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Eastern North Pacific Tropical Weather Discussion (Text)



000
AXPZ20 KNHC 220908
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
417 UTC Wed Nov 22 2017

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 0600 UTC surface analysis and satellite imagery through
0945 UTC.

...SPECIAL FEATURE...

Gulf of Tehuantepec Gale Warning: Strong N winds will develop
this afternoon and quickly increase to 30 to 40 kt gale force
this evening, with these conditions continuing into early Thu 
afternoon. Minimal gale conditions will then persist through mid
morning on Fri. Winds will diminish to 20 kt or less late Sat
morning. Expect max seas of 17 ft near 14N96W late Thu. The 
resultant NE swell will propagate SW, mixing with long- period 
cross equatorial swell, with seas 8 ft or higher well downstream
of the Gulf of Tehuantepec along 09n between 96W and 104W on Fri
evening before beginning to subside. Strong N winds are forecast
to resume again on Sat evening with gale conditions at sunrise 
on Sun and continuing through sunrise on Tue. 

INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough extends W between 09N and 11N across the SW 
Caribbean to the Pacific coast of Panama and Costa Rica at 10N85W
and continues W to 09N100W where scatterometer winds indicate a 
transition to an ITCZ, which continues W to 07N114W to 12N140W
where it loses identity with a surface trough analyzed just W of
140W. Isolated moderate to strong convection is noted within 60
nm either side of a line from 08N81W to 07N89W, within 120 nm of
10N130W and 12N137W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

See Special Features paragraph above for information on the 
developing Gulf of Tehuantepec Gale Warning. 

A NW to SE orientated ridge extending about 250 nm seaward of the
Pacific coast of Mexico will be interrupted today as a trough 
forms extending SW from the central Baja Peninsula to near 
23N116W, and continues through Fri night before filling. Expect 
seas in the 2 to 4 ft seas at 12 seconds W of Baja through Thu 
morning, then building from the NW with 4 to 7 ft seas at 14 to 
15 seconds across the waters W of Baja on Fri night, subsiding 
some on Sat into Sun. Long-period NW swell in the form of 7 to 9 
ft seas will reach 30N120W on Sun night, and spread S across the 
waters W of Baja with 8 to 13 ft seas at 17 to 19 seconds 
forecast W of Baja late Mon night.

Gulf of California: Gentle to moderate NW flow expected through
Thu night. The pressure gradient will then relax, with light and
variable winds on Fri through Mon. Strong to near gale NW flow 
expected N of 30N on Mon night, with gale conditions possible on
Tue afternoon with seas building to 10 ft across the long fetch
waters.  

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

Gulf of Fonseca...Fresh NW winds forecast to begin around 
sunrise on Mon.  

Gulf of Papagayo: Fresh to locally strong NE nocturnal drainage 
flow forecast to begin on Thu night into early Fri afternoon, and
then resume on Fri night and continue through Tue with strong 
winds are expected to reach as far SW as 09N91W.

Light and variable winds, and 3 to 5 ft seas, are expected 
elsewhere through Sun to the N of the monsoon trough which has 
been meandering between 09N and 11N, while moderate southerly 
winds, and 3 to 6 ft seas, are forecast S of the monsoon trough.

REMAINDER OF THE AREA... 

A NE to SW aligned ridge will meander from 32N125W to 21N138W 
for the next several days. Scattered showers are possible under a
dense cirrus shield within 60 nm either side of a line from
30N133W to 25N137W. Strong SW winds, currently across the waters
N of 30N W of 135W, will diminish to 20 kt or less by this 
afternoon as the ridge weakens allowing a cold front to reach 
32N140W on Wed. The cold front will stall from 32N137W to 23N140W
on Thu with a surface low developing along the front near 
30N140W on Thu night. The low will move NE of the area late Fri 
night.

Combined seas of 8 to 13 ft currently across the discussion 
waters W of a line from 32N130W to 27N140W will build to 8 to 15
ft at 14 to 15 seconds late tonight. This long period NW swell, 
in the form of 8 to 11 ft seas at 12 to 17 seconds, will 
propagate across the waters W of a line from 32N122W to 14N140W
on Thu night before beginning to subside. 

Another cold front will move E in to the area reaching from 32N133W
to 25N140W early Sat with 8 to 14 ft seas at 12 to 17 seconds in
the wake of the front. 

$$
Nelson


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Page last modified: Wednesday, 22-Nov-2017 09:08:43 UTC