Tag Archives: Hawaii

Olaf Becomes a Hurricane Between Baja and Hawaii

The core of the circulation of Olaf consolidated on Sunday and the National Hurricane Center upgraded it to a hurricane.  At 11:00 a.m. EDT on Sunday the center of Hurricane Olaf was located at latitude 9.5°N and longitude 133.2°W which put it about 1620 miles (2610 km) east-southeast of Hilo, Hawaii.  Olaf was moving toward the west at 12 m.p.h. (19 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. (155 km/h).  The minimum surface pressure was 989 mb.

The circulation of Hurricane Olaf consists of a small core of thunderstorms around the center of circulation and a primary rainband that spirals around the western and southern sides of the hurricane.  The core of thunderstorms is producing some upper level divergence, but upper level winds are inhibiting the outflow on the western side of the center.

Hurricane Olaf is moving over water where the Sea Surface Temperature is near 30°C and there is plenty of energy in the upper ocean to support intensification.  However, an upper level trough north of Olaf is producing westerly winds which are blowing over the top of the hurricane.  The upper level winds are blocking upper level outflow on the western side of Olaf and the vertical wind shear is inhibiting the intensification of Olaf.  If the wind shear decreases, then further intensification will be possible.

A subtropical ridge is steering Hurricane Olaf toward the west and that general motion is expected to continue for another day or two.  When Olaf reaches the western end of the ridge, it will start to turn more toward the north.

Tropical Storm Nora Moves Into the Central Pacific

Tropical Storm Nora moved west of longitude 140°W on Sunday which meant that it officially crossed from the Eastern North Pacific into the Central North Pacific Ocean.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Nora was located at latitude 13.5°N and longitude 143.8°W which put it about 860 miles (1385 km) east-southeast of Hilo, Hawaii.  Nora was moving toward the west-northwest at 9 m.p.h. (15 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 m.p.h.).  The minimum surface pressure was 993 mb.

Nora is a small tropical storm.  Wind to tropical storm force only extend out about 70 miles (110 km) from the center of circulation.  Most of the stronger thunderstorms are located northwest of the center of circulation and there is not much deep convection in the other parts of Nora.  Although Nora is over water where the Sea Surface Temperature is near 29°C, southerly winds in the upper levels appear to be causing vertical wind shear.  The wind shear is likely to increase as an upper level trough north of Hawaii gets closer to Nora.

Tropical Storm Nora is nearing the western end of a subtropical ridge which has been steering it toward the west.  If the vertical structure of Nora remains intact, the tropical storm should turn toward the north during the next day or two.  After that time the upper level trough north of Hawaii could sweep Nora toward the northeast.  An alternate and possibly more likely scenario, given the small size of Tropical Storm Nora, is that the vertical wind shear blows the upper portion of the circulation north of the surface circulation.  If that happens, then the surface circulation will be steered westward until it dissipates by the winds in the lower atmosphere.

Tropical Storm Nora Form Far East of Hawaii

Another Tropical Cyclone has formed over the Eastern North Pacific Ocean well east of Hawaii and the National Hurricane Center has upgraded Tropical Depression 18-E to Tropical Storm Nora.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Nora was located at latitude 11.3°N and longitude 135.1°W which put it about 1470 miles (2365 km) east-southeast of South Point Hawaii.  Nora was moving toward the west at 16 m.p.h. (26 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 1006 mb.

The circulation inside Tropical Storm Nora is still in the process of organizing.  There is one primary rainband that wraps around the western and southern side of the tropical storm.  More thunderstorms are forming near the center, but a clearly defined core of convection has not yet developed.  The storms close to the center of circulation are producing more upper level divergence which is pumping out mass.

Tropical Storm Nora is in an environment that favors intensification,   The Sea Surface Temperature is warmer than 29°C,  The upper level winds are light and there is not much upper level divergence.  Nora is expected to intensify gradually into a hurricane.  Once a tight, well organized inner core develops, it could intensify more quickly.

A subtropical ridge north of Nora is steering the tropical storm westward.  That general steering pattern is expected to continue for another day or two.  When Nora reaches the western end of the subtropical ridge, it is expected to turn toward the north.

Oho Becomes a Hurricane Southeast of Hawaii

The circulation around Tropical Storm Oho became much more organized on Tuesday and it intensified into a hurricane.  At 5:00 p.m. EDT on Tuesday the center of Hurricane Oho was located at latitude 16.6°N and longitude 150.2°W which put it about 385 miles (620 km) east-southeast of Hilo, Hawaii.  Oho was moving toward the northeast at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 85 m.p.h. (140 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 975 mb.

A primary rainband wrapped tightly around the center of circulation and created a banded eye feature.  In addition other rainbands developed around the core of the circulation and Oho looks much more like a tropical cyclone today.  Thunderstorms near the center of circulation are generating upper level divergence, especially northeast of the center.  The upper level divergence caused the surface pressure to decrease and the wind speeds to increase.

Hurricane Oho is moving over water where the Sea Surface Temperature (SST) is near 28°C.  The upper level winds are currently fairly light and there is not much vertical wind shear.  The conditions are favorable for intensification and Oho could get stronger during the next 24 hours.  After that time Oho will move over cooler SSTs and the vertical wind shear will increase.  Oho should start to weaken and begin a transition to an an extratropical cyclone.

A large upper level trough north of Hawaii will steer Hurricane Oho toward the northeast during the next few days.  On its anticipated track Oho will pass about 400 miles east of Hawaii.  The extratropical stage of Hurricane Oho could approach the Pacific Northwest in three or four days.

Tropical Storm Oho Passing Southeast of Hawaii

Tropical Storm Oho moved slowly southeast of Hawaii on Monday.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Oho was located at latitude 15.0°N and longitude 153.6°W which put it about 340 miles (545 km) south-southeast of Hilo, Hawaii.  Oho was moving toward the northeast at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 984 mb.

Tropical Storm Oho is only partially organized.  A partial eyewall wrapped around the western and southern sides of the center of circulation.  However, most of the stronger thunderstorms are located southwest of the center.  A weak upper level ridge south of Hawaii appears to be generating some northeasterly winds over the top of Oho, which is causing some vertical wind shear.  The wind shear is inhibiting the organization of the circulation of the tropical storm.

Tropical Storm Oho is over water where the Sea Surface Temperature (SST) is near 28.5°C.  The wind shear could decrease on Tuesday and that could allow Oho to increase to hurricane intensity.  Oho will move northward over cooler SSTs later this week.  A combination of cooler water and more vertical wind shear will cause Oho to weaken and make a transition to an extratropical cyclone.

A large upper level trough northwest of Hawaii is expected to move eastward and begin to steer Oho toward the northeast.  On its expected track, Oho will pass southeast of Hawaii.  The extratropical cyclone that is currently Tropical Storm Oho could be approaching the west coast of the U.S. by the weekend.

Shear Hits Tropical Storm Niala and It Turns West

After intensifying earlier on Saturday, vertical wind shear began to affect Tropical Storm Niala and it turned westward.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Niala was located near latitude 16.9°N and longitude 152.8°W which put it about 245 miles (395 km) southeast of Hilo, Hawaii.  Niala was moving toward the west at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 992 mb.  A Tropical Storm Watch remains in effect for Hawaii County.

A large upper level trough centered northeast of Hawaii is causing southwesterly winds that are blowing over Tropical Storm Niala.  The wind shear is blowing the tops off the thunderstorms that try to form near the center of circulation.  As a result the low level circulation is exposed on satellite imagery.  The effect of the wind shear will be to weaken Niala even though it is over warm Sea Surface Temperatures.

Since there are not tall thunderstorms near the center of circulation, it is being steered toward the west by winds lower in the atmosphere.  A general westerly motion is expected for the next several days and Tropical Storm Niala is likely to pass south of Hawaii.

Niala Prompts Tropical Storm Watch for Hawaii

Tropical Storm Niala organized quickly southeast of Hawaii on Friday and the Central Pacific Hurricane Center issued a Tropical Storm Watch for Hawaii County.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Niala was located at latitude 15.7°N and longitude 150.4°W which put it about 415 miles (665 km) southeast of Hilo, Hawaii.  Niala was moving toward the northwest at 7 m.p.h. (11km/h).   The maximum sustained wind speed was 45 m.p.h. (70 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1001 mb.

The circulation inside Niala consolidated quickly around the core of the tropical storm on Friday.  A primary rainband wrapped around the eastern and northern side of the circulation creating a small eyelike feature at the center of circulation.  At least three additional rainbands formed in the eastern half of the tropical storm.  There are fewer thunderstorms in the western half of the circulation which could indicated the presence of drier, more stable air in that part of Niala.

Niala is over water where the Sea Surface Temperatures are nearly 29°C.  The upper level winds are not too strong and the thunderstorms around the core of the circulation are generating upper level divergence,  Niala could strenthen during the next day or so.  A large upper level trough extends from northeast of Hawaii to the islands.  As Niala moves toward the northwest, it will start to move under strong southwesterly winds on the eastern side of the trough.  Those winds will create strong vertical wind shear and Niala will weaken as it approaches Hawaii.

A subtropical ridge is steering Niala toward the northwest and that general motion is expected to continue for another 24 hours.  When the wind shear weakens Niala, the circulation will not extend as high into the atmosphere.  After that time the winds lower in the atmosphere will steer the weakening Niala toward the west.

Trio of Cat. 4 Hurricanes Churn Across the Pacific

A trio of powerful Category 4 hurricanes on the Saffir-Simpson Scale churned across the Central and Eastern North Pacific on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Hurricane Ignacio was located at latitude 17.0°N and longitude 147.6°W which put it about 525 miles (845 km) east-southeast of Hilo, Hawaii.  Ignacio was moving toward the northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 140 m.p.h. (225 km/h) and there wind gusts to 170 m.p.h. (275 km/h).  The minimum surface pressure was 951 mb.

At 11:00 p.m. EDT on Saturday the center of Hurricane Jimena was located at latitude 13.3°N and longitude 127.5°W which put it about 1330 miles (2140 km) west-southwest of the southern tip of Baja California.  Jimena was moving toward the west-northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 140 m.p.h. (225 km/h) and there were wind gusts to 170 m.p.h. (275 km/h).  The minimum surface pressure was 945 mb.

At 11:00 p.m. EDT on Saturday the center of Hurricane Kilo was located at latitude 18.4°N and longitude 176.2°W which put it about 680 miles (1095 km) south of Midway Island.  Kilo was moving toward the west-northwest at 9 m.p.h.  The maximum sustained wind speed was 135 m.p.h. (215 km/h) and there were wind gusts to 155 m.p.h. (250 km/h).  The minimum surface pressure was 948 mb.

Ignacio is the only one of the three powerful hurricane to pose an imminent threat to land.  On its anticipated track Ignacio could be northeast of the Big Island of Hawaii in about 48 hours.  Tropical Storm Watches have been issued for Hawaii County and Maui County including the islands of Maui, Molokai, Lanai and Kahoolawe.  An upper level trough passing north of Hawaii will cause westerly winds and increasing vertical wind shear over Ignacio as it moves closer to Hawaii.  Ignacio should weaken but it could still be a hurricane when it makes its closest approach to Hawaii.  Given the size of the circulation around Ignacio, Tropical Storm Watches were issued for some of the islands.

Jimena may be the most well organized of the three hurricanes.  It has concentric eyewalls and a very symmetrical structure.  Eyewall replacement cycles will cause fluctuations in the intensity of Jimena.  However, it is in a very favorable environment and it could reach Category 5 intensity at some point.  Fortunately, Jimena is about 1500 miles (2420 km) east of Ignacio and it is a long way from any land area.

After days when strong vertical wind shear kept Kilo a weak disorganized tropical depression, it intensified very rapidly during the past 48 hours.  Kilo is over warm Sea Surface Temperatures  and it could intensify a little more.  Kilo is not currently a threat to any land.

Hurricanes Ignacio and Jimena Heading West

Hurricanes Ignacio and Jimena are heading steadily westward over the Pacific Ocean.  At 5:00 p.m. EDT on Friday the center of Hurricane Ignacio was located at latitude 14.6°N and longitude 144.5°W which put it about 785 miles (1260 km) east-southeast of Hilo, Hawaii.  Ignacio was moving toward the northwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 90 m.p.h. (150 km/h) and there were wind gusts to 105 m.p.h. (170 km/h).  The minimum surface pressure was 982 mb.  At 5:00 p.m. EDT on Friday the center of Hurricane Jimena was located at latitude 12.3°N and longitude 123.1°W which put it about 1135 miles (1825 km) southwest of the southern tip of Baja California.  Jimena was moving toward the west at 12 m.p.h. (19 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 972 mb.

Hurricane Ignacio has remained in a relatively steady state during much of today.  It is moving over water where the Sea Surface Temperature is near 29°C, but an upper level trough near Hawaii is causing some vertical wind shear.  Recent satellite images indicate that an eye may be forming and the core of Ignacio’s circulation is becoming better organized.  Ignacio could strengthen during the next day or so before it moves farther west and the vertical wind shear increases.  A subtropical ridge is steering Ignacio toward the west-northwest and that general motion is expected to continue during the weekend.  Ignacio could be approaching the Big Island of Hawaii in about three days.

Hurricane Jimena intensified rapidly on Friday and it is on the verge of becoming a major hurricane.  It has a very well formed eye with a ring of strong thunderstorms around it.  The upper level winds near Jimena are light and upper level divergence is pumping out mass in all directions.  Jimena is over water where the Sea Surface Temperatures are between 29°C and 30°C and further intensification is likely.  Eye replacement cycles could cause periodic fluctuations in the intensity of Jimena.  Jimena is about 1400 miles (2260 km) east of Ignacio and it could eventually move over some cooler water stirred to the surface by the other hurricane.  The subtropical ridge is also steering JImena toward the west and that motion is expected to continue for the next few days.

Ignacio Becomes a Hurricane

The core of Tropical Storm Ignacio organized rapidly on Wednesday and it was upgraded to hurricane status by the National Hurricane Center.  At 11:00 p.m. EDT on Wednesday the center of Hurricane Ignacio was located at latitude 12.2°N and longitude 137.5°W which put it about 1275 miles (2055 km) east-southeast of Hilo, Hawaii.  Ignacio was moving toward the west-northwest at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 992 mb.

A primary rainband wrapped completely around the center of Ignacio and a large eye cleared in the middle of the circulation.   Strong thunderstorms surround the eye in a well formed eyewall.  Other bands of thunderstorms are spiraling around the core of Ignacio.  The upper level winds lessened and the strong convection in the core of Ignacio produced upper level divergence.  The divergence pumped out mass and the surface pressure decreased.  Ignacio is over warm Sea Surface Temperatures.  The environment is favorable for intensification and a period of rapid intensification is possible.  Ignacio could become a major hurricane as it moves across the Central Pacific.

A subtropical ridge is steering Ignacio toward the west.  The ridge is expected to steer the hurricane in a generally west-northwesterly direction during the next few days.  On its anticipated track Ignacio could approach the Big Island of Hawaii in about five days.