Tag Archives: Oahu

Tropical Storm Olivia Nears Hawaii

Tropical Storm Olivia moved closer to Hawaii on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Olivia was located at latitude 21.6°N and longitude 152.3°W which put it about 275 miles (440 km) east of Kahului, Hawaii.  Olivia 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 1000 mb.

Tropical Storm Warnings were in effect for Oahu, Hawaii County, Maui County including Maui, Molokai, Lanai and Kahoolawe, and for Kauai County including Kauai and Niihau.

Tropical Storm Olivia was weakening as it neared Hawaii.  An upper level trough north of Hawaii was producing strong westerly winds which were blowing across the top of the circulation.  Those winds caused significant vertical wind shear and they blew the tops off thunderstorms near the center of circulations.  Bands near the center and in the western half of Tropical Storm Olivia consisted primarily of showers and lower clouds.  There were still a few taller thunderstorms in bands on the far eastern side of the circulation.

Since Tropical Storm Olivia consisted mostly of a circulation in the lower levels of the atmosphere, it was being steered by the winds in the lower levels.  Olivia was moving south of the subtropical high over the central Pacific Ocean.  That high steered Tropical Storm Olivia quickly to the west on Tuesday and it will continue to do so.  On its anticipated track Tropical Storm Olivia will reach Hawaii on Wednesday.  Olivia will bring some gusty winds and it could drop locally heavy rain, especially where the wind rises over hills and mountains.

Hurricane Olivia Causes Tropical Storm Watches for Hawaii

The potential impacts of Hurricane Olivia caused the issuance of Tropical Storm Watches for Hawaii on Sunday night.  Tropical Storm Watches were issued for Oahu, Maui County including Maui, Molokai, Lanai, and Kahoolawe, and Hawaii County.  At 11:00 p.m. EDT on Sunday the center of Hurricane Olivia was located at latitude 21.4°N and longitude 146.1°W which put it about 595 miles (960 km) east-northeast of Hilo, Hawaii.  Olivia was moving toward the west at 12 m.p.h. (19 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 988 mb.

Hurricane Olivia maintained its intensity and structure on Sunday.  A circular eye persisted at the center of circulation and a ring of thunderstorms surrounded the eye.  The strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of Hurricane Olivia.  Winds to hurricane force extended out about 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out about 125 miles (200 km) from the center.

Hurricane Olivia will move through a less favorable environment during the next several days.  Olivia will move over water where the Sea Surface Temperature is near 26°C.  So, there will be enough energy in the upper ocean to support a hurricane.  However, an upper level trough north of Hawaii will produce southwesterly winds which will blow toward the top of Hurricane Olivia.  Those winds will cause more vertical wind shear and Hurricane Olivia could weaken to a tropical storm as it approaches Hawaii.

Hurricane Olivia will move south of a subtropical high pressure system over the Central Pacific Ocean.  The high is forecast to strengthen and it will steer Olivia on a west-southwesterly track.  On its anticipated track Olivia could approach Hawaii late on Tuesday.  Olivia will bring gusty winds and it could cause power outages.  Locally heavy rain and the potential for flash floods are greater risks.

Weakening Tropical Storm Lane Moves Away from Hawaii

A weakening Tropical Storm Lane moved away from Hawaii on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Lane was located at latitude 19.5°N and longitude 160.2°W which put it about 195 miles (310 km) southwest of Honolulu, Hawaii.  Lane was moving toward the west at 9 m.p.h. (15 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 998 mb.  All Tropical Storm Warnings and Watches for the Hawaiian Islands have been discontinued.

An upper level trough west of the Hawaiian Islands produced strong southwesterly winds which blew the upper portion of the circulation of former Hurricane Lane off the lower part of the circulation.  Tropical Storm Lane consisted primarily of a well develop low level circulation of bands of showers and lower clouds.  A few thunderstorms continued to develop in outer bands on the eastern side of the circulation.

Since Tropical Storm Lane exists primarily in the lower levels of the atmosphere, it is being steered westward by a subtropical ridge over the Central Pacific Ocean.  A general westerly motion is forecast during the next several days.  The upper level trough will continue to cause strong vertical wind shear and Tropical Storm Lane will continue to weaken.

Hurricane Lane Edges Closer to Hawaii

Hurricane Lane edged closer to Hawaii on Friday.  At 5:00 p.m. EDT on Friday the center of Hurricane Lane was located at latitude 19.1°N and longitude 157.9°W which put it about 150 miles (245 km) south of Honolulu, Hawaii.  Lane was moving toward the north at 5 m.p.h. (8 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 966 mb.

Hurricane Warnings were in effect for Oahu and Maui County including the islands of Maui, Lanai, Molokai and Kahoolawe.  A Tropical Storm Warning was in effect for Hawaii County.  A Tropical Storm Watch was in effect for Kauai County including Kauai and Niihau.  Flash Flood Watches were in effect for all Hawaiian Islands.

Hurricane Lane weakened gradually on Friday.  There was no longer an eye at the center of circulation.  The strongest thunderstorms were occurring in  a band northwest of the center.  The strongest winds and heaviest rain were occurring in that band of storms.  Other rainbands in the northern half of the circulation were revolving around the center of Hurricane Lane.  The bands in the southern half of the circulation were weaker and they consisted primarily of showers and lower clouds.  Winds to hurricane force extended out about 35 miles from the center of circulation, primarily on the northern side of Lane.  Winds to tropical storm force extended out about 140 miles (225 km) from the center.

Hurricane Lane will continue to weaken on Saturday.  An upper level trough west of the Hawaiian Islands is producing strong southwesterly winds which were causing significant vertical wind shear.  Those winds were tilting the circulation toward the northeast and they were inhibiting upper level divergence to the west of the hurricane.  The slow movement of Hurricane Lane is allowing the wind to mix cooler water to the surface of the ocean.  Significant vertical wind shear and cooler water will cause Lane to weaken.  If the upper level winds become strong enough, there is the chance that they could blow the upper part of the circulation away from the lower level circulation.

The upper level trough will push Hurricane Lane slowly toward the north during the next 12 to 24 hours.  On its anticipated track Hurricane Lane will get closer to Maui and Oahu.  When most of the stronger, taller thunderstorms weaken, then Lane will be steered more by the winds in the lower levels of the atmosphere.  Those winds are blowing from east to west and they are forecast to Lane toward the west just before the center reaches Oahu and Maui.  Although Hurricane Lane will cause gusty winds, locally heavy rain and flash floods are the greatest risks.  Heavy rain has already fallen on the Big Island of Hawaii and Flash Flood Watches have been issued for all of the Hawaiian Islands.

Hurricane Lane Drops Heavy Rain on Hawaii

Hurricane Lane dropped heavy rain on Hawaii on Thursday.  The airport in Hilo, Hawaii reported 14.02 inches (356 mm) of rain during the past 24 hours.  At 11:00 p.m. EDT Thursday the center of Hurricane Lane was located at latitude 17.8°N and longitude 157.9°W which put it about 240 miles (390 km) south of Honolulu, Hawaii.  Lane was moving toward the north-northwest at 6 m.p.h. (10 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 959 mb.

Hurricane Warnings were in effect for Oahu and Maui County including the islands of Maui, Lanai, Molokai and Kahoolawe.  A Hurricane Watch was in effect for Kauai County including the islands of Kauai and Niihau.  A Tropical Storm Warning was in effect for Hawaii County.

Hurricane Lane began to weaken on Thursday.  An upper level trough west of Hawaii was producing southwesterly winds which were blowing toward the top of the hurricane.  Those winds were causing moderate vertical wind shear and they were obstructing upper level divergence to the west of Hurricane Lane.  The wind shear prevented the circulation from pumping as much mass away from the hurricane and the surface pressure began to increase.

Hurricane Lane retained a strong circulation in spite of increased vertical wind shear.  Winds to hurricane force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out 125 miles (205 km) from the center.  The core of Hurricane Lane passed over NOAA buoy 51002.  The strongest winds occurred in the northern eyewall.  The buoy measured a sustained wind speed of 83 m.p.h. (133 km/h).  It also reported a wind gust to 105 m.p.h. (170 km/h).  The winds were significantly weaker in the southern half of the circulation.

The upper level trough gradually turned Hurricane Lane more toward the north on Thursday.  A general motion toward the north is forecast for Friday.  On its anticipated track Hurricane Lane could approach Maui and Oahu on Friday night.  Lane is forecast to weaken further during the next 24 hours.  Guidance from numerical models suggests that the weaker circulation will be steered by winds in the lower levels when it nears Maui and Oahu.  The models are forecasting a turn toward the west.  Hurricane Lane could cause gusty winds and power outages.  The greater risk will be caused by the locally heavy rain, which will create the potential for flash floods.  Flash floods may develop very quickly in areas of steep terrain.

Powerful Hurricane Lane Prompts Hurricane Watches for Hawaii

A potential threat from powerful Hurricane Lane prompted the Central Pacific Pacific Hurricane Center to issued Hurricane Watches for parts of Hawaii on Tuesday morning.  Hurricane Watches were issued for Hawaii County and Maui County including the islands of Maui, Lanai, Molokai and Kahoolawe.  At 11:00 a.m. EDT on Tuesday the center of Hurricane Lane was located at latitude 14.1°N and longitude 152.3°W which put it about 620 miles (995 km) southeast of Honolulu, Hawaii.  Lane was moving toward the west at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 180 m.p.h. (290 km/h).  The minimum surface pressure was 950 mb.

The circulation of Hurricane Lane is very well organized.  There is a circular eye at the center of circulation and the eye is surrounded by a ring of strong thunderstorms.  The strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of Hurricane Lane.  A NOAA P-3 aircraft encountered strong turbulence during a mission into Lane last night and the aircraft will be examined before it flies again.  Storms around the core of the circulation were generating strong upper level divergence which was pumping mass away from the hurricane.

Hurricane Lane has a large symmetrical circulation.  Winds to hurricane force extended out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out about 240 miles (390 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane was 31.6.  The Hurricane Size Index (HSI) was 13.7 and the Hurricane Wind Intensity Size Index (HWISI) was 45.3.  Those indices indicate that Hurricane Lane was stronger and larger than Hurricane Dennis was when Dennis hit the northern Gulf Coast in 2005.

Hurricane Lane will move through an environment capable of supporting a major hurricane for another 24 to 48 hours.  Lane will move over water where the Sea Surface Temperature is between 27°C and 28°C.  It will move through an environment where the upper level winds are weak during the next 24 hours and there will be little vertical wind shear during that time period.  An upper level trough west of Hawaii will move closer to Hurricane Lane on Wednesday.  Southwesterly winds on the eastern side of the trough will increase the vertical wind shear.  Hurricane Lane is likely to weaken on Wednesday, but it could weaken slowly.

Hurricane Lane is moving around the western end of a subtropical ridge over the Eastern North Pacific Ocean.  The ridge has been steering Lane toward the west.  Hurricane Lane will turn more toward the northwest when it reaches the end of the ridge.  The upper level trough could steer Lane more toward the north on Thursday and Friday.  Guidance from forecast models has been trending toward a track closer to Hawaii and that prompted the issuance of Hurricane Watches for some of the Hawaiian Islands.