Tag Archives: 90E

Possible Development East-Northeast of Hawaii

The National Hurricane Center (NHC) indicated that a low pressure system over the Eastern North Pacific Ocean east-northeast of Hawaii could develop into a subtropical or a tropical cyclone during the next 48 hours. The low pressure system is currently designated as Invest 90E. At 1:00 p.m. EST on Thursday the center of Invest 90E was located at latitude 21.8°N and longitude 136.1°W which put it about 1280 miles (2065 km) east-northeast of Hilo, Hawaii. It 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 1006 mb.

The National Hurricane Center issued a Special Tropical Weather Outlook on Thursday afternoon which indicated that a low pressure system over the Eastern North Pacific Ocean had a 40% probability of development into a subtropical or a tropical cyclone during the next 48 hours. The low pressure system has been moving slowly toward the west between Baja California and Hawaii. The low pressure system currently has a hybrid structure. A well organized low level center of circulation was evident on visible satellite images. The low level center was located just to the east of a low pressure system in the middle and upper troposphere. The upper low was producing southerly winds that were blowing toward the top of the low level circulation. Those winds were causing moderate vertical wind shear and the wind shear was affecting the structure of the system. The strongest thunderstorms were occurring in bands north and east of the low level center of circulation. Bands south and west of the low level center consisted primarily of showers and lower clouds.

Invest 90E will move through an environment somewhat favorable for the formation of a subtropical or a tropical cyclone during the next 24 hours. The surface center of circulation will move over water where the Sea Surface Temperatures are near 24˚C. Since the upper low contains colder air, that water temperature is warm enough to support the development of a subtropical or a tropical cyclone. The low in the middle and upper troposphere will continue to cause moderate vertical wind shear. The wind shear will inhibit the development of a tropical cyclone. The current hybrid structure of Invest 90E and the marginally warm Sea Surface Temperatures would favor the development of a subtropical cyclone. However, if the strength of the upper level winds decreases, then a tropical cyclone could form.

Invest 90E will move south of a surface high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer the low level center of circulation toward the west-northwest during the next 24 hours. On its anticipated track Invest 90E will move slowly toward the Central Pacific Ocean.

Tropical Development Possible Southwest of Mexico

Development of a tropical cyclone southwest of Mexico is possible during the next few days. At 2:00 p.m. EDT on Friday the center of Invest 90E was located at latitude 11.2°N and longitude 102.5°W which put it about 415 miles (670 km) south-southwest of Acapulco, Mexico. The Invest was moving toward the west at 7 m.p.h. (11 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 low pressure, currently designated as Invest 90E, exhibited more organization on Friday afternoon. The National Hurricane Center (NHC) issued a Special Tropical Weather Outlook for the low pressure system. NHC indicated that there was a 40% probability that the system would develop into a tropical depression or a tropical storm during the next 48 hours and a 60% chance that development would occur during the next five days.

More thunderstorms developed near the center of Invest 90E. Bands of showers and thunderstorms also developed and the bands began to revolve around the center of the low pressure system. Storms near the center began to generate upper level divergence that pumped mass away from the system.

Invest 90E will move through an environment favorable for develop of a tropical cyclone during the next 36 hours. It will move over water where the Sea Surface Temperatures will be near 29°C. The low pressure system will move under the center of an upper level ridge southwest of Mexico. The winds are weak near the center of the ridge and there will be little vertical wind shear. Invest 90E is likely to develop into a tropical depression and it could quickly intensify into a tropical storm.

Invest 90E will move southeast of a large high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer the Invest slowly toward the west-northwest. On its anticipated track the low pressure system will remain southwest of Mexico during 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.

Unusual Development Possible Southwest of Baja California

Unusual development of a tropical or subtropical cyclone is possible southwest of Baja California during the next few days.  The National Hurricane Center (NHC) issued a special Tropical Weather Outlook on Thursday afternoon for a weather system southwest of Baja California.  NHC indicated that there is a 50% probability of development of a tropical or subtropical cyclone during the next five days.  No tropical cyclone or subtropical cyclone is known to have developed over the Eastern North Pacific Ocean in January.  The record extends back to 1949, but it is most complete for the era of Geostationary Operational Environmental Satellites (GOES) which extends from 1970 to the present.

A broad area of low pressure was located about 1300 miles (2100 km) southwest of the southern tip of Baja California.  Clusters of showers and thunderstorms were occurring in parts of the low pressure system.  Visible satellite images were not showing evidence that the showers and thunderstorms were forming into rainbands.  There was a broad area of low pressure, but there was no evidence of a distinct low level center of circulation.

The broad area of low pressure will move through an environment somewhat favorable for the formation of a tropical or subtropical cyclone during the next few days.  It will move over water where the Sea Surface Temperature is near 27°C, which means that there will be enough energy in the ocean to support a tropical cyclone.  An upper level low is northwest of the broad surface low pressure system.  The upper level low is producing strong southwesterly winds which are blowing across the top of the broad low pressure system.  Those winds will cause moderate vertical wind shear, which will inhibit the formation of a tropical cyclone.  If the winds weaken, a tropical cyclone could form, but if the wind shear remains stronger, a subtropical cyclone could develop.  As mentioned above, the National Hurricane Center indicates that there is a 50% probability of development of a tropical or subtropical cyclone.

The broad area of low pressure is forecast to move slowly toward the north during the next several days.  If a tropical or subtropical cyclone develops with taller thunderstorms, then the southwesterly winds blowing around the upper low will steer the cyclone toward Baja California.  The system could bring gusty winds and heavy rain to Baja California and northern Mexico in a few days.

Possible Tropical Development South of El Salvador

A broad area of low pressure has formed over the Eastern North Pacific Ocean south of El Salvador.  The environment is favorable for the development of a tropical cyclone.  The National Hurricane Center (NHC) has designated the low pressure system as Invest 90E.  NHC is indicating that there is a 50% probability of the formation of a tropical depression during the next 48 hours and an 80% probability of formation during the next five days.

At 2:00 p.m. EDT on Monday the center of Invest 90E was located at latitude 7.9°N and longitude 89.5°W which put it about 370 miles (595 km) south of San Salvador, El Salvador.  Invest 90E was stationary.  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.

More thunderstorms formed on Monday around a broad area of low pressure south of El Salvador.  Visible satellite imagery suggested a broad counterclockwise rotation of the area of thunderstorms, but there were no indications of a well developed core of the circulation.  Several smaller centers of rotation were visible within the broad low pressure system, but these may be transient features.  The broad area of thunderstorms was producing upper level divergence.  The divergence is pumping out mass and if that continues, then the surface pressure will decrease.

The area of low pressure is in an environment favorable for tropical development.  It is moving over water where the Sea Surface Temperature is near 30°C.  The low is sitting underneath an upper level ridge and the winds in the upper level are weak.  There is little vertical wind shear and there is nothing to inhibit upper level divergence.  The circulation should continue to organize, which is why the probability of formation of a tropical cyclone is high.

The area of low pressure is in an area where the steering currents are weak and Invest 90E was nearly stationary on Monday.  A high pressure system northeast of the broad area of low pressure system is expected to strengthen.  When that happens, the high is likely to steer the area of low pressure toward the northwest.