Tag Archives: EP12

Tropical Storm Lorena Forms, Watch Issued for Mexico

Tropical Storm Lorena formed south of Mexico on Tuesday and a Tropical Storm Watch was issued for a portion of the coast.  At 2:00 p.m. EDT on Tuesday the center of Tropical Storm Lorena was located at latitude 13.9°N and longitude 100.4°W which put it about 275 miles (440 km) south-southeast of Zihuatanejo, Mexico.  Lorena was moving toward the northwest 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 1004 mb.

A Tropical Storm Watch was issued for the portion of the coast from Zihuatanejo to Cabo Corrientes, Mexico.

A distinct low level center of circulation formed in a cluster of thunderstorms south of Mexico on Tuesday and the National Hurricane Center designated the system as Tropical Storm Lorena.  The circulation around Lorena was still organizing.  Bands of showers and thunderstorms were curling around the western side of the center of circulation.  Bands in the eastern half of the circulation consisted primarily of showers and lower clouds.  An upper level ridge over Mexico was producing northeasterly winds which were blowing toward the top of the circulation.  Those winds were causing moderate vertical wind shear and they may have been the reason why the bands were stronger in the western half of  Tropical Storm Lorena.

Tropical Storm Lorena will move through an environment favorable for intensification during the next several days.  Lorena will move over water where the Sea Surface Temperature is near 30°C.  The upper level ridge will continue to cause some vertical wind shear, which will inhibit intensification.  The shear is likely to slow the rate at which Tropical Storm Lorena intensifies.  Lorena could move near the west coast of Mexico.  If the center moves near the coast, then the circulation could draw some drier air into the tropical storm.  The drier would likely cause Tropical Storm Lorena to weaken.  If the center of Lorena remains west of the coast of Mexico, then it could strengthen into a hurricane later this week.

A ridge over Mexico will steer Tropical Storm Lorena toward the northwest during the next few days.  On its anticipated track the center of Tropical Storm Lorena could be near the west coast of Mexico by Wednesday night.  That is the reason the government of Mexico issued a Tropical Storm Watch for that portion of the coast.  Lorena could approach Baja California in four or five days.

Elsewhere over the Eastern North Pacific Ocean, Hurricane Kiko was weakening slowly well east of Hawaii and Tropical Depression Fourteen-E developed south of Baja California.  At 11:00 a.m. EDT on Tuesday the center of Hurricane Kiko was located at latitude 17.0°N and longitude 125.0°W which put it about 1060 miles (1705 km) west-southwest of the southern tip of Baja California.  Kiko was moving toward the west-southwest at 5 m.p.h. (8 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 987 mb.

At 11:00 a.m. EDT on Tuesday the center of Tropical Depression Fourteen-E was located at latitude 11.9°N and longitude 108.2°W which put it about 720 miles (1235 km) south of the southern tip of Baja California.  it was moving toward the north-northwest at 9 m.p.h. (15 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 1008 mb.

Tropical Storm Akoni Develops Southeast of Hawaii

Tropical Storm Akoni developed southeast of Hawaii on Thursday.  At 7:00 p.m. EDT on Thursday the center of Tropical Storm Akoni was located at latitude 12.2°N and longitude 144.8°W which put it about 855 miles (1380 km) southeast of Hilo, Hawaii.  Akoni was moving toward the west at 7 m.p.h. (11 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.

More thunderstorms developed near an area of low pressure southeast of Hawaii on Thursday and the Central Pacific Hurricane Center designated it as Tropical Storm Akoni when satellites indicated there were winds to tropical storm force.  The circulation around Tropical Storm Akoni was still organizing.  Bands of showers and thunderstorms were forming.  The strongest rainbands were in the southern half of the circulation.  Bands in the northern half of the circulation were not as strong.  Winds to tropical storm force extended out about 70 miles (110 km) from the center of circulation.

Tropical Storm Akoni will move through an environment favorable for intensification during the next several days.  Akoni will move over water where the Sea Surface Temperature is near 28°C.  It will move southeast of an upper level trough northeast of Hawaii.  The trough will produce southwesterly winds which will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification.  Tropical Storm Akoni is forecast to strengthen gradually during the next several days.

Tropical Storm Akoni will move south of a subtropical high pressure system over the eastern and central Pacific Ocean.  The high will steer Akoni toward the west-northwest.  On its anticipated track Tropical Storm Akoni will be south of Hawaii on Sunday.

Elsewhere, Hurricane Juliette was weakening slowly southwest of Baja California.  At 5:00 p.m. EDT on Thursday the center of Hurricane Juliette was located at latitude 21.3°N and 120.8°W which put it about 870 miles (1380 km) west-southwest of the southern tip of Baja California.  Juliette was moving toward the northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 980 mb.

Hurricane Hector Passes South of Hawaii

Powerful Hurricane Hector passed south of Hawaii on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Hurricane Hector was located at latitude 16.7°N and longitude 156.8°W which put it about 325 miles (525 km) south-southeast of Honolulu, Hawaii.  Hector was moving toward the west at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 135 m.p.h. (220 km/h).  The minimum surface pressure was 959 mb.

The circulation of Hurricane Hector remained circular and symmetrical.  Information from radar and satellites indicated that Hurricane Hector had a double eyewall structure.  There was a small inner eye surrounded by an inner eyewall.  The inner eyewall was thin and it appeared to be weakening.  A clear area, sometimes called a moat, surrounded the inner eyewall.  A second thicker eyewall surrounded the moat.  Several shorter bands of of showers and thunderstorms were revolving around the core of Hector.  The circulation of Hurricane Hector was relatively small.  Winds to hurricane force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force only extended out about 95 miles (155 km) from the center.

Hurricane Hector exhibited a structure that is sometimes called an annular hurricane.  Annular hurricanes often achieve an equilibrium with their environment which can persist for days if there is not much wind shear.  Hector will move over water where the Sea Surface Temperature is between 27°C and 28°C.  It will move through a region where there is little vertical wind shear.  Hurricane Hector will remain a strong hurricane and it could strengthen during the next 24 to 48 hours, if the inner eyewall dissipates completely.

Hurricane Hector will move south of the subtropical high pressure system over the Central Pacific.  The high will steer Hector toward the west for several more days.  On its anticipated track Hurricane Hector will remain south of Hawaii.

Elsewhere over the Eastern North Pacific Ocean, Hurricane John weakened west of Baja California and Tropical Storm Kristy exhibited little change on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Hurricane John was located at latitude 23.1°N and longitude 114.4°W which put it about 285 miles (460 km) west of the southern tip of Baja California.  John was moving toward the northwest at 16 m.p.h. (26 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 983 mb.

At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Kristy was located at latitude 15.3°N and longitude 130.0°W which put it about 1410 miles (2220 km) west-southwest of the southern tip of Baja California.  Kristy was moving toward the northwest at 7 m.p.h. (11 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.

Hurricane John Absorbs Ileana, Tropical Storm Kristy Forms

The much stronger and larger circulation of Hurricane John absorbed the smaller and weaker Tropical Storm Ileana south of Baja California on Tuesday morning, while Tropical Storm Kristy formed farther west over the Eastern North Pacific Ocean.  At 5:00 p.m. EDT on Tuesday the center of Hurricane John was located at latitude 18.7°N and longitude 110.5°W which put it about 295 miles (470 km) south of the southern tip of Baja California.  John was moving toward the northwest at 10 m.p.h. (17 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 969 mb.

The circulation of Hurricane John is well organized.  A circular eye is at the center of circulation.  A ring of stronger thunderstorms wraps around the eye.  The strongest storms are in the eastern half of the ring and that is where the strongest winds are occurring.  Several bands of showers and thunderstorms are revolving around the core of Hurricane John.  The strongest bands are south and east of the center of circulation.  The bands north and west of the center are weaker and there is cooler water in that area.  Storms around the core of the circulation are generating strong upper level divergence which is pumping mass away from the hurricane.

Hurricane John will move through an environment favorable for intensification on Wednesday.  John will move over water where the Sea Surface Temperature is near 29°C.  It will move through an area where the upper level winds are weak.  Hurricane John could intensify on lWednesday and it has a chance to strengthen into a major hurricane.  John will start to move over cooler water in 24 to 36 hours and it will start to weaken when that happens.

Hurricane John will move around the western side of a ridge in the middle troposphere.  The ridge will steer John toward the northwest during the next day or two.  On its anticipated track the core of Hurricane John will pass west of Baja California.  Rainbands north of the center of Hurricane John could drop locally heavy rain over parts of Baja California and there will be a risk of flash floods.  Hurricane John could push higher surf along the west coast of Baja California toward southern California.

Elsewhere over the Eastern North Pacific, Tropical Storm Kristy formed southwest of Hurricane John on Tuesday morning.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Kristy was located at latitude 13.7°N and longitude 127.1°W which put it about 1290 miles (2080 km) west-southwest of the southern tip of Baja California.  Kristy was moving toward the west at 13 m.p.h. (20 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.  There is much uncertainty about whether or not the circulation of Tropical Storm Kristy will be affected by the circulation of Hurricane John.

Powerful Hurricane Hector Approaches Central Pacific, Ileana Forms South of Mexico

Powerful Hurricane Hector approached the Central Pacific Ocean on Sunday while Tropical Storm Ileana and Tropical Depression Twelve-E formed south of Mexico.  The government of Mexico issued a Tropical Storm Watch for a portion of the coast because of the potential impacts of Tropical Storm Ileana.  At 8:00 p.m. EDT on Sunday the center of Hurricane Hector was located at latitude 14.5°N and longitude 138.6°W which put it about 1170 miles (1885 km) east-southeast of South Point, Hawaii.  Hector was moving toward the west at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 140 m.p.h. (220 km/h) and there were wind gusts to 165 m.p.h. (270 km/h).  The minimum surface pressure was 947 mb.

The circulation of Hurricane Hector was very well organized.  There was a circular eye with a diameter of 18 miles (29 km) at the center of circulation.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of Hurricane Hector.  Storms in the core of Hector were generating strong upper level divergence which was pumping mass away from the hurricane.

The circulation of Hurricane Hector remained compact.  Winds to hurricane force extended out about 30 miles (50 km) from the center of circulation.  Winds to tropical storm force extended out about 100 miles (160 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Hector was 28.3.  The Hurricane Size Index (HSI) was 9,9 and The Hurricane Wind Intensity Size Index (HWISI) was 38.2.

Hurricane Hector will move through an environment capable of supporting a strong hurricane during the next day or two.  It will move over water where the Sea Surface Temperature is near 27°C and 28°C.  Hector will move through an area where the upper level winds are weak and there will be little vertical wind shear.  An eyewall replacement cycle could occur if a rainband wraps around the existing eye and eyewall.  It would cause fluctuations in the intensity of Hurricane Hector.

Hurricane Hector will move south of the subtropical high pressure system over the Eastern North Pacific Ocean.  The high will steer Hurricane Hector toward the west during the next several days.  On its anticipated track Hurricane Hector will be southeast of Hawaii in about three days.

Tropical Storm Ileana developed south of Mexico on Sunday.  The government of Mexico issued a Tropical Storm Watch for the portion of the coast from Lazaro Cardenas to Cabo Corrientes.  At 8:00 p.m. EDT on Sunday the center of Tropical Storm Ileana was located at latitude 13.9°N and longitude 98.9°W which put it about 210 miles (335 km) south-southeast of Acapulco, Mexico.  Ileana 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 1000 mb.

Tropical Depression Twelve-E formed west of Tropical Storm Ileana on Sunday.  At 5:00 p.m. EDT on Sunday the center of Tropical Depression Twelve-E was located at latitude 14.6°N and longitude 105.8°W which put it about 320 miles (515 km) south-southwest of Manzanillo, Mexico.  It was moving toward the northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1006 mb.

There is uncertainty about the future interaction of Tropical Storm Ileana and Tropical Depression Twelve-E.  The circulation of Tropical Depression Twelve-E is much larger than the circulation of Tropical Storm Ileana.  In addition, upper level divergence form the depression could cause vertical wind shear over Tropical Storm Ileana.  In one possible scenario Tropical Storm Ileana moves toward Tropical Depression Twelve-E and it is absorbed by the larger circulation.  Another possibility is that Tropical Storm Ileana moves around the eastern periphery of the circulation of the tropical depression,  The second scenario would bring Tropical Storm Ileana close to the west coast of Mexico which is why the Tropical Storm Watch was issued.

Tropical Storm Jova Develops South of Baja California

A center of circulation developed within the remnants of former Hurricane Franklin on Friday and the National Hurricane Center designated the low pressure system as Tropical Storm Jova.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Jova was located at latitude 19.3°N and longitude 109.8°W which put it 250 miles (400 km) south of the southern tip of Baja California.  Jova was moving toward the west-northwest at 14 m.p.h. (22 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 1003 mb.

The surface center of former Hurricane Franklin was disrupted as it passed over the mountains in Mexico.  However, the middle and upper portions of the circulation crossed the mountains relatively intact.  When the upper parts of the former hurricane emerged over the Eastern North Pacific Ocean, it took nearly a day for the vertical transfer of kinetic energy to spin up a new surface circulation.  Eventually a new surface circulation developed and the National Hurricane Center (NHC) classified the system as Tropical Storm Jova.  Established protocol is that when NHC ceases issuing an advisories on a tropical cyclone, the system is given a new name if it redevelops in a different basin.

The circulation of Tropical Storm Jova is broad, but winds to tropical storm force are occurring primarily in the northeastern quadrant of the circulation.  Most of the thunderstorms are occurring in a band that wraps around the western and southern sides of the center of circulation.  There are fewer thunderstorms in the eastern and northern sides of Tropical Storm Jova,  There is a broad counterclockwise circulation and a distinct center, but the horizontal structure is not well organized.

Tropical Storm Jova will be moving through an environment favorable for intensification during the next 24 hours.  Jova will move over water where the Sea Surface Temperature is near 30°C.  An upper lever ridge over northern Mexico is producing easterly winds which are blowing toward the top of the tropical storm.  Those winds are generating vertical wind shear.  The shear is moderate and it will inhibit intensification.  Tropical Storm is likely to intensify during the next 24 hours, but the broad circulation and vertical wind shear will limit the intensification.  In a day or two Tropical Storm Jova will move over cooler Sea Surface Temperatures and it will start to weaken.

A ridge in the middle levels is steering Tropical Storm Jova toward the west-northwest.  The ridge is expected to steer Tropical Storm Jova toward the west during the next several days.  On its anticipated track Tropical Storm Jova will move farther west of Mexico.

Tropical Storm Kay Forms South of Baja California

A distinct center of circulation consolidated within a cluster of thunderstorms south of Baja California and the National Hurricane Center designated the system as Tropical Storm Kay.  At 5:00 a.m. EDT on Friday the center of Tropical Storm Kay was located at latitude 18.4°N and longitude 110.9°W which put it about 315 miles (510 km) south-southwest of the southern tip of Baja California.  Kay was moving toward the northwest at 7 m.p.h. (11 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 1005 mb.

The circulation of Tropical Storm Kay is only moderately well organized.  Most of the stronger thunderstorms are occurring in a band that wraps around the western side of the circulation.  There are also scattered thunderstorms in broken bands around the tropical storm, but much of the convection is occurring in the western half of Kay.  The thunderstorms in the primary rainband are generating some upper level divergence which is moving air to the west of the Tropical Storm Kay.

Tropical Storm Kay is moving through an environment that is marginally favorable for intensification in the short term.  Kay is moving over water where the Sea Surface Temperature (SST) is near 29°C.  An upper level ridge to the north of Kay is generating northeasterly winds which are blowing across the top of the tropical storm.  The moderate vertical wind shear is inhibiting intensification and it is also contributing to the asymmetrical distribution of thunderstorms.  The effect of the warm SSTs could allow for some additional intensification during the next 24 hours.  Tropical Storm Kay will be moving over cooler SSTs during the weekend and the effect of the effect of the cooler water with less energy will weaken the storm.

Tropical Storm Kay is moving around the western end of a subtropical ridge and that is steering the storm toward the northwest.  That general motion is expected to continue for another 24 to 48 hours.  When Tropical Storm Kay moves over cooler SSTs, the thunderstorms will weaken and the circulation will become shallower.  The shallower circulation will be steered by the winds closer to the surface, which are expected to turn Tropical Storm Kay more toward the west in a couple of days.  On its anticipated track Tropical Storm Kay will pass west of Baja California.