Category Archives: Eastern and Central Pacific

TCs between Mexico and Hawaii

Hector Strengthens Into a Major Hurricane

Hurricane Hector strengthened to Category 3 on the Saffir-Simpson Scale on Friday night which made it a major hurricane.  At 11:00 p.m. EDT on Friday the center of Hurricane Hector was located at latitude 14.2°N and longitude 130.9°W which put it about 1640 miles (2640 km) east of Hilo, Hawaii.  Hector was moving toward the west at 12 m.p.h. (19 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. (225 km/h).  The minimum surface pressure was 967 mb.

Hurricane Hector strengthened on Friday night despite having a double eyewall structure.  There was a small inner eye surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  A clear ring sometimes called a moat surrounded the inner eyewall.  The moat was surrounded by an outer eyewall that consisted of showers and thunderstorms.  Several other bands of showers and thunderstorms were revolving around the concentric eyewalls.  Thunderstorms in the core of Hurricane Hector were generating strong upper level divergence which was pumping mass away from the hurricane in all directions.

The circulation of Hurricane Hector was small.  Winds to hurricane force only extended out about 20 miles (30 km) from the center of circulation.  Winds to tropical storm force only extended out about 70 miles (110 km) from the center.

Hurricane Hector will move through an environment favorable for intensification during the weekend.  Hector will move over water where the Sea Surface Temperature is between 27°C and 28°C.  It will move through an area where the upper level winds are weak.  However, the existence of concentric eyewalls means that an eyewall replacement cycle will occur at some time in the future.  The eyewall replacement will cause Hurricane Hector to weaken when the inner eyewall dissipates and the strongest winds are found in the outer eyewall.  Hector could begin to intensify again if the outer eyewall begins to contract closer to the center of circulation.

Hurricane Hector will move south of the subtropical high pressure system over the Eastern North Pacific Ocean and the high will steer Hector westward during the next few days.  On its anticipated track Hurricane Hector could be southeast of Hawaii in four or five days.

Hector Rapidly Intensifies Into a Hurricane

Former Tropical Storm Hector rapidly intensified a hurricane on Thursday morning.  At 11:00 a.m. EDT on Thursday the center of Hurricane Hector was located at latitude 14.2°N and longitude 124.6°W which put it about 1135 miles (1825 km) west-southwest of the southern tip of Baja California.  Hector was moving toward the west at 14 m.p.h. (22 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 987 mb.

The circulation of Hurricane Hector rapidly became more organized on Thursday morning.  A band of showers and thunderstorms wrapped tightly around the center of circulation.  A small eye appeared on satellite images at the center of Hurricane Hector.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Several other bands of showers and thunderstorms were revolving around the core of the hurricane.  Storms near the core were generating strong upper level divergence which was pumping mass away from the hurricane.  The circulation of Hurricane Hector was relatively small.  Winds to hurricane force extended out about 20 miles (30 km) from the center of circulation.  Winds to tropical storm force extended out about 60 miles (95 km) from the center.

Hurricane Hector will move through an environment favorable for intensification during the next several days.  Hector will move over water where the Sea Surface Temperature is between 27°C and 28°C.  An upper level ridge northeast of Hurricane Hector will produce easterly winds which will blow toward the top of the circulation.  However, the strongest easterly winds will be north of Hector and the vertical wind shear should not be too great over the hurricane.  Hurricane Hector is likely to continue to intensify and it could become a major hurricane.

Hurricane Hector will move south of the subtropical high pressure system over the Eastern North Pacific Ocean.  The subtropical high will steer Hector in a generally westerly direction during the next few days.  On its anticipated track Hurricane Hector will cross into the Central Pacific late in the weekend.  Hector could be southeast of Hawaii early next week.

Tropical Storm Hector Forms Southwest of Baja California

Tropical Storm Hector formed southwest of Baja California on Tuesday evening.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Hector was located at latitude 13.0°N and longitude 118.2°W which put it about 875 miles (1405 km) southwest of the southern tip of Baja California.  Hector 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 1006 mb.

A distinct low level center of circulation formed within an area of thunderstorms southwest of Baja California on Tuesday and the National Hurricane Center designated the system as Tropical Storm Hector.  The circulation of Tropical Storm Hector was still organizing.  Many of the stronger thunderstorms were occurring in two bands south and west of the center of circulation.  Additional bands of showers and storms were developing north and southeast of the center.  Thunderstorms near the center were beginning to generate upper level divergence which was pumping mass away from the tropical storm.

Tropical Storm Hector will move through an environment that is mostly favorable for intensification.  Hector will move over water where the Sea Surface Temperature is near 28°C.  An upper level ridge centered near Baja California was generating northeasterly winds which were blowing toward the top of the circulation.  Those winds were causing some vertical wind shear, but the shear will not be strong enough to prevent intensification.  Hector will intensify over the next several days and it will likely become a hurricane by Thursday night.

Tropical Storm Hector will move south of the subtropical high pressure system over the Eastern North Pacific Ocean.  The subtropical high will steer Hector in a general westerly direction.  On its anticipated track Tropical Storm Hector will move away from Mexico and toward the Central Pacific Ocean.

Minimal Tropical Storm Gilma Forms Well East of Hawaii

Minimal Tropical Storm Gilma formed well east of Hawaii on Friday.  A scatterometer on a polar orbiting satellite indicated that there were winds to tropical storm force near former Tropical Depression Eight-E and the National Hurricane Center named the system Tropical Storm Gilma.  At 11:00 a.m. EDT on Friday the center of Tropical Storm Gilma was located at latitude 14.9°N and longitude 128.4°W which put it about 1825 miles (2935 km) east of South Point, Hawaii.  Gilma was moving toward the west-northwest at 17 m.p.h. (28 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 of Tropical Storm Gilma was poorly organized.  There was a distinct low level center of circulation.  However, the stronger thunderstorms were occurring in bands east of the center.  Bands in the western half of the circulation consisted primarily of low clouds and showers.  A large upper level trough was located west of Tropical Storm Gilma.  The trough was producing strong northwesterly winds which were blowing across the top of the circulation.  Those winds were producing significant vertical wind shear and they were probably the reason why the stronger thunderstorms were occurring east of the center of circulation.

Tropical Storm Gilma will move through an environment unfavorable for intensification during the weekend.  Gilma will move over water where the Sea Surface Temperature is near 28°C.  However, the upper level trough will continue to produce significant vertical wind shear.  Gilma is likely to weaken to a depression and it could dissipate if the upper level winds blow the top of the circulation east of the low level center.

Tropical Storm Gilma will move south of a subtropical high pressure system over the Eastern North Pacific.  The strong wind shear will mean that Gilma will be steered by the winds lower in the atmosphere.  Those winds will push Gilma in a general westerly or west-northwesterly direction.

Fabio Strengthens to a Hurricane South of Baja California

Former Tropical Storm Fabio strengthened into a hurricane Monday morning as it moved south of Baja California.  At 11:00 a.m. EDT on Monday the center of Hurricane Fabio was located at latitude 12.8°N and longitude 110.9°W which put it about 700 miles (1125 km) south of the southern tip of Baja California.  Fabio was moving toward the west-northwest at 9 m.p.h. (15 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 989 mb.

The inner core of Hurricane Fabio exhibited signs of greater organization on Monday morning.  Microwave satellite imagery provided evidence of a rainband wrapping around the southern and eastern sides of the center of circulation.  There were intermittent signs that an eye could be forming at the center of circulation.  Several bands of showers and thunderstorms were revolving around the core of the circulation.  The strongest thunderstorms were occurring in bands south and east of the center of Hurricane Fabio.  The bands north and west of the center were weaker, which may indicate that there was some drier air in those parts of the circulation.  Thunderstorms near the core of Fabio were generating upper level divergence which was pumping mass away from the hurricane in all directions.

Hurricane Fabio will be moving through an environment that is very favorable for intensification.  Fabio will move over water where the Sea Surface Temperature is near 28.5°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  It will continue to strengthen and it could intensify rapidly once an eye forms and persists.  Fabio is forecast to strengthen to a major hurricane on Tuesday.

Hurricane Fabio is moving south of a subtropical ridge which is steering the hurricane toward the west-northwest.  The west-northwesterly motion is forecast to continue during the next several days.  On its anticipated track Hurricane Fabio will move away from Baja California.

Tropical Storm Fabio Develops West of Mexico

Tropical Storm Fabio developed west of Mexico on Sunday.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Fabio was located at latitude 12.0°N and longitude 107.4°W which put it about 770 miles (1240 km) south-southeast of the southern tip of Baja California.  Fabio was moving toward the west-northwest 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.

The circulation of Tropical Storm Fabio was still organizing.  There was a broad low level center of circulation, but it did not have a well developed inner core.  Multiple bands of showers and thunderstorms were revolving around the broad low level center.  The storms in the rainbands were generating some upper level divergence which was starting to pump mass away from the tropical storm.

Tropical Storm Fabio will move through an environment that is very favorable for intensification.  Fabio will move over water where the Sea Surface Temperature is near 28.5°C.  An upper level ridge northeast of Tropical Storm Fabio will produce easterly winds which will blow toward the top of the circulation.  However, the wind speed will be similar at all levels and there will not be much vertical wind shear.  Tropical Storm Fabio will continue to intensify in the favorable environment.  Once a primary rainband wraps around the center of circulation, an inner core will develop.  Tropical Storm Fabio could intensify rapidly when an eye starts to form.  Fabio could strengthen into a major hurricane in two or three days.

Tropical Storm Fabio was moving south of a subtropical ridge which was steering the tropical storm toward the west-northwest.  A general west-northwesterly motion is expected to continue during the next few days.  On its anticipated track the center of Tropical Storm Fabio will pass well to the south of Baja California.

Elsewhere over the Eastern North Pacific Ocean Tropical Depression Emilia continued to weaken over cooler water.  At 11:00 a.m. EDT on Sunday the center of Tropical Depression Emilia was located at latitude 19.3°N and longitude 123.0°W which put it about 880 miles (1415 km) west-southwest of the southern tip of Baja California.  Emilia was moving toward the west-northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1006 mb.

Tropical Storm Emilia Develops South of Baja California

Tropical Storm Emilia developed south of Baja California on Thursday morning.  At 11:00 a.m. EDT on Thursday the center of Tropical Storm Emilia was located at latitude 14.4°N and longitude 112.4°W which put it about 610 miles (980 km) south-southwest of the southern tip of Baja California.  Emilia 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 1005 mb.

The distribution of thunderstorms around Tropical Storm Emilia was asymmetrical.  Most of the showers and thunderstorms were occurring in bands west and north of the center of circulation.  The center was located near the eastern edge of a cluster of thunderstorms.  Bands east of the center consisted of showers and low clouds.  The cluster of storms west of the center of circulation was generating upper level divergence which was pumping mass away to the west and north of the tropical storm.

Tropical Storm Emilia will move through an environment somewhat favorable for intensification during the next day or two.  Emilia will move over water where the Sea Surface Temperature is near 28°C.  An upper level ridge centered near the southern tip of Baja California was producing northeasterly winds which were blowing toward the top of the circulation.  Those winds were causing moderate vertical wind shear and they were probably the reason why most of the thunderstorms were located west and north of the center of circulation.  The vertical shear is likely to limit intensification during the next 24 hours.  The shear is forecast to decrease on Friday and Tropical Storm Emilia could strengthen faster if that occurs.

The portion of the ridge in the middle troposphere was steering Tropical Storm Emilia toward the west-northwest and that general motion is expected to continue for several more days.  On its anticipated track Emilia will move farther away from the west coast of Mexico.

Tropical Storm Daniel Develops Southwest of Baja California

Tropical Storm Daniel developed southwest of Baja California on Sunday after a relatively quiet week in the tropics.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Daniel was located at latitude 16.0°N and longitude 115.9°W which put it about 615 miles (990 km) southwest of the southern tip of Baja California.  Daniel was moving toward the north 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 1006 mb.

Microwave satellite data indicated that a better organized center of circulation was present inside former Tropical Depression Five-E and the National Hurricane Center designated the system as Tropical Storm Daniel on Sunday morning.  A band of showers and thunderstorms wrapped around the south and east sides of a small tight center of circulation.  Several bands of showers and thunderstorms were revolving around the center.  Bands northwest of the center of circulation consisted primarily of showers and lower clouds.  Storms near the center began to generate upper level divergence which pumped mass away from the tropical storm.

Tropical Storm Daniel will move through an environment favorable for intensification for about another 24 hours.  Daniel is moving over water where the Sea Surface Temperature is near 27°C.  Tropical Storm Daniel will move over cooler water in about a day or so.  There is an upper level low northwest of Daniel.  The low is generating southerly winds which are blowing toward the top of the tropical storm.  Those winds are causing moderate vertical wind shear, but the shear will not be strong enough to prevent intensification.  Tropical Storm Daniel could intensify a little more during the next 24 hours, but Daniel is likely to weaken when it moves over cooler water.

The upper low northwest of Tropical Storm Daniel was steering the tropical storm toward the north.  The upper low is moving toward the west.  Tropical Storm Daniel if forecast to turn more toward the northwest on Monday as it moves around the western side of the upper low.  When Daniel moves over cooler water the clouds will not grow as tall and the tropical storm will be steered by the winds lower in the atmosphere.  The subtropical high over the Pacific Ocean is forecast to steer Daniel more toward the west later next week after the tropical storm weakens.

Stronger Tropical Storm Carlotta Nears Acapulco

A stronger Tropical Storm Carlotta moved near Acapulco, Mexico on Saturday night.  At 11:00 p.m. EDT the center of Tropical Storm Carlotta was located at latitude 16.6°N and longitude 99.9°W which put it 20 miles (35 km) south of Acapulco.  Carlotta was moving toward the northwest 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 997 mb.  A Tropical Storm Warning was in effect for the portion of the coast from Punta Maldonado to Tecpan de Galeana.

The center of Tropical Storm Carlotta remained over water on Saturday and the circulation strengthened.  A small eye formed 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 the circulation.  Storms in the core were generating upper level divergence which pumped mass away from the tropical storm.

The future intensity of Tropical Storm Carlotta will depend on whether or not the center remains over water.  The Sea Surface Temperature of the water south of Mexico is near 30°C.  Carlotta will move through an area where the upper level winds are weak.  If the center of Carlotta remains over water, then it could intensify more on Sunday.  However, if the center moves inland, then Tropical Storm Carlotta will weaken quickly when the circulation is disrupted by the Sierra Madre del Sur mountains.

Tropical Storm Carlotta moved near the western end of a ridge over Mexico.  The ridge steered Carlotta slowly toward the northwest on Saturday and that general motion is forecast to continue on Sunday.  On its forecast track the center of Tropical Storm Carlotta will move almost parallel to the coast of Mexico west of Acapulco.  A small deviation to the left of the anticipated track will keep the center over water.  A small deviation to the right of the anticipated track will bring Tropical Storm Carlotta inland.  Carlotta will cause gusty winds near the coast.  Heavy rain will fall north of the center and over the south slopes of the Sierra Madre del Sur Mountains.  Flash floods are likely because of the slow movement of Tropical Storm Carlotta.

TD 4E Strengthens to Tropical Storm Carlotta

Tropical Depression Four-E strengthened to Tropical Storm Carlotta south of Mexico on Friday afternoon.  At 2:00 p.m. EDT on Friday the center of Tropical Storm Carlotta was located at latitude 16.0°N and longitude 99.4°W which put it about 60 miles (95 km) south-southeast of Acapulco, Mexico.  Carlotta was moving toward the 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.  A Tropical Storm Warning was in effect for the portion of the coast from Tecpan de Galeana to Lagunas de Chacahua, Mexico.

A single, distinct center of circulation developed in Tropical Depression Four-E on Friday afternoon and the National Hurricane Center designated the system as Tropical Storm Carlotta.  It is possible that the mountains in Mexico deflected the circulation in the lower levels and contributed to the improved organization of Tropical Storm Carlotta.  Stronger thunderstorms were forming near the center of circulation.  A primary band of showers and thunderstorms developed east and south of the core of Carlotta.  Other rainbands were revolving around the core of the tropical storm.  Storms in the core were generating upper level divergence and Carlotta looked like a tropical storm on satellite images.

Tropical Storm Carlotta will remain in an environment favorable for intensification while the center is over water.  The Sea Surface Temperature of the water south of Mexico is near 30°C.  The upper level winds are weak in that area and there is little vertical wind shear.  Carlotta could strengthen further during the next 12 hours.  When the center nears the coast of Mexico, the circulation could begin to pull in drier air from over the land.  If that happens, then Tropical Storm Carlotta could start to weaken even before the center officially makes landfall.

The steering winds are weak around Tropical Storm Carlotta.  A trough in the lower levels is moving across the southwestern Gulf of Mexico and it appears to be pulling Carlotta slowly toward the northeast.  On its anticipated track the center of Tropical Storm Carlotta will reach the coast of Mexico in 12 to 18 hours.  Tropical Storm Carlotta is expected to make landfall east of Acapulco.  Carlotta will produce some gusty winds but the greater risks are heavy rain and flash floods.

Elsewhere, Tropical Depression Bud is moving over the Gulf of California.  At 11:00 a.m. EDT on Friday the center of Tropical Depression Bud was located at latitude 25.3°N and longitude 110.0°W which put it about 70 miles (110 km) west of Los Mochis, Mexico.  Bud was moving toward the north at 12 m.p.h. (19 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 1002 mb.  Bud could drop heavy rain and cause flash floods in the states of Sinaloa, Sonora and Chihuahua.