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Eastern North Pacific Tropical Weather Discussion



295 
AXPZ20 KNHC 242205
TWDEP 

Tropical Weather Discussion 
NWS National Hurricane Center Miami FL
2205 UTC Mon Sep 24 2018 

Tropical Weather Discussion for the eastern Pacific Ocean from 
the Equator to 32N, east of 140W. The following information is 
based on satellite imagery, weather observations, radar, and 
meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through 
2115 UTC.

...SPECIAL FEATURE... 

A broad area of low pressure is analyzed as 1008 mb surface low 
near 14N105W. Numerous moderate isolated strong convection is 
observed within 120 nm NW semicircle of the low. Scattered 
moderate convection in bands are elsewhere from 09N to 18N 
between 99W and 110W. Fresh southwesterly monsoonal flow is well 
south of the low, across the tropical waters from 06N to 10N 
between 101W and 117W. Environmental conditions are expected to 
be conducive for development, and a tropical depression is 
likely to form within the next day or so while the system moves 
west-northwestward well off the coast of Mexico. There is still 
much uncertainty at this time, however for now expect fresh to 
strong winds, and building seas, to spread north across the 
offshore waters from 15N to 23N on Wed through Sat, with mixed 
swell, in the form of 8 to 16 ft seas. Higher winds are highly 
possible across the waters west of the Baja Peninsula over the 
remainder weekend. Refer to the East pacific tropical Weather 
Outlook under WMO/AWIPS headers ABPZ20 KMIA/MIATWOEP for 
additional information.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough extends from 10N85W to 10N100W to a low 
pressure...possible tropical cyclone...near 14N105W to 11N110W 
to 11N125W to 10N136W. Numerous moderate isolated strong 
convection is in the Gulf of Panama and from 06N to 09N between 
85W and 91W. Scattered moderate convection is elsewhere from 07N 
to 14N between 113W and 130W, and from 07N to 18N W of 130W. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 

See the Special Features paragraph above. Surface ridging to the 
west will continue to retract away of the region during the next 
few days as a surface low, with a high chance of becoming a 
tropical cyclone, tracks west-northwest. Gentle to moderate 
northwest flow is forecast west of the Baja California through 
Thu morning, then light to gentle winds are expected through 
Fri. 

Gulf of California: Gentle to locally moderate variable winds 
forecast across the gulf waters north of 30N through much of the 
period. Otherwise, light to gentle variable winds expected 
across the remainder gulf waters through the weekend.

Gulf of Tehuantepec: Fresh to locally strong nocturnal drainage 
is forecast tonight with a strong event expected Sat morning. A 
low pressure is forecast to develop over Guatemala offshore 
waters on Thu along with fresh to strong winds. The low will 
move west to south of Tehuantepec on Friday where it is expected 
to slightly intensify. Seas are forecast to build to 14 ft over 
the weekend.

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR...

Gulf of Papagayo: Moderate to locally fresh east nocturnal 
drainage flow expected through Thu night with seas building to 
8 ft. 

Light and variable winds are forecast elsewhere north of the 
monsoon trough which is meandering between 09N and 12N. Moderate 
southwest flow is forecast south of the monsoon trough.

REMAINDER OF THE AREA...   

See the Special Features paragraph above. A broad ridge 
continues across the subtropics accompanied by moderate to 
locally fresh anticyclonic flow south of 23N west of 120W.

$$
Ramos