000
AXPZ20 KNHC 202122
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Sat Nov 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 1800 UTC surface analysis and satellite imagery through
2115 UTC.

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

The monsoon trough axis extends from northwestern Colombia to 
across southern Costa Rica to 10N85W to 07N96W and to 09N105W, 
where latest scatterometer data indicates that it transitions to
the ITCZ continuing to 09N105W to 11N113W to 11N123W to 08N130W 
and to beyond 09140W. Scattered moderate convection is seen 
within 60 nm south of the ITCZ between 119W-124W, also within
60 nm north of the ITCZ between 124W-125W and within 30 nm south 
of the ITCZ between 109W-115W.

OFFSHORE WATERS WITHIN 250 NM OF MEXICO

The earlier gale-force winds across the Gulf of Tehuantepec have
diminished to strong to near gale-force along with seas to 11 
ft. The gradient will slacken enough on Sun to allow for the 
winds to diminish slightly, however, beginning on Mon a re- 
tightening of the gradient is expected to boost winds back up to 
near gale-force, reaching to gale-force on Mon night. Elsewhere,
high pressure ridging, from well north of the area, extends 
southeast to the west of the Baja California peninsula. Gentle to
locally moderate winds prevail over the open waters off Mexico, 
with light to gentle winds prevailing over the Gulf of 
California. Seas are in the 4-5 ft range over the open waters off
Mexico, with 1-3 ft seas over the Gulf of California. 

For the forecast, beginning on Mon the gap winds across the Gulf
of Tehuantepec will pulse back up to near gale-force, reaching 
gale-force on Mon night and Tue as the pressure gradient between 
strong high pressure that will surge southward over eastern 
Mexico and lower pressure south of Mexico within the monsoon 
trough again tightens up. Fresh to strong northwest to north 
winds may briefly develop in the northern Gulf of California on 
Mon, then across just about the entire Gulf late in the week 
along with building seas. Moderate northwest to north winds are 
expected offshore Baja California Norte beginning Wed. Otherwise,
rather tranquil conditions are expected elsewhere through the 
period.

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

The earlier noted strong northeast to east winds in the Papagayo
region are presently mainly at fresh speeds. Otherwise, light to
gentle winds are noted north of the monsoon trough. Gentle to 
moderate southerly winds prevail south of the monsoon trough. 
Seas are in the 4-6 ft range over the waters south of Costa Rica,
and 5-7 ft over the waters north of Costa Rica except for higher
seas of 6-8 ft north of El Salvador due to a northwest swell 
originating from the Gulf of Tehuantepec region.

For the forecast, the fresh northeast to east winds in the 
Papagayo region will pulse back up to fresh to strong speeds 
once again early on Sun, then diminish back to fresh speeds in 
the afternoon. These winds will change little through the period,
except pulse to strong speeds on Tue and Wed. Gentle to moderate
winds will prevail across the rest of the area for the next 
several days. The northwest swell that is producing seas of 6-8
ft north of El Salvador will gradually lower through Sun night 
allowing for those seas to subside to 4-6 ft. These seas may 
build some again early next week as gale-force winds start up 
again in the Gulf of Tehuantepec region.

REMAINDER OF THE AREA...

Broad high pressure ridging covers the area north of about
16N. A surface trough extends from 17N133W to 10N135W. The 
pressure gradient between the area of high pressure and the 
surface trough is supporting fresh to strong winds, and seas
of 8 ft within an area confined from 11N to 13N and between
129W-133W. Moderate to fresh east winds prevail elsewhere from 
10N to 23N between 120W and 140W. Light to gentle winds are
noted elsewhere north of the ITCZ, while gentle to moderate 
southerly winds are south of the monsoon trough and ITCZ.
Per latest ASCAT pass, moderate to fresh northerly winds are 
just north of the area. Seas of 5-7 ft are observed over the 
waters within the moderate to fresh winds and just north of 30N
between 118W and 130W. Seas of 4-6 ft continue elsewhere.

For the forecast, the area of fresh to strong east winds between
the trough and the area of high pressure will diminish to fresh 
speeds by early on Sun, with seas to 8 ft in mixed swell.
 
$$
Aguirre