000
AXPZ20 KNHC 140656
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Sat Apr 14 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
0900 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning: Strong high pressure building  
southward along the Sierra Madre Oriental mountains and the
western Gulf of Mexico will allow for a very tight pressure 
gradient to set up over SE Mexico. Northerly winds at 20-25 kt 
will begin to surge into the Tehuantepec region by tonight, 
building seas to around 9 ft. Then, winds are expected to rapidly
increase to 30-40 kt by early Sun morning, and to 30-45 kt late 
in the afternoon. This event is expected to continue into early 
next week, while gradually diminishing. Seas as high as about 18 
or 20 ft are expected Sun night into Mon, before slowly subsiding
early next week. In adittion, an extensive swath of large NE to 
E swell will propagate well to the southwest and west of the 
Tehuantepec area, covering roughly the waters from 09N to 14N 
between 93W and 103W by early Mon morning. Climatologically speaking, 
the final gale force wind event occurs in the Gulf of Tehunatepec
in late March or early April. Please refer to the East Pacific 
High Seas Forecast under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for
more details. 

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

A surface trough extends from 10N85W to 07N95W to 05N103W. The 
ITCZ continues from 05N103W to 08N120W to 06N130W to 06N140W. 
Scattered moderate convection is noted within 120 nm N of ITCZ 
between 118W and 122W, and within 60 nm between 132W and 135W. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Moderate to fresh NW winds and large NW swell will prevail west 
of Baja California Norte today. A recent altimeter pass indicates
seas near to 13 ft across forecast zones PMZ001 and PMZ013. Seas
will gradually subside to 8-9 ft on Sun. Fresh to strong winds
and building seas of 8-10 ft are forecast across most of the 
Gulf of California through early Sun due to the presence of a 
strong high pressure over the Great Basin. A late season Gulf of
Tehuantepec gap wind event will be induced by a strong cold 
front moving across the Gulf of Mexico starting early on Sun. 
Please, see Special Features section above for details.

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

Light to gentle winds are expected through the forecast period. 
Seas in the 3 to 4 ft range will continue over most of the area. 
Fresh gap winds are likely in the Gulf of Papagayo tonight, and 
possible again early on Mon.

REMAINDER OF THE AREA... 

The pressure gradient between lower pressure in the vicinity of 
the ITCZ and strong high pressure of 1035 mb centered N of the 
area near 35N130W is producing fresh to strong trade winds north
of the ITCZ and west of 125W. The aerial extent of the trades
will diminish late on Sat as the high pressure weakens some. 
Large NW swell is propagating southeastward through the forecast 
waters, with max seas of around 14 ft in the north-central waters
based on latest altimeter data. This swell event will continue to
propagate SE across the forecast waters, particularly W of 108W
over the next 48 hours. A cold front will sweep into the NW
waters on Sun. Fresh to locally strong N to NE winds will follow
the front forecast to weaken over northern waters on Mon.

$$
GR