Category Archives: Eastern and Central Pacific

TCs between Mexico and Hawaii

Karina Rapidly Intensifies to a Major Hurricane

Hurricane Karina rapidly intensified to a major hurricane on Sunday evening as it moved over the Eastern North Pacific Ocean southwest of Baja California.  At 8:00 p.m. EDT on Sunday the center of Hurricane Karina was located at latitude 17.2°N and longitude 123.4°W which put the center about 960 miles (1545 km) west-southwest of the southern tip of Baja California.  Karina was moving toward the west 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 150 m.p.h. (240 km/h).  The minimum surface pressure was 955 mb.

Hurricane Karina rapidly intensified to a major hurricane on Sunday evening.  The inner end of a rainband wrapped around the center of Karina’s circulation.  A circular eye with a diameter of 25 miles (40 km) formed at the center of Hurricane Karina.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Karina’s circulation.  Storms near the core of Karina generated strong upper level divergence that pumped large amounts of mass away from the hurricane.  The removal of large amounts of mass caused the surface pressure to decrease rapidly.

The inner core of Hurricane Karina was very small.  Winds to hurricane force extended out 15 miles (25 km) from the center of Karina’s circulation.  Winds to tropical storm force extended out 205 miles (335 km) from the center of Hurricane Karina.

Hurricane Karina will move through an environment mostly favorable for intensification during the next 24 hours.  Karina will move over water where the Sea Surface Temperatures are near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  However, there is a mass of drier air just to the west and north of Hurricane Karina.  The drier air will inhibit intensification of Karina, but the drier air probably will not be enough to prevent intensification.  Hurricane Karina is likely to intensify during the next 24 hours.  Karina could continue to intensify rapidly during the next few hours, if the drier air does not get pulled into its circulation.

Hurricane Karina will move around the southern part of a high pressure system that is over the Eastern North Pacific Ocean.  The high pressure system will steer Karina toward the west-northwest during the next 24 hours.  On its anticipated track, Hurricane Karina will move farther away from Baja California.

Elsewhere, Tropical Storm Lowell moved over the Central Pacific Ocean.  At 5:00 p.m. EDT on Sunday the center of Tropical Storm Lowell was located at latitude 13.3°N and longitude 141.8°W which put the center about 985 miles (1585 km) east-southeast Hilo, Hawaii.  Lowell was moving toward the west at 13 m.p.h. (21 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 999 mb.

Karina Strengthens to a Hurricane

Former Tropical Storm Karina strengthened to a hurricane as it moved over the Eastern North Pacific Ocean southwest of Baja California on Saturday night.  At 5:00 a.m. EDT on Sunday the center of Hurricane Karina was located at latitude 17.3°N and longitude 121.1°W which put the center about 820 miles (1325 km) west-southwest of the southern tip of Baja California.  Karina was moving toward the west-northwest at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 980 mb.

Former Tropical Storm Karina strengthened to a hurricane on Saturday night.  The inner end of a rainband wrapped around the western and southern sides of the center of Karina’s circulation.  An eye appeared to be forming at the center of Hurricane Karina.

The distribution of thunderstorms in Hurricane Karina was asymmetrical.  Thunderstorms were mostly occurring in bands in the southern half of Karina’s circulation.  Bands in the northern half of Hurricane Karina consisted primarily of showers and lower clouds.  Storms near the center of Karina generated upper level divergence that pumped mass away from the hurricane.  The removal of mass caused the surface pressure to decrease.

The strongest winds were occurring in the northeastern part of Hurricane Karina.  Winds to hurricane force extended out 25 miles (40 km) in the northeastern quadrant of Karina’s circulation.  Winds to tropical storm force extended out 230 miles (370 km) from the center of Hurricane Karina.

Hurricane Karina will move through an environment mostly favorable for intensification during the next 24 hours.  Karina will move over water where the Sea Surface Temperatures are near 28°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  However, there is a mass of drier air just to the west and north of Hurricane Karina.  The drier air will inhibit intensification of Karina, but the drier air probably will not be enough to prevent intensification.  Hurricane Karina is likely to intensify during the next 24 hours.  Karina could intensify rapidly at times, if the drier air does not get pulled into its circulation.  Karina strengthen to a major hurricane by Monday morning.

Hurricane Karina will move around the southern part of a high pressure system that is over the Eastern North Pacific Ocean.  The high pressure system will steer Karina toward the west-northwest during the next 24 hours.  On its anticipated track, Hurricane Karina will move farther away from Baja California.

Elsewhere over the Eastern North Pacific Ocean, Tropical Storm Lowell was moving west toward the Central Pacific.  At 5:00 a.m. EDT on Sunday the center of Tropical Storm Lowell was located at latitude 13.2°N and longitude 139.1°W which put the center about 1150 miles (1850 km) east-southeast Hilo, Hawaii.  Lowell was moving toward the west at 10 m.p.h. (16 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 1000 mb.

Tropical Storms Karina and Lowell Form over Eastern North Pacific

Tropical Storms Karina and Lowell formed over the Eastern North Pacific Ocean on Thursday afternoon.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Karina was located at latitude 11.1°N and longitude 111.9°W which put the center about 825 miles (1330 km) south of the southern tip of Baja California.  Karina was moving toward the west-northwest at 13 m.p.h. (21 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.

Two low pressure systems over the Eastern North Pacific Ocean strengthened on Thursday afternoon and the U.S. National Hurricane Center designated the systems as Tropical Storm Karina and Tropical Storm Lowell.

Thunderstorms were developing in bands in the southern and eastern parts of Tropical Storm Karina.  Bands in the northwestern part of Karina’s circulation consisted primarily of showers and lower clouds.  Storms near the center of Karina 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 northern part of Tropical Storm Karina.  Winds to tropical storm force extended out 205 miles (335 km) in the northern side of Karina’s circulation.  The winds in the southern side of Tropical Storm Karina were blowing at less than tropical storm force.

Tropical Storm Karina will move through an environment favorable for intensification during the next 24 hours.  Karina will move over water where the Sea Surface Temperatures are near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Storm Karina will intensify during the next 24 hours.  Karina could strengthen to a hurricane by Saturday morning.

Tropical Storm Karina will move around the southwestern part of a high pressure system that is centered over the Southwest U.S.  The high pressure system will steer Karina toward the northwest during the next 24 hours.  On its anticipated track, Tropical Storm Karina will move far to the southwest of Baja California.

At 5:00 p.m. EDT on Thursday the center of Tropical Storm Lowell was located at latitude 11.3°N and longitude 133.8°W which put the center about 1765 miles (2840 km) west-southwest of the southern tip of Baja California.  Lowell was moving toward the east-northeast at 5 m.p.h. (8 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.

Tropical Storm Lowell is forecast to move west toward the Central North Pacific Ocean and to strengthen to a hurricane during the weekend.

Tropical Storm Iselle Weakens

Tropical Storm Iselle weakened on Tuesday as it moved over the Eastern North Pacific Ocean west of Baja California.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Iselle was located at latitude 21.3°N and longitude 122.5°W which put the center about 815 miles (1310 km) west of the southern tip of Baja California.  Iselle was moving toward the west-northwest 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 996 mb.

Tropical Storm Iselle weakened on Tuesday.  An upper level trough west of the West Coast of the U.S. was producing southwesterly winds that were blowing toward the top of Iselle’s circulation.  Those winds were causing moderate vertical wind shear.  The vertical wind shear was causing Tropical Storm Iselle to weaken.

The vertical wind shear was also causing the distribution of thunderstorms in Tropical Storm Iselle to be asymmetrical.  Thunderstorms were occurring in bands in the eastern side of Iselle’s circulation.  Bands in the western side of Tropical Storm Iselle consisted primarily of showers and lower clouds.  Storms near the center of Iselle generated upper level divergence that pumped mass away to the northeast of the tropical storm.  The removal of mass in the upper levels was less than the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure increased on Tuesday.

The effects of the vertical wind shear also caused the distribution of wind speeds in Tropical Storm Iselle to be asymmetrical.  Winds to tropical storm force extended out 230 miles (370 km) in the eastern side of Iselle’s circulation.  Winds to tropical storm force extended out 140 miles (220 km) in the western side of Tropical Storm Iselle.

Tropical Storm Iselle will move through an environment that will be unfavorable for intensification during the next 24 hours.  Iselle will move over water where the Sea Surface Temperatures are near 26°C.  It will continue to move under the southern part of an upper level trough that is west of the West Coast of the U.S.  The upper level trough will continue to produce southwesterly winds that will blow toward the top of Iselle’s circulation.  Those winds will continue to cause moderate vertical wind shear.  In addition, Iselle will move into a mass of drier air that is west of Baja California.  Tropical Storm Iselle will  continue to weaken on Wednesday because of the effects of the vertical wind shear and the drier air.

Tropical Storm Iselle will move around the southwestern part of a high pressure system that is over the Eastern North Pacific Ocean.  The high pressure system will steer Iselle toward the west-northwest during the next 24 hours.  On its anticipate track, Tropical Storm Iselle will move farther away from Baja California.

Elsewhere, Tropical Storm Lala continued to weaken slowly far to the northwest of Hawaii.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Lala was located at latitude 35.2°N and longitude 177.6°W which put the center about 470 miles (760 km) north of Kure Atoll.  Lala was moving toward the west-northwest at 6 m.p.h. (10 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 995 mb.

Tropical Storm Iselle Spins Southwest of Baja California

Tropical Storm Iselle was spinning southwest of Baja California on Monday night.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Iselle was located at latitude 20.1°N and longitude 118.6°W which put the center about 590 miles (950 km) west-southwest of the southern tip of Baja California.  Iselle was moving toward the northwest at 15 m.p.h. (24 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 988 mb.

Tropical Storm Iselle strengthened on Monday.  More thunderstorms developed near the center of Iselle’s circulation.  Bands of showers and thunderstorms were also revolving around the center of Tropical Storm Iselle.  Storms near the center of Iselle generated upper level divergence that pumped mass away from the tropical storm.  The removal of mass caused the surface pressure to decrease.

Wind to tropical storm force extended out 195 miles (315 km) from the center of Tropical Storm Iselle.

Tropical Storm Iselle will move through an environment that will become unfavorable for intensification during the next 24 hours.  Iselle will move over water where the Sea Surface Temperatures are near 27°C.  It will move under the southern part of an upper level trough that is west of the West Coast of the U.S  The upper level trough will produce southwesterly winds that will blow toward the top of Iselle’s circulation.  Those winds will cause the vertical wind shear to increase on Tuesday.  In addition, Iselle will move into a mass of drier air that is west of Baja California.  Tropical Storm Iselle is likely to start to weaken on Tuesday because of the effects of the increased vertical wind shear and the drier air.

Tropical Storm Iselle will move around the southwestern part of a high pressure system that is over the Eastern North Pacific Ocean.  The high pressure system will steer Iselle toward the west-northwest during the next 24 hours.  On its anticipate track, Tropical Storm Iselle will move farther away from Baja California.

Elsewhere, former Tropical Storm Moke weakened to a tropical depression south of Hawaii and Tropical Storm Lala weakened gradually far to the northwest of Hawaii.

At 11:00 p.m. EDT on Monday the center of Tropical Depression Moke was located at latitude 16.0°N and longitude 163.0°W which put the center about 435 miles (695 km) east of Johnston Island.  Moke was moving toward the west at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1005 mb.

At 11:00 p.m. EDT on Monday the center of Tropical Storm Lala was located at latitude 34.3°N and longitude 175.6°W which put the center about 435 miles (705 km) north-northeast of Kure Atoll.  Lala was moving toward the northwest at 6 m.p.h. (10 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 992 mb.

Tropical Storm Iselle Forms South of Baja California

Tropical Storm Iselle formed over the Eastern North Pacific Ocean south of Baja California on Sunday morning.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Iselle was located at latitude 15.3°N and longitude 114.2°W which put the center about 595 miles (955 km) south-southwest of the southern tip of Baja California.  Iselle was moving toward the west-northwest at 12 m.p.h. (19 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 1003 mb.

A low pressure system over the Eastern North Pacific Ocean south of Baja California strengthened on Sunday morning and the U.S. National Hurricane Center designated the system as Tropical Storm Iselle.

The distribution of thunderstorms in Tropical Storm Iselle was asymmetrical.  Thunderstorms were occurring in bands in the southern part of Iselle’s circulation.  Bands in the northern side of Tropical Storm Iselle consisted primarily of showers and lower clouds.  Storms near the center of Iselle generated upper level divergence that pumped mass away to the south and west of the tropical storm.  The removal of mass caused the surface pressure to decrease.

Wind to tropical storm force extended out 105 miles (165 km) from the center of Tropical Storm Iselle.

Tropical Storm Iselle will move through an environment that will be somewhat favorable for intensification during the next 24 hours.  Iselle will move over water where the Sea Surface Temperatures are near 29°C  It will move under the southeastern part of an upper level ridge that is south of Baja California.  The upper level ridge will produce northeasterly winds that will blow toward the top of Iselle’s circulation.  Those winds will cause moderate vertical wind shear.  The moderate vertical wind shear will inhibit intensification, but the wind shear may not be enough to prevent intensification.  Tropical Storm Estelle could intensify during the next 24 hours.

Tropical Storm Iselle will move around the southwestern part of a high pressure system that is over the Eastern North Pacific Ocean.  The high pressure system will steer Iselle toward the northwest during the next 24 hours.  On its anticipate track, Tropical Storm Iselle will remain far to the southwest of Baja California.

Elsewhere, Tropical Storm Moke was passing south of the Big Island of Hawaii and Tropical Storm Lala was spinning far to the northwest of Hawaii.

At 11:00 a.m. EDT on Sunday the center of Tropical Storm Moke was located at latitude 15.2°N and longitude 155.0°W which put the center about 310 miles (500 km) south of Hilo, Hawaii. Moke was moving toward the west at 15 m.p.h. (24 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 1002 mb.

At 11:00 a.m. EDT on Sunday the center of Tropical Storm Lala was located at latitude 32.1°N and longitude 173.9°W which put the center about 365 miles (590 km) northeast of Kure Atoll.  Lala was moving toward the west-northwest at 5 m.p.h. (8 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 988 mb.

Tropical Storm Moke Prompts Flood Watches for Hawaii

A potential chance of heavy rain caused by Tropical Storm Moke prompted the U.S. National Weather Service to issue a Flood Watch for portions of the Big Island of Hawaii on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Moke was located at latitude 14.9°N and longitude 151.1°W which put the center about 425 miles (680 km) southeast of Hilo, Hawaii.  Moke was moving toward the west-northwest at 12 m.p.h. (19 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 996 mb.

Flood Watches are in effect for the windward and southeastern parts of the Big Island of Hawaii.

Tropical Storm Moke strengthened a little on Saturday.  Even though Moke was a little stronger, the distribution of thunderstorms was still asymmetrical.  Thunderstorms were occurring in bands in the northern side of Moke’s circulation.  Bands in the southern side of Tropical Storm Moke consisted primarily of showers and lower clouds.

An upper level trough that was just east of Hawaii was continuing to produce southwesterly winds that were blowing toward the top of Tropical Storm Moke.  Those winds were causing moderate vertical wind shear.  The vertical wind shear was causing the asymmetrical distribution of thunderstorms.

The distribution of wind speeds in Tropical Storm Moke was also asymmetrical.  Winds to tropical storm force extended out 115 miles (185 km) in the northern side of Moke’s circulation. Winds to tropical storm force only extended out 45 miles (75 km) in the southern half of Tropical Storm Moke.

Tropical Storm Moke will move through an environment that will become unfavorable for intensification during the next 24 hours.  Moke will move over water where the Sea Surface Temperatures are near 28°C.  However, the upper level trough just east of Hawaii will continue to cause moderate vertical wind shear.  In addition, Tropical Storm Moke will move into a mass of drier air that is south of Hawaii.  The vertical wind shear and the drier air are likely to cause Tropical Storm Moke to start to weaken on Sunday.

Tropical Storm Moke will move around the southern side of a high pressure system that is north of Hawaii.  The high pressure system will steer Moke toward the west-northwest during the next 24 hours.  On its anticipated track, Tropical Storm Moke will start to pass south of Hawaii on Sunday.

Bands in the northern part of Tropical Storm Moke could bring gusty winds to the Big Island of Hawaii.  The strongest winds will occur at higher elevations.  Those same bands could also drop heavy rain over parts of the Big Island.  Heavy rain would likely cause flash floods because the ground is still saturated from rain caused by Hurricane Lala.

Flood Watches are in effect for the windward and southeastern parts of the Big Island of Hawaii.

Elsewhere over the Central North Pacific Ocean, Hurricane Lala was weakening gradually as it moved far to the northwest of Hawaii.  At 5:00 p.m. EDT on Saturday the center of Hurricane Lala was located at latitude 31.0°N and longitude 172.7°W which put the center about 380 miles (614 km) east-northeast of Kure Atoll.  Lala was moving toward the northwest 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 981 mb.

Depression Strengthens to Tropical Storm Moke

Former Tropical Depression Two-C strengthened to Tropical Storm Moke southeast of Hawaii on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Moke was located at latitude 13.9°N and longitude 147.2°W which put the center about 660 miles (1060 km) southeast of Hilo, Hawaii.  Moke was moving toward the west-northwest at 9 m.p.h. (15 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 1002 mb.

A U.S. Air Force Reserve Hurricane Hunter reconnaissance plane found that former Tropical Depression Two-C had strengthened on Friday and the U.S. National Hurricane Center designated the system as Tropical Storm Moke.

Even though Former Tropical Depression Two-C strengthened on Friday, the distribution of thunderstorms in Tropical Storm Moke was asymmetrical.  Thunderstorms were occurring in bands in the northern side of Moke’s circulation.  Bands in the southern side of Tropical Storm Moke consisted primarily of showers and lower clouds.

An upper level trough that was just east of Hawaii was producing southwesterly winds that were blowing toward the top of Tropical Storm Moke.  Those winds were causing moderate vertical wind shear.  The vertical wind shear was causing the asymmetrical distribution of thunderstorms.

The distribution of wind speeds in Tropical Storm Moke was also asymmetrical.  Winds to tropical storm force extended out 65 miles (105 km) in the northern side of Moke’s circulation.  The winds in the southern half of Tropical Storm Moke were blowing at less than tropical storm force.

Tropical Storm Moke will move through an environment somewhat favorable for intensification during the next 24 hours.  Moke will move over water where the Sea Surface Temperatures are near 28°C.  However, the upper level trough just east of Hawaii will continue to 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 Moke could continue to intensify during the next 24 hours.

Tropical Storm Moke will move around the southern side of a high pressure system that is north of Hawaii.  The high pressure system will steer Moke toward the west-northwest during the next 24 hours.  On its anticipated track, Tropical Storm Moke will pass south of Hawaii during the weekend.

Elsewhere over the Central North Pacific Ocean, Hurricane Lala moved north of the Papahanaumokuakea Marine National Monument.   At 5:00 p.m. EDT on Friday the center of Hurricane Lala was located at latitude 28.6°N and longitude 170.4°W which put the center about 230 miles (420 km) north of Maro Reef.  Lala was moving toward the north-northeast at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 105 m.p.h. (165 km/h).  The minimum surface pressure was 974 mb.

Tropical Depression Forms East-southeast of Hawaii

Tropical Depression Two-C formed east-southeast of Hawaii on Thursday morning.  At 11:00 a.m. EDT on Thursday the center of Tropical Depression Two-C was located at latitude 11.9°N and longitude 143.1°W which put the center about 960 miles (1545 km) east-southeast of Hilo, Hawaii.  The tropical depression was moving toward the west-northwest at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1006 mb.

A low pressure system over the Central North Pacific Ocean east-southeast of Hawaii strengthened on Thursday morning and the U.S. National Hurricane Center designated the system as Tropical Depression Two-C.

The distribution of thunderstorms in Tropical Depression Two-C was asymmetrical.  Thunderstorms were occurring in bands in the western side of Tropical Depression Two-C.  Bands in the eastern side of the tropical depression consisted primarily of showers and lower clouds.  Storms near the center of circulation generated upper level divergence that pumped mass away to the west of the tropical depression.  The removal of mass caused the surface pressure to start to decrease.

Tropical Depression Two-C will move through an environment that will be somewhat favorable for intensification during the next 24 hours.  The tropical depression will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the southern part of an upper level ridge that is over the Eastern and Central North Pacific Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Tropical Depression Two-C.  Those winds will cause moderate vertical wind shear.  The vertical wind shear will inhibit intensification but the wind shear will probably not be enough to prevent intensification.  Tropical Depression Two-C is likely to intensify slowly during the next 24 hours.

Tropical Depression Two-C will move around the southern side of a high pressure system that is over the Central North Pacific Ocean.  The high pressure system will steer the tropical depression toward the west-northwest during the next 24 hours.  On its anticipated track, Tropical Depression Two-C will move closer to Hawaii.

Elsewhere over the Central Pacific Ocean, Hurricane Lala was nearing the Papahanaumokuakea Marine National Monument.  At 11:00 a.m. EDT on Thursday the center of Hurricane Lala was located at latitude 24.2°N and longitude 172.2°W which put the center about 175 miles (280 km) southeast of Lisianski Island.  Lala was moving toward the north-northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 969 mb.

A Hurricane Warning is in effect for the Papahanaumokuakea Marine National Monument from Lisianski Island to Maro Reef.

A Tropical Storm Warning is in effect for the Papahanaumokuakea Marine National Monument from Maro Reef to French Frigate Shoals.

Hurricane Lala Moves North

Hurricane Lala moved north toward the Papahanaumokuakea Marine National Monument on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Hurricane Lala was located at latitude 22.2°N and longitude 171.0°W which put the center about 330 miles (530 km) southeast of Lisianski Island.  Lala was moving toward the north-northwest at 9 m.p.h. (15 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. (220 km/h).  The minimum surface pressure was 955 mb.

A Hurricane Warning is in effect for the Papahanaumokuakea Marine National Monument from Lisianski Island to Maro Reef.

A Tropical Storm Warning is in effect for the Papahanaumokuakea Marine National Monument from Maro Reef to French Frigate Shoals.

Hurricane Lala maintained its intensity for much of Wednesday.  Lala was exhibiting signs of starting to weaken slowly on Wednesday afternoon.  An upper level trough that was south of the Aleutian Islands was producing southwesterly winds that were blowing toward the top of Lala’s circulation.  Those winds were causing the vertical wind shear to increase.  The increase in vertical wind shear was likely the cause of the weakening of Hurricane Lala.

There was still a small circular eye at the center of Hurricane Lala.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Hurricane Lala.  Storms near the core of Lala generated upper level divergence that pumped mass away from the hurricane.  The removal of mass in the upper levels was slightly less than the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure started to increase slowly on Wednesday afternoon.

The distribution of wind speeds in Hurricane Lala was still fairly symmetrical on Wednesday afternoon.  Winds to hurricane force extended out 30 miles (50 km) from the center of Lala’s circulation.  Winds to tropical storm force extended out 115 miles (185 km) from the center of Hurricane Lala.

The Hurricane Intensity Index (HII) for Hurricane Lala is 22.1.  The Hurricane Size Index (HSI) is 11.0 and the Hurricane Wind intensity Size Index (HWISI) is 33.1.  Hurricane Lala is similar in size and intensity to Hurricane Dennis when Dennis hit Northwest Florida in 2005.

Hurricane Lala will move through an environment that will become unfavorable for intensification during the next 24 hours.  Lala will move over water where the Sea Surface Temperatures are near 27°C.  However, the upper level trough that is south of Aleutian Islands will continue to cause the vertical wind shear to increase on Thursday.  Hurricane Lala will continue to weaken during the next 24 hours.

The upper level trough south of the Aleutian Islands will steer Hurricane Lala toward the north on Thursday.  On its anticipated track, Hurricane Lala will reach the Papahanaumokuakea Marine National Monument on Thursday night.

Hurricane Lala will bring strong winds and heavy rain to parts of the Papahanaumokuakea Marine National Monument.  The winds around Hurricane Lala will also cause high surf conditions.