Tropical Weather Discussion

axpz20 knhc 231600

Tropical weather discussion 
NWS National Hurricane Center Miami FL
1605 UTC sun Sep 23 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 
1500 UTC.

...Intertropical convergence zone/monsoon trough... 

The monsoon trough extends from 09n84w to 09n100w to 10n120w to 
09n140w. Numerous moderate isolated strong convection is N of 
03n E of 81w. Scattered moderate convection is within 120 nm 
either side of the monsoon between 84w and 108w, from 05n to 10n 
between 110w and 127w, and from 08n to 15n between 120w and 


Offshore waters within 250 nm of Mexico... 

A surface trough is from 16n99w to 11n99w accompanied with 
numerous moderate isolated strong convection from 11n to 16n 
between 97w and 105w. This area of low pressure is forecast to 
spawn a center of low pressure near 13n105w this evening. The 
low is expected to track northwest accompanied by tstms just 
beyond 250 nm seaward. Gentle to locally moderate cyclonic winds 
will shift northwest through the offshore waters mostly seaward 
of 200 nm, with the low reaching a position near 17n116 Fri 
morning. By Thu night southerly swells in the form of 7 to 9 ft 
seas will spread in the offshore waters SW of the Baja 
California sur just west of the revillagigedo islands. Mixed 
swell to 10 ft along with fresh to locally strong winds will 
prevail in this zone through next weekend as the low pressure 
system continue to track west-northwest. Environmental 
conditions are conducive for development of this system, and a 
tropical depression is likely to form in a few days well off the 
coast of Mexico. The latest tropical weather outlook gives a 
high chance of development for this system within the next 5 

Moderate northwest flow is forecast west of the Baja California 
through Wed night, except becoming a fresh northwest breeze 
within 90 nm of the coast during the late afternoons and 

Gulf of california: light to gentle variable winds are forecast 
across the Gulf waters through Thu night, except for locally 
moderate southerly winds N of 29n.

Gulf of tehuantepec: fresh to locally strong nocturnal flow 
forecast through late Mon, then resuming on Mon night through 
Thu night with seas building to 10 ft downstream near 15n95w.  

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 N of the monsoon 
trough which is meandering between 09n and 12n. Moderate 
southwest flow is forecast S of the monsoon trough through the 
middle of the week, increasing to moderate to fresh southwest 
monsoonal flow from 06n to 10n between 109w and 115w on Mon 
morning as a surface low develops near 13n105w.  

Remainder of the area...   

A trough extends from 19n131w to 09n134w with isolated moderate 
convection flaring within 210 nm west of the trough.
The trough will move west of the area by early Tue.

A broad ridge continues across the subtropics accompanied by 
moderate to locally fresh anticyclonic flow south of 23n west of 



View All Hurricanes and Tropical Cyclones

Category 6

Welcome to Category 6. This is the collective home for Weather Underground's featured writeups by Dr. Jeff Masters (right), Bob Henson (left), Chris Burt, and other regular contributors.

Learn more about and the hurricane season in our hurricane archive.

View All Hurricanes and Tropical Cyclones

Hurricane Archive

All Atlantic Storms (1851-2018)

Named Storms for 2016

Historical Hurricane Statistics

Articles of Interest