Category Archives: Eastern and Central Pacific

TCs between Mexico and Hawaii

Tropical Depression Four-E Forms Southwest of Baja California

Tropical Depression Four-E formed just southwest of Baja California on Monday night.  At 11:00 p.m. EDT on Monday the center of Tropical Depression Four-E was located at latitude 20.5°N and longitude 112.6°W which put it about 240 miles (385 km) southwest of the southern tip of Baja California.  The depression 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 were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1004 mb.

The circulation around a low pressure system southwest of Baja California exhibited more organization on Monday night and the National Hurricane Center designated the system as Tropical Depression Four-E.  The distribution of thunderstorms around the depression was asymmetrical.  A band of stronger thunderstorms wrapped around the northern side of the center of circulation.  The strongest winds were occurring in that band of storms.  Bands in other parts of the depression consisted of primarily of showers and lower clouds.

Tropical Depression Four-E will move into an environment mostly unfavorable for intensification.  The depression will move over water where the Sea Surface Temperature is near 24.5°C.  An upper level trough over the western U.S. and an upper level ridge over Mexico will produce southwesterly winds which will blow toward the top of the depression.  Those winds will cause moderate vertical wind shear.  The colder water and moderate shear will prevent the potential for significant intensification.  The depression could maintain its intensity during the next six to twelve hours but it is likely to weaken later on Tuesday.

Tropical Depression Four-E will move around the western end of a ridge of high pressure over Mexico.  The ridge will steer the depression slowly toward the northwest.   On its anticipated track Tropical Depression Four-E will pass west of Baja California.

Tropical Storm Boris Develops East-Southeast of Hawaii

Tropical Storm Boris developed east-southeast of Hawaii on Thursday afternoon.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Boris was located at latitude 11.2°N and longitude 137.1°W which put it about 1330 miles (2145 km) east-southeast of Hilo, Hawaii.  Boris was moving toward the west-northwest at 9 m.p.h. (15 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.

More thunderstorms developed Thursday afternoon near a low pressure system southeast of Hawaii that was previously designated as Tropical Depression Three-E.  A scatterometer on board a satellite detected winds to 40 m.p.h. (65 km) near the center of the low pressure system and the National Hurricane Center designated the system as Tropical Storm Boris.  A band of showers and thunderstorms wrapped around the southern and eastern sides of the center of circulation and the strongest winds were occurring in that band of storms.  A few other short bands of showers and thunderstorms developed in the eastern half of Boris.  Bands in the western half of the circulation consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out about 50 miles from the center of circulation.

Tropical Storm Boris will move through an environment marginally favorable for intensification during the next 12 to 24 hours.  Boris will move over water where the Sea Surface Temperature is near 26.5°C.  A large upper level trough between Hawaii and the West Coast of the U.S. will produce southwesterly winds which will blow toward the top of the circulation.  Those winds will cause moderate vertical wind shear and the shear will limit intensification.  In addition, there is drier air north and west of Tropical Storm Boris.  Boris could intensify during the next 12 hours in spite of the moderate vertical wind shear and drier air.  However, Tropical Storm Boris will move into a region where the upper level winds are stronger during the weekend.  When the vertical wind shear increases, Boris will weaken.

Tropical Storm Boris will move south of a subtropical high pressure system over the Eastern North Pacific Ocean.  The will steer Boris toward the west-northwest during the next 24 hours.  When Tropical Storm Boris weakens during the weekend, it will be steered by winds closer to the surface.  Those winds will steer Boris toward the west.  On its anticipated track the weakening Tropical Storm Boris will pass southeast of Hawaii.

Tropical Storm Amanda Drops Heavy Rain on Guatemala and El Salvador

Tropical Storm Amanda dropped heavy rain on parts of Guatemala and El Salvador on Sunday.  At 8:00 a.m. EDT on Sunday the center of Tropical Storm Amanda was located at latitude 14.2°N and longitude 90.4°W which put it about 30 miles (50 km) south-southeast of Guatemala City, Guatemala.  Amanda was moving toward the north-northeast at 9 m.p.h. (15 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.

Tropical Storm Warnings remained in effect for the entire coasts of Guatemala and El Salvador.

The circulation around former Tropical Depression Two-E strengthened on Sunday morning as it approached the coast of Guatemala and the National Hurricane Center designated the system as Tropical Storm Amanda.  Winds to tropical storm force extended out 50 miles (80 km) on the eastern side of Amanda.  Winds on the western side of the circulation were mostly less than tropical storm force.

The heaviest rain in Tropical Storm Amanda was falling near the center of circulation and in bands on the eastern side of the circulation.  Tropical Storm Amanda was located on the eastern side of a much larger counterclockwise circulation that is sometimes called a Central American Gyre (CAG).  The CAG will steer Amanda toward the north during the next 24 to 36 hours.  On its anticipated track Tropical Storm Amanda will move across Guatemala toward the southern Yucatan peninsula.  Amanda will drop locally heavy rain over parts of El Salvador, Guatemala, Belize and eastern Mexico.  The heavy rain could cause flash floods in some locations.

The lower level part of the circulation of Tropical Storm Amanda will weaken while the tropical storm moves over land.  The circulation of Amanda that is above the surface could move over the Bay of Campeche early next week.  A new tropical cyclone could form over the Bay of Campeche if that happens.  The National Hurricane Center is indicating that there is a 50% probability of the formation of a tropical cyclone over the Bay of Campeche during the next five days.

Tropical Depression Two-E Forms Near Guatemala

Tropical Depression Two-E formed near the coast of Guatemala on Saturday.  At 8:00 p.m. EDT on Saturday the center of Tropical Depression Two-E was located at latitude 12.6°N and longitude 91.0°W which put it about 90 miles (145 km) south of Puerto San Jose, Guatemala.  The depression was moving toward the north-northeast at 4 m.p.h. (6 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 1005 mb.

Tropical Storm Warnings were in effect for the entire coasts of El Salvador and Guatemala.

A distinct center of circulation developed south of the coast of Guatemala on Saturday.  More thunderstorms formed near the center and the National Hurricane Center designated the system as Tropical Depression Two-E.  Thunderstorms continued to form near the center.  Bands of showers and thunderstorms were revolving around the center of the depression.  The depression was near the center of a much larger counterclockwise circulation that is sometimes called a Central American Gyre (CAG).

Tropical Depression Two-E will move through an environment favorable for intensification during the next few hours.  The depression will move over water where the Sea Surface Temperature is near 30°C.  It will move under an upper level ridge over Central America.  The upper level winds are weak and there will be little vertical wind shear.  Tropical Depression Two-E could strengthen during the next few hours and there is a chance it could intensify into a tropical storm.

Tropical Depression Two-E will move around the western end of a high pressure system.  The high will steer the depression toward the north-northeast.  On its anticipated track the center of Tropical Depression Two-E will make landfall on the coast of Guatemala on Sunday.  The depression could drop heavy rain over  Guatemala, El Salvador and western Honduras.  The heavy rain could cause flash floods.

One-E Becomes Earliest East Pacific Tropical Depression

Tropical Depression One-E became Saturday the earliest tropical depression for form over the Eastern North Pacific Ocean during the satellite era which began in 1966.  The previous date of the earliest formation over that region was May 9, 2017 when a depression formed that would ultimately strengthen into Tropical Storm Adrian.  At 11:00 a.m. EDT on Saturday the center of Tropical Depression One-E was located at latitude 14.1°N and longitude 116.1°E which put it about 730 miles (1175 km) southwest of the southern tip of Baja California.  The depression 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 were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1006 mb.

More thunderstorms developed near the center of a low pressure system previously designated as Invest 90E southwest of Baja California on Saturday morning and National Hurricane Center designated the system as Tropical Depression One-E.  Tropical Depression One-E is the first tropical depression to form over the Eastern North Pacific Ocean during the month of April in the satellite era .  The distribution of thunderstorms around the depression was asymmetrical.  Many of the stronger thunderstorms were occurring in bands in the southern half of the circulation.  Bands in the northern half of the circulation consisted primarily of showers and lower clouds.  The southern half of the circulation was over warmer Sea Surface Temperatures, which may have contributed to the development of thunderstorms in that part of the tropical depression.

Tropical Depression One-E will move through an environment somewhat favorable for intensification during the next 24 hours.  The depression will move over water where the Sea Surface Temperature is near 26.5°C.  It will move under the western end of an upper level ridge over the Eastern North Pacific Ocean.  The ridge will produce southerly winds which will blow toward the top of the circulation.  Those winds will cause moderate vertical wind shear and they will inhibit intensification.  Conditions could be favorable enough to allow Tropical Depression One-E to strengthen into a tropical storm during the next 24 hours.  The depression will move over cooler Sea Surface Temperatures later on Sunday, which will cause it to weaken.

Tropical Depression One-E will move around the western end of a high pressure system over the Eastern North Pacific Ocean during the next 24 hours.  The high will steer the depression toward the northwest on Saturday.  A second high pressure system over the North Pacific Ocean will block the northward movement of the depression later on Sunday.  The second high will steer the depression more toward the west later in the weekend.

Possible Tropical Development

A tropical cyclone could possibly form south of Baja California during the next few days.  The system has been designated as Invest 90E.  At 2:00 p.m. EDT on Thursday the center of Invest 90E was located at latitude 10.2°N and longitude 111.7°W which put it about 870 miles (1405 km) south of the southern tip of Baja California.  It was moving toward the west at 9 mp.h. (15 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 1008 mb.

An area of thunderstorms has persisted south of Baja California for the past several days.  More thunderstorms developed on Thursday.  Visible satellite images indicated that the thunderstorms were organizing into bands and there was some counterclockwise rotation of the bands around a center of circulation.  There appeared to be a low level center of circulation.  However, there were not enough thunderstorms around the center of circulation for the system to be classified as a tropical cyclone.

Invest 90E will move through an environment somewhat favorable for the formation of a tropical cyclone during the next 48 hours.  it will move over water where the Sea Surface Temperature is near 29°C.  Invest 90E will move under the western end of an upper level ridge over the Eastern North Pacific Ocean.  The ridge will produce southerly winds which will blow across the top of the system.  Those winds will cause moderate vertical wind shear and they will inhibit the formation of a tropical cyclone.   If the strength of the upper level wind diminishes slightly, then the environment will become more favorable for the formation of a tropical cyclone.  The National Hurricane Center indicated that the probability of formation of a tropical cyclone during the next two days was 40%.

Invest 90E will move around the western end of a high pressure system over the far Eastern North Pacific Ocean during the next several days.  The high will steer the system toward the northwest.  On its anticipated track Invest 90E will remain well to the southwest of Baja California during the weekend.

TD 20-E Strengthens into Tropical Storm Raymond

Tropical Depression Twenty-E strengthened into Tropical Storm Raymond on Friday morning.  At 10:00 a.m. EST on Friday the center of Tropical Storm Raymond was located at latitude 14.1°N and longitude 108.8°W which put it about 610 miles (985 km) south of the southern tip of Baja California.  Raymond was moving toward the north-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 1005 mb.

The circulation around Tropical Storm Raymond exhibited greater organization on Friday morning.  More thunderstorms developed close to the center of circulation.  Storms near the center of circulation were generating upper level divergence which was pumping mass away from the tropical storm.  The distribution of thunderstorms was asymmetrical.  More of the stronger thunderstorms were forming in bands in the eastern half of the circulation.  There were fewer thunderstorms in the bands around the western side of Raymond.  Winds to tropical storm force extended out 60 miles (95 km) in the eastern half of the tropical storm.  Wind speeds on the western side of the circulation were mostly less than tropical storm force.

Tropical Storm Raymond will move through an environment favorable for intensification during the next 24 hours.  Raymond will move over water where the Sea Surface Temperature is 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 Raymond is likely to intensify during the next 24 hours and it could strengthen into a hurricane.

Tropical Storm Raymond will move around the western side of a ridge of high pressure over Mexico.  The ridge will steer Raymond toward the north during the next several days.  On its anticipated track Tropical Storm Raymond will move slowly toward the southern tip of Baja California.

Tropical Depression Twenty-E Forms South of Baja California

Tropical Depression Twenty-E formed south of Baja California on Thursday night.  At 10:00 p.m. EST on Friday the center of Tropical Depression Twenty-E was located at latitude 13.0°N and longitude 108.4°W which put it about 690 miles (1110 km) south of the southern tip of Baja California.  The depression was moving toward the north-northwest at 5 m.p.h.(8 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 1007 mb.

More thunderstorms developed near the center of a low pressure system over the Eastern North Pacific Ocean south of Baja California on Thursday night and the National Hurricane Center designated the system as Tropical Depression Twenty-E.  The circulation around the depression was still organizing.  Thunderstorms were forming near the center of the depression.   The thunderstorms near the center were generating upper level divergence which was pumping mass away from the depression.  Other thunderstorms were developing in bands around the circulation.

Tropical Depression Twenty-E will move through an environment favorable for intensification during the next day or two.  The depression will move over water where the Sea Surface Temperature is near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  The depression is likely to strengthen into a tropical storm on Friday.

Tropical Depression Twenty-E will move around the western end of a ridge of high pressure over Mexico.  The ridge will steer the depression toward the north.  On its anticipated track the depression will move slowly toward the southern tip of Baja California.

Tropical Storm Priscilla Develops Near West Coast of Mexico

Tropical Storm Priscilla developed near the west coast of Mexico on Sunday.  At 2:00 p.m. EDT on Sunday the center of Tropical Storm Priscilla was located at latitude 18.6°N and longitude 104.0°W which put it about 55 miles (90 km) southeast of Manzanillo, Mexico.  Priscilla 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  1004 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Punta San Telmo to Playa Perula, Mexico.

A distinct low level center of circulation formed within a cluster of thunderstorms near the west coast of Mexico on Sunday and the National Hurricane Center designated the system as Tropical Storm Priscilla.  Thunderstorms were forming near the center of circulation.  Bands of showers and thunderstorms were also developing and the bands were revolving around the center of Priscilla.  Storms near the center were generating upper level divergence which was pumping mass away to the north of the tropical storm.  The circulation around Priscilla was small.  Winds to tropical storm force extended out 35 miles (55 km) from the center of circulation.

Tropical Storm Priscilla will move through an environment favorable for intensification during the next few hours.  The center of Priscilla will be over water where the Sea Surface Temperature is near 29°C.  It will be in a region where the upper level winds are not too strong and there will not be a lot of vertical wind shear.  However, the center of Tropical Storm Priscilla will be very close to Mexico.  The circulation around Priscilla will begin to pull drier air from over the land into the tropical storm.  Tropical Storm Priscilla could strengthen during the next few hours, but it is likely to weaken quickly when the center moves over Mexico.

Tropical Storm Priscilla will move around the western end of a high pressure system over Mexico.  The high will steer Priscilla on a track that will be a little to the west of straight north.  On its anticipated track, the center of Tropical Storm Priscilla will make landfall on the west coast of Mexico between Tecoman and Manzanillo within a few hours.  Priscilla could drop locally heavy rain which could cause flash floods in some places.

Tropical Storm Octave Forms over Eastern North Pacific

Tropical Storm Octave formed over the Eastern North Pacific Ocean on Thursday evening.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Octave was located at latitude 9.8°N and longitude 127.2°W which put it about 1455 miles (2345 km) southwest of the southern tip of Baja California.  Octave was moving toward the west at 3 m.p.h. (5 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.

More thunderstorms formed near the center of a small low pressure system between Mexico and Hawaii and the National Hurricane Center designated the system as Tropical Storm Octave.  The circulation around Octave exhibited more organization and tropical characteristics on Thursday evening.  There was a distinct low level center of circulation with thunderstorms.  Several bands of showers and thunderstorms were revolving around the center.  Storms near the center generated upper level divergence which pumped mass away from the tropical storm.  The circulation around Tropical Storm Octave was small.  Winds to tropical storm force only extended out 35 miles (55 km) from the center of circulation.

Tropical Storm Octave will move through an environment mostly favorable for intensification.  Octave will move over water where the Sea Surface Temperature is 28°C.  It will be in a region where the upper level winds are weak and there will be little vertical wind shear.  However, there appears to be drier air north of Tropical Storm Octave.  If the circulation pulls drier air into the core of Octave, then thunderstorms around the center would weaken which would make intensification unlikely.  Tropical Storm Octave could strengthen a little during the next 24 hours.

Tropical Storm Octave will be in a region where the winds at the steering level are weak.  Octave is forecast to move little during the next few days.  Because Tropical Storm Octave will not move much, it will remain well away from any land area.