000
AXPZ20 KNHC 170936
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
845 UTC Thu May 17 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 0600 UTC surface analysis and satellite imagery through
0930 UTC. 
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough axis reaches from 11N85W to 1010 mb low 
pressure near 11N119W to 06N130W. The intertropical convergence 
zone continues from 06N130W to beyond 02N140W. Scattered moderate
convection is noted within 120 nm in the northwest quadrant of
the low pressure, as well as from 04N to 09N between 115W and
120W. Scattered moderate to isolated strong convection is also 
noted from 05N to 10N between 93W and 100W. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Off Baja California, recent ship observations and a scatterometer
pass from 04 UTC indicate fresh to strong northerly winds, 
between 1022 mb high pressure centered west of the area and lower
pressure over northwest Mexico. Concurrent altimeter satellite 
data showed seas roughly 5 to 6 ft. An upper trough is moving
into southern California, and will clip Baja California Norte and
the northern Gulf of California later today and tonight. An
associated surface trough, or even a weak frontal boundary, will
develop north of the area today and move across the region north
of 28N later today and tonight. This will support pulses to 25 
kt north of Cabo San Lazaro tonight through Fri. Seas will reach
8 ft with the strong winds and a component of long period SW 
swell. Looking ahead, fresh NW flow will persist through the 
remainder of the period.

For the Gulf of California, moderate NW flow with 2 to 4 ft seas
will persist through late today. Fresh to strong westerly gap 
winds will pulse over the northern Gulf of California tonight in
the wake of a weak trough moving across the region. Little 
change is anticipated through the remainder of the period.

Farther south along the remainder of the coast of Mexico, weak 
northerly flow is noted. Seas are 5 to 7 ft with a component of 
SW swell. Showers and thunderstorm are active well to the south
of the Gulf of Tehuantepec beyond 250 nm along the monsoon trough.
This activity will persist on and off through early next week 
and may drift northward as the monsoon trough breaks with
moderate SW flow.
  
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR... 

Gulf of Papagayo: Light to gentle winds will dominate the gulf 
the entire forecast period as weak pressure will prevail across 
Central America. Seas of 4-7 ft are forecast over the Gulf and 
nearby waters through Tue.

Gulf of Panama: Gentle to moderate S to SW winds are forecast 
through Tue with seas of 4-6 ft in long period SW swell, 
building to 5-7 ft on Mon as the swell reaches the coasts of 
Panama and Colombia. Expect increasing wave action along those 
coasts.

Elsewhere, gentle to moderate SW winds are expected to the south 
of the monsoon trough with light to gentle variable winds north 
of trough as a weak pressure pattern remains over Central 
America. Seas are forecast to build to 6-7 ft in long period SW 
swell between Ecuador and the Galapagos Islands tonight and 
continuing through the weekend. Wave mode guidance indicates 
that these seas will build to 8 ft on Mon and will subside Tue.

REMAINDER OF THE AREA...

A 1022 mb high is centered near 28N128W, with a ridge axis 
extending southeastward to near the Revillagigedo Islands.
Farther south, 1010 mb low pressure is centered along the 
monsoon trough near 12N119W. Scattered moderate showers and 
thunderstorms are noted within 120 nm in the northwest quadrant
of the low pressure, and in convergent SW flow south of the 
monsoon trough from 04N to 09N between 115W and 120W. Gentle to 
moderate northerly breezes are noted north of 20N within the 
ridge, and moderate to fresh trade winds farther south to the 
monsoon trough. Stronger gusts are possible in the convection
near the low pressure. A series of recent altimeter satellite
passes indicate seas are reaching 7 to 9 ft in the area of fresh
trades, assisted by longer period SW swell. Farther south, 
additional altimeter passes showed seas 7 to 8 ft in a new group 
of SW swell reaching the equator. 

$$
Christensen