000
AXPZ20 KNHC 152157
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1921 UTC Thu Feb 15 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 1800 UTC surface analysis and satellite imagery through
2030 UTC.

...SPECIAL FEATURES...

Gulf of Papagayo Gale Warning: Strong NE to E winds will pulse 
to minimal gale force over the offshore Gulf of Papagayo waters 
from around sunset this evening until around sunrise Fri. A 
surrounding area of fresh to strong winds that touches the Gulf 
of Fonseca will also persist. Downstream seas will build to 8-11 
ft during the strongest winds tonight. This area of 8 ft seas 
has already merged with the area of 8 ft seas downwind from the 
Gulf of Tehuantepec. These areas will remain merged until Fri 
morning. Pulsing fresh to near gale force winds are then expected
each night thereafter through the weekend. 

Please refer to the East Pacific High Seas Forecast under 
AWIPS/WMO headers HSFEP2/FZPN03 KNHC for more details on the 
gale warning for the Gulf of Papagayo.

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

A surface trough extends from 05N85W to 05N100W to 06N112W. The 
ITCZ reaches from 09N129W to 07N135W to beyond 07N140W. No 
significant convection is currently associated with these 
features.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Gulf of Tehuantepec: High pressure ridging southward over the 
western Gulf of Mexico to the east of the Sierra Madre Oriental 
range, is no longer supporting gale force winds offshore and 
across the Gulf of Tehuantepec. The gale force winds have 
diminished as the ridging weakens, with a round of strong to near
gale force winds expected in association with nocturnal drainage
tonight, and then fresh to strong winds pulsing each night 
thereafter through Sun night.

Light and variable winds and seas of 2 ft or less this morning 
across the Gulf of California will become northerly while 
increasing to moderate to locally fresh through Fri as the 
pressure gradient tightens due to strong high pres to the NW. The
gradient will then weaken this weekend as the high weakens, 
allowing for conditions to improve. Looking ahead, a cold front 
will approach southern California and Baja California Norte by 
Sun night. SW flow ahead of the front will increase to 20-30 kt 
over the far northern Gulf Mon and Mon night. Fresh NW swell of 
6-8 ft will also propagate into the open Pacific waters W of 
Baja California Norte on Mon and Mon night.

Elsewhere across the open Pacific offshore waters of Mexico,
light to moderate winds will prevail through the next several
days, except pulsing to fresh offshore of Cabo Corrientes Fri
night through Sun. Seas will mainly be 4-6 ft in mixed southwest
and northwest swell.

Scattered showers associated with an inverted trough southwest of
the area will continue to advect NE across the waters north of 
20N ahead of an associated deep layer trough. 

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

Please see the Special Features section above for more details 
on the gale warning in the Gulf of Papagayo.

Discontinued Ashfall Advisory: The Fuego Volcano over S 
Guatemala near 14.5N 90.9W continues erupting. However, the plume
of volcanic ash advecting toward the W of the volcano is 
expected to stay over land in Guatemala and remain confined to 
within 60 nm of the volcano during the next 24 hours.

For the Gulf of Panama, winds and seas have begun to subside. 
fresh to strong N to NE winds will become moderate to fresh 
winds by Fri evening. Seas of 8 to 10 ft tonight will subside to
below 8 ft by Fri evening as well.

Elsewhere, gentle to moderate offshore flow will prevail north 
of 09N, and light to gentle SSW winds will generally prevail 
south of 09N.

REMAINDER OF THE AREA...

Low pressure measuring 1014 mb is centered near 18N126W with an 
associated surface trough extending from 18N126W to the low to 
11N127W. Scattered moderate and isolated strong convection 
associated with this system is occurring to the E of the trough
axis from 12N to 20N between 119W and 123W. This convection 
continues to plume off to the NE ahead of a deep mid to upper 
level trough that extends from 32N126W to 15N120W to 03N110W, 
and around a large upper-level anticyclone positioned over the 
Gulf of Mexico. A tight pressure gradient between the low and 
trough and high pressure centered well NW of the area near 
41N136W is supporting fresh to strong NE winds in the NW 
quadrant of the low within 270 nm, where seas are running 9 to 
11 ft.

The pressure gradient between the high and lower pressure 
associated with the ITCZ is also supporting fresh trades 
elsewhere west of these features generally between 15N and 25N to
beyond 140W. Seas are running 8 to 9 ft in mixed NE and NE 
swell. The low is forecast to dissipate within 24 hours. However,
the pressure gradient W of the trough will remain tight as the 
high pressure NW of the discussion area builds. Fresh to strong 
trades will expand and cover the waters from 15N to 30N west of 
120W by Fri evening. The gradient will then gradually weaken and 
allow the trades as well as any residual seas of 8 ft or greater 
to diminish by Sun evening.

$$
CAM