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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 170912
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Fri Sep 17 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
0845 UTC.

...TROPICAL WAVES...

The axis of a tropical wave extends along 94W north of 05N, 
moving west at around 10 kt. Scattered moderate convection is 
noted N of 14N between 90W and 96W.

The axis of a tropical wave extends along 110W from 00N to 10N, 
moving west at around 15 kt. No significant convection is noted 
at this time with this feature.

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

The monsoon trough extends from 11N86W to 11N119W. The ITCZ 
continues from 11N119W to 11N140W. Aside from convection 
discussed in the tropical wave section above, scattered moderate 
convection is noted from 09N to 13N and E of 97W, and from 07N 
to 11N between 116W and 140W.

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Latest scatterometer data depicts gentle to moderate NW winds 
west of the Baja California peninsula. Seas remain in the 5 to 6 
ft range. Light to gentle variable winds and seas of 5-6 ft are 
noted elsewhere over the S and SW Mexico offshore waters with 
seas in the 5 to 6 ft range as indicated by recent altimeter 
data. In the Gulf of California, winds are also light to gentle 
and variable, with seas to 3 ft.

For the forecast, gentle to moderate winds, occasionally fresh, 
will prevail across the waters west of Baja California through 
Mon late in the afternoon, when winds will diminish to light to 
gentle. However, seas will remain in the 5 to 6 ft range due to 
long period SW swell combining with long period N swell early 
next week. SE winds will develop along the Gulf of California 
tonight and will continue through Fri night. Moderate southerly 
winds will resume along the gulf on Mon and diminish again Mon 
night. Otherwise, light to gentle variable winds will prevail 
elsewhere through Tue next week with seas to 5 ft.

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

Gentle to moderate southerly flow dominate across much of the 
forecast waters S of 10N with seas in the 6 to 7 ft range in SW 
swell. Light to gentle variable winds with 5 to 6 ft seas are 
over the remainder offshore zones N of 10N. 

For the forecast, SW swell across the region will subside today.
A second round of SW swell will move across the area during the 
weekend through early next week, which will sustain seas to 6 ft 
across the area with mainly moderate southerly winds S of 10N. 
Otherwise, moderate to locally fresh winds will pulse in the 
Papagayo region Fri through Mon.

REMAINDER OF THE AREA...

A surface trough extends from 28N123W to 25N127W. Surface ridging
is to the NW of this trough, which is supporting moderate to 
fresh NE winds N of the monsoon trough to nearly 24N. Seas are 
in the 5 to 6 ft range in this region. Gentle to moderate 
southerly winds dominate elsewhere S of the monsoon trough. Seas 
are generally in the 5-7 ft range.

Little change in the weather conditions is expected through the 
forecast period. A frontal boundary is expected to approach from
the NW and stall along 30N by late this weekend and linger in
this area through early next week. NW swell will build seas to 
around 8 ft along and near 30N just W of the Baja California 
offshore waters.

$$
ERA