Tag Archives: 03C

Tropical Storm Olana Forms East of Date Line

Leave a reply

Tropical Storm Olana formed over the Central North Pacific Ocean just to the east of the International Dateline on Sunday.  At 5:00 p.m. EDT on Sunday the center of Tropical Storm Olana was located at latitude 14.8°N and longitude 178.0°W which put the center about 580 miles (935 km) west-southwest of Johnston Atoll.  Olana was moving toward the east-northeast at 8 m.p.h. (13 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 1002 mb.

A low pressure system over the Central North Pacific Ocean just to the east of the International Dateline strengthened on Sunday and the U.S. National Hurricane Center designated the system as Tropical Storm Olana.

More thunderstorms were forming near the center of Tropical Storm Olana.  Thunderstorms were also occurring in bands in the eastern side of Olana’s circulation.  Bands in the western side of Tropical Storm Olana consisted primarily of showers and lower clouds.  Storms near the center of Olana 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.

The circulation around Tropical Storm Olana was small.  Winds to tropical storm force extended out 45 miles (75 km) from the center of Olana’s circulation.

Tropical Storm Olana will move through an environment that will be marginally favorable for intensification during the next 24 hours.  Olana 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 over the North Pacific Ocean.  The upper level trough will produce southwesterly winds that will blow toward the top of Olana’s circulation.  Those winds will cause moderate vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear may not be enough to prevent intensification.  Tropical Storm Olana could intensify a little during the next 24 hours, if the upper level winds to not get any stronger.

The upper level trough will steer Tropical Storm Olana toward the east-northeast during the next 24 hours.  On its anticipated track, Tropical Storm Olana will move closer to Johnston Atoll.

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.