000
AXPZ20 KNHC 122152
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2053 UTC Wed Apr 12 2017

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
2145 UTC.

...SPECIAL FEATURES...

...Gulf of Tehuantepec Gale Warning...

The pressure gradient between the high pressure ridging surging 
down eastern Mexico and lower pressures present to the south of 
the Tehuantepec region will tightened enough tonight to support  
minimal gale-force north to northeast winds to develop across 
the Isthmus of Tehuantepec and funnel out across the Gulf in a 
narrow swath area within 30 nm either side of a line from 16N95W
to 15N95.5W. Seas associated with these wind conditions are in 
the 8 to 12 ft range. Strong to near-gale force north to 
northeast winds are within 45 nm either side of a line from 
16N95W to 14N96W with seas up to 9 ft. The winds then diminish 
to just below gale-force by Thursday morning as the gradient 
relaxes again, with fresh to strong northerly flow pulsing 
thereafter through the remainder of the week and the upcoming 
weekend, mainly at night with nocturnal drainage flow.
 
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

The Intertropical Convergence Zone extends from 05N105W to 
03N122W to 04N134W. Surface trough extends from 10N136 to 05N136W.
ITCZ resumes at 04N137W to beyond 03N140W. Scattered moderate/isolated
strong convection is within 240 nm north of the axis between 
116W and 128W. 

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

See the Special Features section for details on the Gulf of 
Tehuantepec Gale Warning.

A 1021 mb high center is analyzed at 26N128W, with a ridge axis 
extending from northwest to southeast across the offshore waters.
Moderate to fresh anticyclonic winds prevail along the Pacific 
coast of Baja with long period northwest swell contributing to 
combined seas of 6 to 9 ft. The pressure gradient between the 
ridge and troughing along Baja California will tighten by 
this evening increasing winds along Baja California Norte
to mostly the strong category. These winds are expected to
persist through Friday with combined seas of about 7 to 9 ft.
These conditions are also expected to expand westward to near
117W during this forecast time.

In the Gulf of California, light to gentle variable flow will 
then prevail through the week and into the upcoming weekend with 
seas mainly 2 ft or less, except 3 to 4 ft near the entrance to 
the Gulf.

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

In the Gulf of Papagayo, fresh to locally strong nocturnal 
drainage winds are expected to pulse through the week and the 
upcoming weekend. These winds may possible max out to near 25 kt
tonight, with seas expected to build to around 8 ft downstream 
of the gulf waters during and shortly after the pulsing 
conditions.

In the Gulf of Panama, moderate to fresh nocturnal northerly 
flow is expected during the overnight hours through the remainder
of the week and the upcoming weekend. Seas are expected to build
to a range of 5 to 7 ft downstream of the gulf waters.
  
Elsewhere, light to gentle winds and combined seas of 3 to 6 ft 
will prevail during the next several days.

REMAINDER OF THE AREA...

A weakening cold front is analyzed over the northwest portion of
the area from near 31N125W to 26N140W. A secondary front extends
from 31N134W to 28N140W. The weakening front will become
stationary and dissipate during the next 36-48 hours. The second
and stronger cold front will remain north of the area but its
associated northwest swell will move across the northern portion
of the basin. Seas up to 11 ft in northwest swell are forecast 
to be north of 19N west of a line from 32N121W to 26N127W to 
19N132W at that time. Wave model guidance indicates that these 
seas will slowly subside Friday.

Elsewhere, the ridge that extends from the 1021 mb high centered
near 26N128W southeastward to near 13N105W. The pressure 
gradient between the ridge and lower pressure in the tropical 
belt region has resulted in fresh to strong northeast to east 
winds from 06N to 14N west of 123W, with seas 9 to 11 ft. 
Elsewhere from 05N to 17N west of 117W, winds are generally in 
the fresh range. Seas of 8 to 9 ft in mixed northeast trade wind 
produced swell mixing with long-period northwest swell are found
within this area. The fresh to strong northeast to east winds 
will weaken to fresh winds by early this evening as the 
aforementioned second cold front helps break down the ridging in 
place some. These conditions will vary little through Friday.
  
$$

NATIONAL HURRICANE CENTER