir-Simpson Scale.  At 8:00 a.m. EDT on Friday the center of Hurricane Odalys was located at latitude 17.7°N and longitude 123.0°W which put the center about 975 miles (1570 km) west-southwest of the the southern tip of Baja California.  Odalys was moving toward the north-northeast at 5 m.p.h. (8 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 940 mb.

Nolo Strengthens to a Hurricane

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Former Tropical Storm Nolo strengthened to a hurricane as it moved over the Central North Pacific Ocean south of Hawaii on Thursday evening.  At 11:00 p.m. EDT on Thursday the center of Hurricane Nolo was located at latitude 15.1°N and longitude 155.9°W which put the center about 270 miles (435 km) south of South Point, Hawaii.  Nolo was moving toward the north-northeast at 5 m.p.h. (8 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 984 mb.

A Hurricane Watch is in effect for Hawaii County.

A Tropical Storm Warning is in effect for Hawaii County.

A Tropical Storm Watch is in effect for Maui County including Maui, Lanai, Molokai, and Kahoolawe.

The inner end of a rainband wrapped around the eastern and southern sides of the center of Hurricane Nolo.  A large circular eye appeared to be forming at the center of Nolo’s circulation.  They eye was surrounded by a broken ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Thunderstorms were also occurring in bands in the western side of Hurricane Nolo.  Bands in the eastern side of Nolo’s circulation consisted primarily of showers and lower clouds.  Storms near the center of Nolo generated upper level divergence that pumped mass away from the hurricane.  The removal of mass caused the surface pressure to decrease.

Winds to hurricane force extended out 30 miles (50 km) from the center of Hurricane Nolo.  Winds to tropical storm force extended out 105 miles (165 km) from the center of Nolo’s circulation.

Hurricane Nolo will move through an environment that will be somewhat favorable for intensification during the next 24 hours.  Nolo will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the southeastern part of an upper level trough that is northwest of Hawaii.  The upper level trough will produce southwesterly winds that will blow toward the top of Nolo’s circulation.  Those winds will cause some vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  Hurricane Nolo will intensify gradually during the next 24 hours.  Nolo could strengthen to a major hurricane during the weekend.

The upper level trough that is northwest of Hawaii will pull Hurricane Nolo slowly toward the north during the next 24 hours.  On its anticipated track, Hurricane Nolo will move closer to the Big Island of Hawaii.  A high pressure system north of Hawaii is forecast to strengthen on Saturday.  If the high pressure system strengthens, it will steer Nolo toward the west during the weekend.

The circulation around the northern side of Hurricane Nolo could drop heavy rain on parts of the Big Island of Hawaii and on Maui.

Flood Watches are in effect for the Big Island of Hawaii, Maui, Lanai, Molokai, and Kahoolawe.