000
AXPZ20 KNHC 120311
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Sat Jan 12 2019

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 
0200 UTC.

...SPECIAL FEATURES...
The San Cristobal Volcano in NW Nicaragua near 12.7N87.0W was 
emitting ash and steam during this past afternoon. Satellite 
imagery showed a narrow ash plume moving SW away from the 
volcano and out over the local waters to near 11N90W, creating a 
narrow plume about 30 nm wide. However, since this time, a plume 
of ash is no longer evident in satellite imagery, and emissions 
from the volcano have diminished this evening. Mariners should 
exercise caution across this area, as intermittent emissions of 
ash and steam will remain possible over the next few days.

.INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
A surface trough extends from the coast of Colombia near 
04.5N77W TO 01N83W TO 06N88W TO 05.5N97W. The ITCZ continues 
from 04.5N77W TO 01N83W TO 06N88W TO 05.5N97W to beyond 05N140W. 
Widely scattered moderate convection is observed from 04N to 08N 
to the west of 133W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 

A small and weak ridge, centered on a 1018 mb high pressure near 
25N119W, continues to dominate the waters west of Baja 
California, and is producing gentle to moderate N winds across 
nearshore waters of Baja California, and variable winds 10 kt or 
less across the outer waters. Large NW swell dominating the 
regional waters the past 36 hours is subsiding from north to 
south across the waters of Baja California, with seas of 8 to 10 
ft south of 27N and 6-7 ft north of 27N. Seas will continue to 
subside overnight, falling to 5-7 ft by Sat morning. Another 
round of NW swell is expected to reach the northern coast of 
Baja California Norte and Guadalupe Island by Sat afternoon in 
association with the next cold front approaching 120W this 
evening. This reinforcing long period swell event will cause 
seas to rebuild to between 7 and 10 ft for the waters adjacent 
to Baja California by Sun afternoon.

Gulf of California: Gentle NW winds will cover most of the Gulf 
tonight beneath weak ridging overhead. Winds will then become 
variable less than 10 kt Sat and Sat night. A weakening cold 
front will move across the region from the west late Sat and Sat 
night. This will bring brief moderate to fresh westerly gap 
winds into the northern Gulf of California along 30N. 

Farther south, the long period NW swell continues to propagate 
through the Mexican offshore waters W of 95W. Variable winds of 
10 kt or less prevail south of 20N to the waters offshore of 
Puerto Angel, with seas of 6-9 ft. This NW swell is mixing with 
shorter period NE swell emerging from the Gulf of Tehuantepec to 
create another area of seas 7-9 ft between the offshore waters 
south of Tehuantepec and 100W. This area of combined swell will 
decay and shift southward away from the Mexican offshore waters 
through Sun afternoon.

N gap winds have tapered off to around 25 kt this evening with 
seas to 8 ft across the Gulf this evening. Strong high pressure 
over the the western Gulf of Mexico is shifting E ahead of low 
pres moving E from the southern Rockies. Winds across 
Tehuantepec will increase briefly to around 30 kt then rapidly 
diminish to less than 20 kt by late Sat afternoon as winds in 
the Gulf of Mexico veer sharply to the south. The next Gulf of 
Tehuantepec gap wind event is forecast by the computer models to 
begin on Sat night, reaching gale force Sun night through early 
Wed.

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

Gulf of Papagayo: Fresh NE to E winds will prevail across the 
Gulf region, and become fresh to strong across and downstream of 
the Gulf of Papagayo each night through the weekend primarily 
from the nocturnal drainage flow.
  
Gulf of Panama: Moderate to fresh northerly winds downstream to 
near 05N with seas to 6 ft will continue through the weekend.

REMAINDER OF THE AREA...  

A cold front extends across NW portions of the discussion area 
from 30N122W TO 28N123W TO 22N140W this evening and will 
continue moving eastward and gradually dissipate across central 
Baja California and the adjacent waters by Sat evening. A new 
round of large, long period NW swell also accompanies the front. 
Seas behind the front are currently running 8-15 ft in NW swell. 
As the front progresses eastward, seas across NW portions behind 
the front will subside gradually to 9-12 ft on Sat. 

Elsewhere, long period NW swell persists across the region west 
of 105W. Moderate to fresh trade winds are evident W of 125W 
between the ITCZ and 15N. Fairly dry conditions continue, and 
little shower or thunderstorm activity is observed in the 
vicinity of the ITCZ.

$$
Stripling