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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 230242
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0230 UTC Thu May 23 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
0230 UTC.

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

The monsoon trough extends from the coast of Costa Rica near 
10N85W to 1010 mb low pressure near 11N87.5W to 10N100W to 
09N115W to 08N120W. The ITCZ continues from 08N120W to beyond 
07N140W. Scattered moderate convection is noted from 04N to 07N
east of 79W, within 150 nm SE quadrant of the low center, within
240 nm south of the trough between 94W and 108W, and within 90 
nm of the ITCZ between 133W and 138W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 

The pressure gradient between a high pressure ridge west of Baja
California and lower pressure across inland Mexico is supporting
moderate to fresh NW winds off the west coast of Baja California
based on recent ship observations and earlier scatterometer 
data. NW swell associated with stronger winds off California is
producing 8-12 ft seas north of Cabo San Lazaro tonight. Peak
seas are expected to reach 13 ft over the far outer offshore waters
later tonight, and seas greater than 8 ft will persist across the
region through Fri before the swell decays.

Elsewhere, earlier scatterometer data showed fresh NW winds west
of Cabo San Lucas off the southern coast of Baja California Sur.
Moderate to fresh winds will likely persist into early Thu before
diminishing.

Gulf of California: Strong to near gale force SW to W gap winds
will continue tonight over the Gulf of California north of 29.5N.
Expect building seas to 8 ft late tonight over the northern Gulf
before wind speeds quickly diminish on Thu as the pressure
gradient relaxes over the region. Looking ahead, another strong
to near gale force SW gap wind event is expected Sat night into 
Sun ahead of a cold front approaching the region.

Gulf of Tehuantepec: Fresh to strong northerly winds will pulse
across the Gulf of Tehuantepec this weekend. Seas will build to
8 ft within the strongest winds during the overnight and early 
morning hours.

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

A low pressure system located very near the west coast of Nicaragua
is producing an area of showers and thunderstorms. This system 
is expected to continue to meander near the coast of Central 
America during the next few days, and gradual development is 
possible during that time if the disturbance remains offshore. 
Even if development does not occur, locally heavy rains are 
likely over portions of Central America during the next few days.
These rains could cause flash flooding and mudslides in areas of
mountainous terrain.

Otherwise, the monsoon trough will dominate the regional pattern
into early next week. Expect generally light to gentle winds north
of the monsoon trough and moderate to fresh S to SW winds south 
of the monsoon trough through the weekend. Early next week, the 
global models suggest strong winds may develop south of the trough,
although this depends on how the low pressure system described 
above evolves in the coming days. Seas generally will run 8 ft or
less into the weekend, then build into early next week in response
to the strengthening monsoon flow.

REMAINDER OF THE AREA... 

Northwest swell over the waters north of 20N and east of 130W is
producing seas greater than 8 ft across the region with 12-14 ft
seas supported by a 2220 UTC altimeter pass northwest of Guadalupe
Island. This swell will gradually decay by Fri with seas falling
below 8 ft Fri night into Sat.

A high pressure ridge extends from a 1033 mb high near 38N138W 
east-southeastward to near the Revillagigedo Islands. The pressure
gradient between the ridge and the ITCZ is maintaining fresh trades
over the waters west of 130W. Earlier altimeter data showed 7-9 
ft seas in mixed SW and NW swell and NE wind waves extending from
30N133W to 10N131W. 

Elsewhere, a small area of 8 ft seas in SW swell persists roughly
from 06N to 09N between 107W and 113W. A pulse of cross-equatorial
SW swell will result in 8 ft seas developing by Thu over the waters
generally south of the Equator and west of 100W and spreading 
northward through Fri. 

$$
Reinhart