000
AXPZ20 KNHC 200909
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Mon Sep 20 2021

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 0600 UTC surface analysis and satellite imagery through
0900 UTC.

...TROPICAL WAVES...

The axis of a tropical wave is along 100W and N of 06N, moving 
west at 10 to 15 kt. Scattered moderate convection is noted from 
07N to 14N between 93W and 103W.

The axis of a tropical wave is along 108W from 07N to 20N, moving
west at 10 to 15 kt. Scattered moderate convection is noted from
05N to 12N between 105W and 112W.

The axis of a tropical wave is along 121W from 07N to 17N, 
moving west at around 10 kt. Scattered moderate convection is 
noted from 07N to 10N between 120W and 124W. 

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

The monsoon trough extends from 10N86W to a 1011 mb low pressure
near 12N114W to 09N121W to 11N130W. Aside from the convection
associated with the tropical waves, scattered moderate convection
is from 04N to 10N between 81W and 90W, from 07N to 17N between
110W and 120W, and from 06N to 18N between 130W and 138W. 

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Scattered showers and tstms are over the offshore waters between
Jalisco and the Revillagigedo Islands, extending to the Nayarit
adjacent waters. This shower activity is associated with an area
of low pressure over west-central Mexico and the northern portion
of a tropical wave. Latest scatterometer data show gentle to
moderate NW winds across the waters west of Baja California where
seas remain in the 4 to 6 ft range in mixed swell. Light to 
gentle variable winds are noted elsewhere offshore of SW Mexico 
with seas in the 3 to 5 ft range. Moderate SE winds are in the
northern Gulf of California with seas to 2 ft. 

For the forecast, NW swell will build seas west of Baja 
California Norte tonight through Tue in the vicinity of a 
frontal boundary that will dissipate by midweek. A Gulf of 
Tehuantepec gap wind event will begin Tue night and may bring 
near-gale conditions Wed through Fri night.

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

Latest scatterometer data continue to show moderate offshore 
winds in the Papagayo region and moderate to locally fresh S-SW 
winds mainly south of 08N. Long period SW swell continue to
support seas in the 5 to 6 ft range across the equatorial 
waters, and 4 to 5 ft across the Central American waters. 

For the forecast, long period SW swell across the region will 
start to subside by late Wed. Moderate to locally fresh winds 
will pulse in the Papagayo region through Tue. Otherwise, 
tranquil conditions should prevail through the end of the week. 

REMAINDER OF THE AREA...

A cold front transitions to a stationary front just to the N of 
30N. A broad surface ridge prevails south of the frontal boundary 
across the open waters north of the convergence zone. A 1010 mb 
low pressure area is along the monsoon trough near 12N115W, with
a surface trough extending northeast of the low to 16N112W. Recent
scatterometer data show moderate to locally fresh winds north of
the convergence zone to 20N and W of 112W, and moderate to fresh
SW winds south of the low to 04N between 109W and 118W. Altimeter
data show seas up to 9 ft in the vicinity of the low and in areas
of strongest convection. Seas to 7 ft are elsewhere S of the
convergence zone.

For the forecast, the frontal boundary will continue to weaken 
and completely dissipate tonight. Associated N swell will build 
seas to around 8 ft in the far north-central open waters. An 
area of low pressure is forecast to form several hundred miles 
SW of the southern tip of the Baja California peninsula within 
the next couple of days. Thereafter, some gradual development of 
this system is possible while it moves generally WNW through the
middle and latter parts of this week. Regardless of development, 
winds may increase to fresh to strong with seas to around 9 ft.

$$
Ramos