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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 190301
TWDEP 

Tropical Weather Discussion  
NWS National Hurricane Center Miami FL
0405 UTC Mon Nov 19 2018  

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 0000 UTC surface analysis and satellite imagery through 
0300 UTC.

.SPECIAL FEATURE...

Gulf of Tehuantepec Gale Warning: Strong to near gale force 
northerly winds will pulse across the gulf waters and as far S 
as 13.5N96W through late Tue. Stronger drainage flow on Tue 
evening will result in minimal gale force conditions developing 
and continuing through mid morning on Wed.

.INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough extends SW off the Pacific coast of Colombia 
at 07N78W across the southern Gulf of Panama then turns NW to 
the Pacific coast of Costa Rica at 09N84W, then turns SW again 
to 07N101W where scatterometer winds indicate a transition to an 
ITCZ, which then continues NW interrupted by a 1011 mb surface 
low at 10N122W. The monsoon trough then wiggles W to another 
1011 mb low pres at 09N133W.

Scattered moderate isolated strong convection is noted N of 03N 
E of 79W, within 150 nm either side of a line from 10N116W to 
07N123W, and within 75 nm 09N132W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 

See Special Feature section for Gulf of Tehuantepec Gale Warning.

Gulf of California: Light and variable winds currently observed 
will become a moderate NW breeze briefly on Mon morning, then 
the pressure gradient will relax with light NW flow forecast 
through Wed, except light and variable winds expected over the 
northern waters as a weak front passes.  

A 1018 mb surface high is meandering near 26N120W with a ridge 
extending across the Mexican offshore waters W of 97W, with 
gentle to locally moderate anticyclonic flow forecast around the 
meandering ridge through the middle of the week, except a weak 
cold front will shift E across the waters N of 28N on Wed 
accompanied by a light and variable wind shift. 

Long-period NW swell, in the form of 7 to 9 ft seas, will arrive 
at 30N120W late Thu, and reach the northern coast of the Baja 
Peninsula early Fri. 

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

Gulf of Papagayo...Fresh to locally strong NE winds, with seas 
building briefly to 8 ft well downstream near 10.5N87W, are 
expected this week.  The strong winds will extend as far SW as 
10.5N88.5W.

Light to locally moderate northerly flow is forecast elsewhere N 
of the monsoon trough, while moderate southwesterly monsoonal 
flow, with 4 to 6 ft seas, is forecast S of the monsoon trough 
through the middle of the week.

REMAINDER OF THE AREA...  

A 1011 mb surface low is analyzed at 10N122W and another is 
analyzed at 09N133W. These lows will continue W accompanied by 
fresh E wind and seas to 8 ft through early Wed.  

A cold front extends from 32N128W to 22N138W accompanied by a 
fresh SW-W-NW wind shift, and 7 to 10 ft seas W of the front in 
long-period NW swell. Although the front will weaken, it will 
reach the Baja Peninsula on Wed evening. The associated NW swell 
will subside to less than 8 ft on Mon night. A second cold front 
will move into the area on Mon followed briefly by NW swell, in 
the form of 6 to 8 ft seas. 

A tightening pressure gradient will result in strong W winds N 
of 30N between 125W and 140W on Tue night into Wed. A ridge will 
set up from 29N140W to 18N106W on Wed night with strong NE 
trades, and seas to 11 ft, forecast from 11N to 22N W of 127W on 
Thu, surrounded by NW swell resulting in 7-9 ft seas across the 
waters elsewhere N of the ITCZ W of 120W.

$$
Nelson