000
AXPZ20 KNHC 191606
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Sat May 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 1200 UTC surface analysis and satellite imagery through 
1430 UTC. 
  
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough axis extends from 09N73W TO 11N92W TO 11N117W 
TO 09N128W. The ITCZ continues from there to low pres near 
08N132.5W 1010 MB to beyond 06.5N140W. Scattered to locally 
numerous moderate to strong convection is from 05.5N to 13N east 
of 112W. Scattered moderate to strong convection is from 10N to 
13N between 85W and 89W, and within 180 nm either side of trough 
between 112W and 128W. Widely scattered moderate to strong 
convection within 90 nm either side of ITCZ between 128W and 
140W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Moderate to fresh NW winds continue off the coast of Baja 
California this morning, where seas are generally 6 to 8 ft. 
Generally light and variable winds are noted over the Gulf of 
California, with slightly stronger westerly gap winds near low 
level areas over the peninsula. Light N to NW winds are noted 
farther south off the Mexican coast. The main forecast issue 
ahead will be the onset of long period SW swell in excess of 8 
ft moving into the open Pacific waters off Mexico. The swell 
will reach waters of southern Mexico by early Mon, and into the 
open waters off Baja California Mon night and Tue, mixing with 
NW swell off Baja California Norte.

 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 5-8 ft are forecast over the Gulf and 
nearby waters through mid week due to long period SW swell.

Gulf of Panama: Gentle to moderate S to SW winds are forecast 
through Wed 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. 

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 of 6-7 ft in building long period SW swell west of 
the Galapagos Islands are expected to propagate northward Sat 
through late Tue next week building to 9 ft Sat.

REMAINDER OF THE AREA...

A cold front is moving slowly across the eastern Pacific and has 
stalled across the far northwest corner of the discussion area 
this morning, from 30N136W to 27N140W. The subtropical ridge SE 
of the front remains weak as the front approaches the area, but 
it is strong enough to support moderate to locally fresh trade 
winds across the tradewind belt in the deep tropics. Seas are 8 
ft in pockets north of the monsoon trough/ITCZ in areas of fresh 
trade winds, generally from 10N to 22N to the west of 124W. The 
front will weaken as it begins to shift southeastward today. The 
ridge will build eastward in the wake of the dissipating front, 
allowing the areal extent of the tradewinds, and subsequently 
the areas of 8 ft seas to expand over the deep tropics. 
Meanwhile cross equatorial southerly swell continues to 
propagate into the region, with seas reaching 8 ft as far north 
as 10N between 95W and 125W early in the week. Various wave 
model guidance shows the large SW swell encompassing most of the 
region south of 20N and east of 120W by mid week. Meanwhile, 
weak 1010 mb low pressure along the monsoon trough near 132W 
will drift west through early next week. Fresh trade winds north 
of the low pressure may reach 20 to 25 kt with seas to 10 ft by 
early next week as the ridge to the north builds. No significant 
development is expected.

$$
Stripling