Tag Archives: HWISI

Willa Rapidly Intensifies Into a Major Hurricane, Warnings Issued for Mexico

Hurricane Willa intensified rapidly into a major hurricane on Sunday and Warnings were issued for Mexico.  At 11: 00 p.m. EDT on Sunday the center of Hurricane Willa was located at latitude 17.7°N and longitude 107.2°W which put it about 210 miles (340 km) south-southwest of Cabo Corrientes, Mexico.  Willa was moving toward the north-northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 145 m.p.h. (230 km/h) and there were wind gusts to 170 m.p.h. (275 km/h).  The minimum surface pressure was 941 mb.  Hurricane Willa was a Category 4 hurricane on the Saffir-Simpson Scale.

A Hurricane Warning was in effect for the portion of the coast from San Blas to Mazatlan, Mexico.  A Tropical Storm Warning was in effect for the portion of the coast from Playa Perula to San Blas.  A Tropical Storm Warning was also in effect for the portion of the coast from Mazatlan to Bahia Tempehuaya.

Hurricane Willa intensified from a tropical storm to a Category 4 hurricane in 24 hours.  A small circular eye formed at the center of Hurricane Willa.  The eye was surround by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of Hurricane Willa.  Storms near the core were generating strong upper level divergence which was pumping large quantities of mass away from the hurricane.  The strong divergence allowed the surface pressure to decrease quickly and that caused the wind speeds to increase rapidly.

Willa is a small hurricane.  Winds to hurricane force only extend out about 25 miles (40 km) from the center of Hurricane Willa.  Winds to tropical storm force only extend out about 90 miles (145 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Hurricane Willa is 29.9.  The Hurricane Size Index (HSI) is 8.2 and the Hurricane Wind Intensity Size Index (HWISI) is 38.1.

Hurricane Willa will move through an environment favorable for intensification during the next 12 to 24 hours.  Willa will move over water where the Sea Surface Temperature is near 29°C.  It will move through a region where the upper level winds are weak and there will not be much vertical wind shear.  Hurricane Willa could strengthen to a Category 5 hurricane on the Saffir-Simpson Scale during the next 12 hours.  An upper level trough near the west coast of the U.S. will produce southwesterly winds which will start to affect Hurricane Willa in about 24 hours.  Those winds will cause vertical wind shear, which will cause Willa to start to weaken.

Hurricane Willa will move around the western end of a ridge of high pressure over Mexico.  The ridge will steer Willa toward the north on Monday.  The upper level trough near the west coast of the U.S. will turn Hurricane Willa toward the northeast on Tuesday.  On its anticipated track Hurricane Willa could make landfall on the coast of Mexico on Tuesday night.  Willa could be a major hurricane when it approaches the coast.  It will be capable of causing major wind damage and a significant storm surge along the coast.  Willa will also drop locally heavy rain and it could flash floods when it moves inland over Mexico.

Elsewhere over the Eastern North Pacific Ocean Tropical Storm Vicente was moving near the southeastern periphery of Hurricane Willa.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Vicente was located at latitude 13.9°N and longitude 98.7°W which put it about 220 miles (355 km) south-southeast of Acapulco, Mexico.  Vicente was moving toward the west at 10 m.p.h. (16 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 1005 mb.

Tropical Cyclone Titli Brings Wind and Rain to India

Tropical Cyclone Titli brought wind and rain to India on Wednesday night when it made landfall.  At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone Titli was located at latitude 19.1°N and longitude 84.4°E which put it about 30 miles (50 km) southwest of Brahmapur, India.  Titli was moving toward the west-northwest at 10 m.p.h. (16 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 955 mb.

Tropical Cyclone Titli intensified rapidly on Wednesday prior to making landfall on the coast of India near Brahmapur.  An eye developed at the center of circulation and a ring of strong thunderstorms formed around the eye.  The strongest winds were occurring in that ring of storms.  Winds to hurricane/typhoon force extended out about 50 miles (80 km) from the center of Tropical Cyclone Titli.  Winds to tropical storm force extended out about 170 miles (275 km) from the center of circulation.

The Hurricane Intensity Index (HII) for Tropical Cyclone Titli was 17.8.  The Hurricane Size Index (HSI) was 16.3 and the Hurricane Wind Intensity Index (HWISI) was 34.1.  Tropical Cyclone Titli was capable of causing regional serious damage.

Tropical Cyclone Titli will move around the western end of an upper level ridge over the Bay of Bengal.  The ridge will steer Titli toward the north during the next 24 hours and then the tropical cyclone will move toward the northeast in a day or so.  On its anticipated track Tropical   Cyclone Titli will move slowly northward in Orissa state in India on Friday.  Titli will cause wind damage and it will drop locally heavy rain over Orissa.  The heavy rain could cause flash floods in some locations.  Tropical Cyclone Titli will spin down slowly as it moves north over Orissa.

Hurricane Michael Makes Landfall in Northwest Florida

Powerful Hurricane Michael made landfall in Northwest Florida Wednesday afternoon.  The center of Hurricane Michael officially made landfall between Panama City and Mexico Beach, Florida.  At 2:00 p.m. EDT on Wednesday the center of Hurricane Michael was located at latitude 30.0°N and longitude 85.5°W which put it about 20 miles (30 km) southeast of Panama City, Florida.  Michael was moving toward the north-northeast at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 155 m.p.h. (250 km/h) and there were wind gusts to 180 m.p.h. (290 km/h).  The minimum surface pressure was 919 mb.

Hurricane Michael intensified rapidly right up to landfall on the Gulf Coast.  The minimum surface pressure decreased from 933 mb to 919 mb in the six hours prior to landfall.  With a maximum sustained wind speed of 155 m.p.h. (250 km/h) Hurricane Michael was at the top end of Category 4 on the Saffir-Simpson Scale.  Michael is the strongest hurricane on record to make landfall on that portion of the Gulf Coast and it was one of the most intense hurricanes to make landfall anywhere along the coast of the U.S. during the month of October.

Even though Hurricane Michael is moving inland, a Hurricane Warning remains in effect for the portion of the coast from the Alabama-Florida border to Suwanee River, Florida.  A Tropical Storm Warning is in effect from the Suwanee River to Chassahowitzka, Florida.  A Tropical Storm Warning is also in effect for the Atlantic Coast from Fernandina Beach, Florida to Duck, North Carolina including Albemarle and Pamlico Sounds.  A Tropical Storm Watch remains in effect from Chassahowitzka to Anna Maria Island, Florida.

Winds to hurricane force extended out about 45 miles (75 km) from the center of Hurricane Michael at the time of landfall.  Winds to tropical storm force extended out about 185 miles (290 km) from the center of circulation.  The Hurricane Intensity Index (HII) was 33.3.  The Hurricane Size Index (HSI) was 16.1 and the Hurricane Wind Intensity Size Index (HWISI) was 49.4.  Hurricane Michael will cause regional significant damage.

Tyndall Air Force Base reported a wind gust of 119 m.p.h. (191 km/h).  The Florida State University Panama City Campus reported a wind gust of 116 m.p.h. (187 km/h).   The Panama City Treatment Plant reported a wind gust of 94 m.p.h. (151 km/h).

The coast along the northeastern Gulf of Mexico is very vulnerable to storm surges.  The winds were pushing water toward the coast in the eastern half of the circulation of Hurricane Michael.  Some locations could have a storm surge of 10 to 15 feet (3 to 5 meters).  There have already been reports of damage due to storm surge.

An upper level trough will steer Hurricane Michael toward the northeast.  Michael will weaken as it moves inland, but it will carry hurricane force winds over northeastern Florida, extreme southeastern Alabama and southern Georgia.  The center of Hurricane Michael will pass between Dothan, Alabama and Tallahasse, Florida.  it will move toward Albany, Georgia and then pass south of Macon, Georgia.  Michael will move across South Carolina and North Carolina as a tropical storm before exiting the U.S. near Norfolk, Virginia.

Hurricane Michael will cause widespread power outages and numerous outages are already occurring in northwest Florida.  Michael will also produce locally heavy rain and flash floods could occur as it moves inland.  Wind and rain will disrupt efforts in South Carolina and North Carolina to recover from the effects of Hurricane Florence.

One of the most unusual aspects of Hurricane Michael was that it intensified rapidly right up until it made landfall in northwest Florida.  In the past most major hurricanes weakened while they approached the coast along the northern Gulf of Mexico.  Those hurricanes encountered drier air and more vertical wind shear and they weakened.  The Sea Surface Temperatures in the northern Gulf of Mexico is 2°C to 3°C warmer than normal and that may have contributed to the rapid intensification of Hurricane Michael before landfall.  Hurricane Camille in 1969 also intensified right up until it made landfall in Mississippi.  However, Camille occurred in August, while Hurricane Michael occurred in October.

Powerful Hurricane Michael Nearing North Florida

Powerful hurricane Michael was nearing north Florida on Wednesday morning.  Michael intensified rapidly to Category 4 on the Saffir-Simpson Scale during the overnight hours.  At 8:00 a.m. EDT on Wednesday the center of Hurricane Michael was located at latitude 29.0°N and longitude 86.3°W which put it about 90 miles south-southwest of Panama City, Florida.  Michael was moving toward the north at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 145 m.p.h. (230 km/h) and there were wind gusts to 170 m.p.h. (275 km/h).  The minimum surface pressure was 933 mb.

A Hurricane Warning was in effect for the portion of the coast from the Alabama-Florida border to Suwanee River, Florida.  Tropical Storm Warnings were in effect for the portions of the coast from the Alabama-Florida border to the Alabama-Mississippi border and from Suwanee River to Chassahowitzka, Florida.  A Tropical Storm Warning was in effect for the Atlantic Coast from Fernandina Beach, Florida to Surf City, North Carolina.  Tropical Storm Watches were in effect for the portions of the coast from the Alabama-Mississippi border to the Mouth of the Pearl River and from Chassahowitzka to Anna Maria Island, Florida.  A Tropical Storm Watch was also in effect from Surf City to Duck, North Carolina including Albemarle and Pamlico Sounds.

Hurricane Michael intensified rapidly during the past 12 hours.  An eye with a diameter of 20 miles (32 km) is surrounded by a ring of strong thunderstorms.  The strongest winds are occurring in that ring of storms.  Storms near the core of Hurricane Michael are generating strong upper level divergence which is pumping large quantities of mass away from the hurricane.  The removal of mass allowed the surface pressure to decrease rapidly to 933 mb.

Winds to hurricane force extend out about 45 m.p.h. (75 km/h) from the center of Hurricane Michael.  Winds to tropical storm force extend out about 185 miles (290 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Hurricane Michael is 29.9.  The Hurricane Size Index (HSI) is 16.1 and the Hurricane Wind Intensity Size Index (HWISI) is 46.0.  Hurricane Michael is capable of causing regional significant damage.

Hurricane Michael is stronger than any other hurricane to hit north Florida in the historical record.  Michael is similar in intensity to what Hurricane Charley was when Charley hit southwest Florida in 2004.  Hurricane Michael is bigger than Charley was in 2004.

An upper level trough over the Central U.S. and a subtropical high pressure system over the western Atlantic Ocean are combining to steer Hurricane Michael toward the north.  The trough will turn Michael toward the northeast when it reaches the coast.  On its anticipated track Hurricane Michael will make landfall near Panama City and Port St. Joe, Florida in about six hours.

Hurricane Michael will bring destructive winds to the coast of north Florida.  The strongest winds will be near the center and east of the center.  Those winds will push water toward the coast and a storm surge of 10 to 15 feet (3 to 5 meters) will occur east of where the center of Michael makes landfall.  The coast of the northeast Gulf of Mexico is very vulnerable to storm surges and significant damage will occur.

The center of Hurricane Michael will move between Dothan, Alabama and Tallahassee, Florida.  It will pass near Albany, Georgia and then move south of Macon, Georgia.  The center of Michael could move near Columbia, South Carolina and then it could exit the East Coast of the U.S. near Norfolk, Virginia.

Michael will bring hurricane force winds to northeast Florida, extreme southeast Alabama and southern Georgia.  There will be widespread power outages.  Winds to tropical storm force will occur in South Carolina and North Carolina.  Hurricane Michael will drop locally heavy rain when it moves inland.  The wind and rain will disrupt efforts to recover from the effects of Hurricane Florence in South Carolina and North Carolina.

Michael Strengthens to a Major Hurricane

Hurricane Michael strengthened into a major hurricane on Tuesday afternoon.  At 5:00 p.m. EDT on Tuesday the center of Hurricane Michael was located at latitude 26.0°N and longitude 86.4°W which put it about 290 miles (470 km) south of Panama City, Florida.  Michael was moving toward the north 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. (225 km/h).  The minimum surface pressure was 957 mb.

A Hurricane Warning is in effect for the portion of the coast from the Alabama-Florida border to the Suwanee River, Florida.  Tropical Storm Warnings are in effect for the portions of the coast from the Alabama-Florida border to the Alabama-Mississippi border, from Suwanee River to Chassahowitzka, Florida and from Fernandina Beach, Florida to South Santee River, South Carolina on the Atlantic Coast.  Tropical Storm Watches are in effect for the portions of the coast from the Alabama-Mississippi border to the Mouth of the Pearl River, from Chassahowitzka to Anna Maria Island, Florida and from South Santee, River South Carolina to Duck, North Carolina including Albemarle and Pamlico Sounds.

The inner core of Hurricane Michael tightened on Tuesday afternoon.  The diameter of the eye decreased from 30 miles (50 km) to 22 miles (35 km).  The ring of thunderstorms around the eye tightened around the smaller eye and the strongest winds were closer to the center of circulation.  Storms around the core of Michael were generating upper level divergence which was pumping mass away from the hurricane.  The removal of mass allowed the surface pressure to decrease from 965 mb to 957 mb during the past six hours.

Winds to hurricane force extend out about 45 miles (75 km) from the center of Hurricane Michael.  Winds to tropical storm force extend out about 170 miles (280 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Hurricane Michael is 22.1.  The Hurricane Size Index (HSI) is 14.6 and the Hurricane Wind Intensity Size Index (HWISI) is 36.7.  Hurricane Michael is capable of causing regional major damage.

Hurricane Michael will move through an environment favorable for intensification for another 12 to 18 hours.  Michael will move over water where the Sea Surface Temperature is near 29°C.  An upper level trough over the Central U.S. is producing westerly winds which are blowing toward the top of Hurricane Michael, but those winds are not causing enough vertical wind shear to prevent intensification.  Hurricane Michael could intensify to Category 4 on the Saffir-Simpson Scale before it makes landfall.

Hurricane Michael is moving between a subtropical high pressure system over the western Atlantic Ocean and the upper level trough over the Central U.S.  Those two weather systems are steering Michael toward the north and that general motion is expected to continue for another 12 hours.  On its anticipated track Hurricane Michael will make landfall near Panama City and Port St. Joe, Florida early on Wednesday afternoon.  The upper level trough will steer Michael more toward the northeast after it makes landfall.  The center of Michael is likely to move between Dothan, Alabama and Tallahassee, Florida and it could pass near Albany, Georgia.

Hurricane Michael will bring strong winds to northwest Florida, extreme southeast Alabama and southern Georgia.  There will be wind damage and widespread power outages could occur.  The coast of the northeastern Gulf of Mexico is very vulnerable to storm surges.  Hurricane Michael will produce a storm surge of 10 to 15 feet (3 to 5 meters) at some points along the coast.  Michael will drop locally heavy rain.  Although Hurricane Michael will weaken when it moves inland, it will bring gusty winds and heavy rain to South Carolina and North Carolina.  Hurricane Michael will hinder efforts in those states to recover from the effects of Hurricane Florence.

Michael Strengthens Into a Hurricane, Watches Issued for Gulf Coast

Former Tropical Storm Michael strengthened into a hurricane on Monday morning and Watches were issued for portions of the Gulf Coast.  At 11:00 a.m. EDT on Monday the center of Hurricane Michael was located at latitude 21.2°N and longitude 84.9°W which put it about 50 miles (80 km) south of the western end of Cuba.  Michael was moving toward the north at 7 m.p.h. (11 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 982 mb.

A Hurricane Watch was in effect for the portion of the coast from the Alabama-Florida border to Suwanee River, Florida.  Tropical Storm Watches were in effect for the portions of the coast from the Alabama-Florida border to the Alabama-Mississippi border and from Suwanee River to Anna Maria Island, Florida.  A Hurricane Warning was in effect for the Cuban province of Pinar del Rio.  Tropical Storm Warnings were in effect for the Cuban province of Isle of Youth and for the portion of the coast from Tulum to Cabo Catoche, Mexico.

Hurricane Michael continued to organize quickly.  A circular eye with a diameter of about 30 miles (50 km) was forming at the center of Michael.  A ring of strong thunderstorms was wrapping around the eye and the strongest winds were occurring in the ring of storms.  Several bands of showers and thunderstorms were wrapping around the core of Hurricane Michael.  Storms near the core were generating upper level divergence which was pumping mass away from the hurricane.

Winds to hurricane force extended out about 30 miles (50 km) primarily to the northeast of the center of Hurricane Michael.  Winds to tropical storm force extended out about 175 miles (280 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Hurricane Michael was 10.4.  The Hurricane Size Index (HSI) was 6.8 and the Hurricane Wind Intensity Size Index (HWISI) was 17.2.

Hurricane Michael will move into an environment that will become increasingly favorable for intensification.  Michael will move over water where the Sea Surface Temperature is near 30°C.  An upper level trough over the Gulf of Mexico was producing westerly winds which were blowing toward the top of the circulation.  Those winds were causing some vertical wind shear.  However, the upper level trough will move westward away from Hurricane Michael and the wind shear will decrease.  Hurricane Michael will continue to strengthen when it moves over the Gulf of Mexico and it could intensify rapidly once the eye and eyewall are fully formed.  Hurricane Michael is likely to strengthen into a major hurricane.

Hurricane Michael will move around the western end of a subtropical high pressure system centered over the western Atlantic Ocean.  The high will steer Michael in a northerly direction during the next several days.  It will get bigger and stronger during the next 48 hours.  On its anticipated track Hurricane Michael will approach the northeast coast of the Gulf of Mexico on Wednesday.  It is likely to be a major hurricane at that time.  Hurricane Michael has the potential to cause a storm surge of 10 to 15 feet (3 to 5 meters) at the coast.  It will bring strong winds which could cause regional major damage and result in significant power outages.  Locally heavy rain could cause flooding in some locations.

Major Hurricane Sergio Churns Southwest of Baja California

Major Hurricane Sergio churned southwest of Baja California.  At 5:00 p.m. EDT on Wednesday the center of Hurricane Sergio was located at latitude 13.3°N and longitude 117.9°W which put it about 845 miles (1360 km) southwest of the southern tip of Baja California.  Sergio was moving toward the northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 145 m.p.h. (230 km/h).  The minimum surface pressure was 955 mb.

Hurricane Sergio is a well organized hurricane.  There is a circular eye at the center of circulation.  A ring of strong thunderstorms surrounds the eye and the strongest winds are occurring in that ring of storms.  Several bands of showers and thunderstorms are revolving around the core of Hurricane Sergio.  Storms near the core are generating strong upper level divergence which is pumping mass away in all directions from the hurricane.

Winds to hurricane force extend out about 45 miles (75 km) from the center of Hurricane Sergio.  Winds to tropical storm force extend out about 150 miles (240 km) from the center of circulation.  The Hurricane intensity Index (HII) for Hurricane Sergio is 23.6.  The Hurrricane Size Index (HSI) is 15.1 and the Hurricane Wind Intensity Size Index (HWISI) is 38.7.

Hurricane Sergio will remain in an environment capable of supporting a major hurricane for several more days.  Sergio will move over water where the Sea Surface Temperature is near 28°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Hurricane Sergio could strengthen to Category 4 on the Saffir-Simpson Scale.  Hurricane Sergio will move over cooler water in a couple of days and it is likely to weaken when that occurs.

Hurricane Sergio will move south of a subtropical ridge over the Eastern North Pacific Ocean.  The ridge will steer Sergio toward the northwest during the next day or so.  The ridge is forecast to strengthen on Friday and it will steer Sergio more toward the west when that happens.  On its expected track Hurricane Sergio will move gradually farther away from Baja California.

Typhoon Kong-rey Quickly Strengthens Into Equivalent of Cat. 5 Hurricane

Typhoon Kong-rey quickly strengthened into the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale on Monday.  At 11:00 p.m. EDT on Monday the center of Typhoon Kong-rey was located at latitude 17.9°N and longitude 137.3°E which put it about 690 miles (1110 km) southeast of Okinawa.  Kong-rey was moving toward the west-northwest at 11 m.p.h. (17 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 910 mb.

The circulation of Typhoon Kong-rey was very organized and symmetrical.  There was a circular eye at the center of Kong-rey.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of Typhoon Kong-rey.  Storms near the core were generating strong upper level divergence which was pumping mass away from the typhoon in all directions.

Kong-rey is a large typhoon.  Winds to typhoon force extend out about 75 miles (120 km) from the center of circulation.  Winds to tropical storm force extend out about 240 miles (390 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Kong-rey is 35.0.  The Hurricane Size Index (HSI) is 26.8 and the Hurricane Wind Intensity Size Index (HWISI) is 61.8.  Typhoon Kong-rey is capable of causing widespread catastrophic damage.

Typhoon Kong-rey will remain in an environment very favorable for strong typhoons for another 24 to 36 hours.  Kong-rey will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  If a rainband wraps around the existing eye and eyewall, then an eyewall replacement cycle could cause Typhoon Kong-rey to weaken.  An upper level trough near Taiwan will produce southwesterly winds which will cause the vertical wind shear to increase in a couple of days.  Kong-rey will weaken more steadily when the wind shear increases.

Typhoon Kong-rey will move around the western end of a subtropical high pressure system over the Western North Pacific Ocean.  The high will steer Kong-rey toward the northwest for several more days.  On its anticipated track Typhoon Kong-rey could approach the Rykyu Islands in 48 to 60 hours.  It will still be a typhoon at that time.  If Typhoon Kong-rey brings strong winds and heavy rain, it will hamper the recovery from Typhoon Trami which hit the Ryukyu Islands a few days ago.

Hurricane Walaka Rapidly Intensifies to Category 5

Hurricane Walaka rapidly intensified to Category 5 on the Saffir-Simpson Scale on Monday.  At 11:00 p.m. EDT on Monday the center of Hurricane Walaka was located at latitude 13.2°N and longitude 169.8°W which put it about 240 miles (390 km) south of Johnston Atoll.  Walaka was moving toward the northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 195 m.p.h. (315 km/h).  The minimum surface pressure was 920 mb.

A Hurricane Warning is in effect for Johnston Atoll.  A Hurricane Watch is in effect for the Papahanaumokuakea Marine National Monument from Nihoa to French Frigate Shoals to Maro Reef.

The circulation of Hurricane Walaka is very well organized,  There is a circular eye at the center of Walaka.  The eye is surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of Hurricane Walaka.  Storms near the core were generating strong upper level divergence which was pumping mass away from the hurricane in all directions.

Winds to hurricane force extended out about 50 miles (80 km) from the center of Hurricane Walaka.  Winds to tropical storm force extended out about 185 miles (300 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Hurricane Walaka was 35.0.  The Hurricane Size Index (HSI) was 16.4 and the Hurricane Wind Intensity Size Index (HWISI) was 51.4.

Hurricane Walaka will remain in an environment very favorable for strong hurricanes for several more days.  Walaka will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds will be weak and there will be little vertical wind shear.  If a rainband wraps around the existing eye and eyewall, then an eyewall replacement cycle could cause Hurricane Walaka to weaken.  In several days Walaka will move into an area where the upper level winds are stronger and the vertical wind shear will increase.  Hurricane Walaka will weaken more quickly when the shear increases.

Hurricane Walaka is moving around the western end of a subtropical high pressure system.  The high pressure system will steer Walaka toward the north during the next several days.  On its anticipated track Hurricane Walaka will pass near Johnston Atoll on Tuesday.

Large Typhoon Trami Brings Wind and Rain to Japan

Large Typhoon Trami brought wind and rain to Japan on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Typhoon Trami was located at latitude 31.8°N and longitude 132.3°E which put it about 140 miles (225 km) southwest of Kochi, Japan.  Trami was moving toward the northeast at 22 m.p.h. (33 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 950 mb.

There was still a large eye at the center of Typhoon Trami, but the ring of thunderstorms around the eye was beginning to look a little more ragged.  However, the circulation around Trami was very large.  Winds to typhoon force extended out about 155 miles (250 km) from the center of circulation.  Winds to tropical storm force extended out about 355 miles (575 km) from the center.

The Hurricane Intensity Index (HII) for Typhoon Trami was 17.8.  The Hurricane Size Index (HSI) was 49.6 and the Hurricane Wind Intensity Size Index (HWISI) was 67.4.  Typhoon Trami was capable of causing extensive serious damage.

Typhoon Trami brought strong winds and heavy rain to Okinawa and the northern Ryukyu Islands on Saturday.  There were reports of damage.  The northern eyewall of Trami passed over Kyushu.  Strong winds and heavy rain were falling in that region.  Heavy rain and strong winds will reach Shikoku shortly.  The center of Typhoon Trami could be near Kyoto in about six hours.  Trami will move northeast across Honshu on Sunday.  It will bring heavy rain and gusty winds to much of Japan.  Flash flooding will be possible over much of Japan.

Elsewhere over the Western North Pacific Ocean Tropical Storm Kong-rey was strengthening southeast of the Ryukyu Islands.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Kong-rey was located at latitude 14.1°N and longitude 138.1°E which put it about 1165 miles (1880 km) east of Manila, Philippines.  Kong-rey was moving toward the west-northwest at 13 m.p.h. (20 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 983 mb.