794 
AXPZ20 KNHC 181503
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Mon Sep 18 2023

Tropical Weather Discussion for the eastern Pacific Ocean from
03.4S to 30N, east of 120W including the Gulf of California, and
from the Equator to 30N, between 120W and 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.

...SPECIAL FEATURE...

A tropical wave extends its axis near 114W S of 17.5N, moving W 
at around 10 kt. Low pressure of 1007 mb is along the tropical
wave near 13.5N114W. Scattered moderate isolated strong
convection is noted within 120 nm in the W quadrant of the low.
Current associated winds are around 20 kt with seas to around 7
ft. Environmental conditions are expected to be conducive for 
gradual development during the next few days, and a tropical 
depression is likely to form by the middle or latter part of this
week while the system moves generally west-northwestward over 
the central and western portions of the basin. There is a medium
probability of tropical cyclone development with this system 
over the next 2 days, and a high probability of tropical cyclone 
development in the next 7 days. Please refer to the latest NHC
Tropical Weather Outlook at www.hurricanes.gov for more details.

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

The monsoon trough extends from 10N75W to 14N114W to 10N137W.
ITCZ from 10N137W to 09N140W. Scattered moderate isolated strong
convection is noted from 02N to 09N between 77W and 85W, from 
03N to 14N between 89W and 98W, and from 07N to 15N between 117W 
and 140W.

...OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

A surface ridge dominates the offshore forecast waters of Baja 
California supporting moderate to fresh NW winds and seas of 5-7
ft. In the Gulf of California, gentle to moderate winds prevail.
Seas are 2-4 ft, except 1-3 ft in the central Gulf. Fresh to 
strong N-NE winds are noted in the Gulf of Tehuantepec, along 
with seas of 5-8 ft. Light to gentle winds, and seas of 5-6 ft in
S to SW swell, prevail elsewhere across the Mexican offshore 
waters.

For the forecast, the surface ridge will remain in control of the
weather pattern across the region over the next several days.
Moderate to fresh NW to N winds will prevail over the waters
west of Baja California through the early part of the week, with
seas of 6-7 ft. Fresh to strong winds in the Gulf of Tehuantepec
will diminish Tue. 

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

Moderate to fresh gap winds are noted over and downstream of the
Gulf of Papagayo, with light to gentle winds elsewhere north of 
the monsoon trough. South of the monsoon trough, gentle winds 
prevail, reaching moderate speeds offshore southern Colombia and
between Ecuador and the Galapagos Islands. Seas are 4-6 ft, 
except 3-5 ft offshore Colombia, Panama and Costa Rica.

For the forecast, gentle to moderate southerly winds over the 
waters between Ecuador and the Galapagos Islands will prevail 
through mid week before diminishing. Moderate to fresh gap winds 
will prevail in the Gulf of Papagayo through Tue before 
diminishing slightly. Elsewhere, light to gentle winds will 
prevail. 

...REMAINDER OF THE AREA...

Refer to the Special Features section above for details on the 
developing broad area of low pressure along a tropical wave along
114W.

Moderate to locally fresh winds and seas of 6-8 ft are impacting
the waters from north of the monsoon trough/ITCZ to 22N and west 
of 120W. Gentle to moderate southerly winds are south of 04N 
along with seas of 5-8 ft in long period SE swell. Light to 
gentle anticyclonic winds and 4-5 ft seas are north of 25N and
west of 120W. Elsewhere, winds are moderate or weaker with seas 
of 4-7 ft. 

For the forecast, winds and seas will increase by the middle of 
the week in associated to the tropical wave discussed above. 
Elsewhere, high pressure will prevail across the northern waters,
particularly north of 15N and west of 110W. Under the influence 
of this system, gentle to moderate anticyclonic flow is expected 
with seas in the 4-7 ft range. NW swell of around 8 ft will drop 
just south of 30N between 120W and 135W by mid-week before 
decaying. South of 05N, moderate southerly winds will prevail, 
with moderate southerly swell persisting through the weekend.

$$
Lewitsky