Tag Archives: Hernan

Tropical Storm Lala Forms, Hurricane Watch for Hawaii

Tropical Storm Lala formed over the Central Pacific Ocean east-southeast of Hawaii on Thursday morning.  A Hurricane Watch was issued for the Big Island of Hawaii.  At 2:00 p.m. EDT on Thursday the center of Tropical Storm Lala was located at latitude 15.4°N and longitude 145.8°W which put the center about 680 miles (1095 km) east-southeast of Hilo, Hawaii.  Lala was moving toward the west-northwest 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 1001 mb.

A Hurricane Watch is in effect for Hawaii County.

More thunderstorms formed near the center of a low pressure system formerly called Potential Tropical Cyclone One-C on Thursday morning and the U.S. Central Pacific Hurricane Center designated the system as Tropical Storm Lala.

The circulation around Tropical Storm Lala exhibited more organization on Thursday.  New thunderstorms were developing near the center of Lala’s circulation.  Other thunderstorms were occurring in bands in the southern and eastern parts of Tropical Storm Lala.  Storms near the center of Lala generated upper level divergence that pumped mass away from the tropical storm.  The removal of mass caused the surface pressure to decrease.

The strongest winds were occurring in the eastern half of Tropical Storm Lala.  Winds to tropical storm force extended out 140 miles (220 km) in the northeastern quadrant of Lala’s circulation.  Winds to tropical storm force extended out 60 miles (95 km) in the southeastern quadrant of Tropical Storm Lala.  The winds in the western half of Lala’s circulation were blowing at less than tropical storm force.

Tropical Storm Lala will move through an environment favorable for intensification during the next 24 hours.  Lala will move over water where the Sea Surface Temperatures are near 27°C.  It will move under the eastern part of an upper level ridge that is east of Hawaii.  The upper level ridge will produce northeasterly winds that will blow toward the top of Lala’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.  Tropical Storm Lala will intensify during the next 24 hours.

Tropical Storm Lala will move around the southern side of a high pressure system over the Central Pacific Ocean.  The high pressure system will steer Lala toward the west-northwest during the next 24 hours.  On its anticipated track, Tropical Storm Lala will move toward Hawaii.  Lala could reach the Big Island of Hawaii on Saturday.

Elsewhere, Tropical Storm Hernan strengthened a little as it moved far to the west of Baja California.  At 11:00 a.m. EDT on Thursday the center of Tropical Storm Hernan was located at latitude 18.0°N and longitude 131.9°W which put the center about 1460 miles (2350 km) west of the the southern tip of Baja California.  Hernan was moving toward the west-southwest at 3 m.p.h. (5 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 1004 mb.

Tropical Storm Hernan Forms West of Baja California

Tropical Storm Hernan formed over the Eastern North Pacific Ocean west of Baja California on Wednesday night.  At 5:00 a.m. EDT on Thursday the center of Tropical Storm Hernan was located at latitude 18.1°N and longitude 131.9°W which put the center about 1460 miles (2350 km) west of the the southern tip of Baja California.  Hernan was moving toward the west at 2 m.p.h. (3 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.

A low pressure system over the Eastern North Pacific Ocean strengthened on Wednesday night and the U.S. National Hurricane Center designated the system as Tropical Storm Hernan.

The distribution of thunderstorms in Tropical Storm Hernan was asymmetrical.  An upper level trough near the West Coast of the U.S. was producing westerly winds that were blowing toward the top of Hernan’s circulation.  Those winds were causing moderate vertical wind shear.  The moderate vertical wind shear was causing the asymmetrical distribution of thunderstorms in Tropical Storm Hernan.

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

Even though the thunderstorms were in the eastern side of Tropical Storm Hernan, the strongest winds were occurring in the western side of Hernan.  Winds to tropical storm force extended out 40 miles (65 km) in the western side of Hernan’s circulation.  The winds in the eastern side of Tropical Storm Hernan were blowing at less than tropical storm force.

Tropical Storm Hernan will move through an environment that will be unfavorable for intensification during the next 24 hours.  Hernan will move over water where the Sea Surface Temperatures are near 26°C.  However, the upper level trough near the West Coast of the U.S. will continue to cause moderate vertical wind shear.  Tropical Storm Hernan is unlikely to intensify during the next 24 hours because of the vertical wind shear.

Tropical Storm Hernan will move around the southern part of a high pressure system over the Eastern North Pacific Ocean.  The high pressure system will steer Hernan toward the southwest during the next 24 hours.  On its anticipated track, Tropical Storm Hernan will remain far to the west of Baja California.

Elsewhere, Potential Tropical Cyclone One-C moved closer to Hawaii.  At 5:00 a.m. EDT on Thursday the center of Potential Tropical Cyclone One-C was located at latitude 14.8°N and longitude 144.5°W which put the center about 775 miles (1250 km) east-southeast of Hilo,Hawaii.   It 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 1002 mb.

Tropical Storms Hernan and Iselle Form West of Mexico

Tropical Storms Hernan and Iselle formed west of Mexico.  At 11:00 a.m. EDT on Thursday the center of Tropical Storm Hernan was located at latitude 19.1°N and longitude 106.2°W which put it about 95 miles (155 km) south-southwest of Cabo Corrientes, Mexico.  Hernan was moving toward the north-northwest at 5 m.p.h. (8 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 1001 mb.

The circulation around Tropical Storm Hernan was not well organized.  An upper level ridge over the southwestern U.S. and northern Mexico was producing northeasterly winds which were blowing toward the top of Hernan.  Those winds were causing strong vertical wind shear.  As a result of the shear, the stronger thunderstorms were occurring in bands in the southern part of the circulation.  Bands in the other parts of Tropical Storm Hernan consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out 100 miles in the southern half of Hernan.  Winds in the northern half of the circulation were blowing at less than tropical storm force.

Tropical Storm Hernan will move through an environment unfavorable for intensification during the next several days.  Hernan will move over water where the Sea Surface Temperature is near 29°C.  So, there will be plenty of energy in the upper ocean to support intensification.  However, the upper level ridge will continue to cause strong vertical wind shear, which will inhibit potential intensification.  Tropical Storm Hernan is likely to weaken on Friday when it moves over colder water.  Hernan could approach the southern end of Baja California on Friday.

At 11:00 a.m. EDT on Thursday the center of Tropical Storm Iselle was located at latitude 17.0°N and longitude 115.8°W which put it about 560 miles (900 km) southwest of the southern tip of Baja California.  Iselles was moving toward the northeast at 5 m.p.h. (8 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 1001 mb.

The circulation around Tropical Storm Iselle was also not well organized.  It was being sheared by the same upper level ridge that was causing strong vertical wind shear over Tropical Storm Hernan.  Most of the thunderstorms in Iselle were also occurring in the southern half of the circulation.  Tropical storm force winds extended out 100 miles from the center in the southern half of Tropical Storm Iselle.  Iselle will also move through an environment unfavorable for intensification.