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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 171608
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Wed Oct 17 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 1200 UTC surface analysis and satellite imagery through 
1515 UTC.

...SPECIAL FEATURE...

Satellite-derived winds and surface observations indicate that 
an elongated low pressure system has developed about 100 miles 
south of Guatemala. Although associated shower and thunderstorm 
activity is currently disorganized, environmental conditions are 
expected to be conducive for additional development, and a 
tropical depression or a tropical storm is likely to form during 
the next day or two. The system is forecast to moves generally 
toward the west-northwest near or just offshore the coast of 
southern Mexico.

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

The monsoon trough extends 09N83W to low pres near 12N90W to 
11N114W to 08N120W to 10N139W. Scattered moderate convection is 
within 120 nm south of the monsoon trough E of 89W. Scattered 
moderate isolated strong convection is N of 09N between 91W and 
99W, and from 06N to 13N W of 127W. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 

The remnants of Tropical Depression Tara are located near 20N 
106W. Scattered moderate convection is within 75 nm NW quadrant 
of the center. Strong upper level winds and interaction with the 
mountainous terrain of Mexico will cause the low to weaken. It 
is expected to dissipate during the next 24 hours. Heavy 
rainfall will continue to impact coastal areas today.

High pressure ridge north of the area extending SSE to near the 
Revillagigedo Islands is maintaining moderate to locally fresh 
NW winds over the offshore forecast waters W of Baja California. 
The ridge will maintain its influence over the offshore waters W 
of Baja California throughout the week, yielding seas of 4-7 ft.

Fresh to strong NW winds will continue across the Gulf of 
California through Friday.

A gap wind event is in the Gulf of Tehuantepec as high pressure 
builds behind a stationary front in the W Gulf of Mexico. Winds 
in Tehuantepec are up to 30 kt with seas building to 13 ft 
within the next two days. The gap wind event will merge with the 
conditions generated by the possible tropical cycone on Friday.

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

Moderate to fresh SW monsoonal flow will continue across the 
region through Wed, with active showers and thunderstorms 
expected to continue across much of Central America and the 
adjacent Pacific coastal waters, spreading well inland. Long 
period cross-equatorial SW swell will maintain 5 to 8 ft seas 
across the forecast area during the next few days. As mentioned 
above, global weather models suggest the chance for low pressure 
to develop offshore of the coast between Papgayo and south of 
Gulf of Tehuantepec in the next few days, which will help to 
focus very heavy rainfall across the region. 

REMAINDER OF THE AREA...

A stationary front extending from 30N136W to 24N140W will weaken 
today. Long period NW swell behind the front and cause seas to 
build to between 8 and 9 ft generally N of 15N and W of 132W.

Satellite-derived wind and altimeter data indicate moderate to 
fresh monsoonal flow N of 07N and south of the monsoon trough. 
An area of 7 to 9 ft seas in long period SW swell is noted 
between 95W and 108W, and is expected to continue across this 
general area through early Thu.

$$
NR