000
AXPZ20 KNHC 202134
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Mon Mar 20 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
2100 UTC.

...SPECIAL FEATURES...

The most recent scatterometer pass provided observations of
minimal gale force winds in the Gulf of Tehuantepec while an
altimetr pass indicated seas to near 12 ft. Currently, winds 
have diminished below gale force, but another pulse of minimal 
gale force winds is likely tonight with the assistance of the 
nocturnal drainage flow. Strong winds and high seas will persist 
through Thursday morning as high pressure in the Gulf of Mexico 
enhances drainage flow across the Isthmus of Tehuantepec into the
eastern Pacific Ocean.
 
Northerly swell generated by this gap wind event will continue to
propagate southward and mix with swell generated in the Gulf of 
Papagayo region as well as with cross equatorial southwest swell.
This will result in combined seas of up to 10 ft in waters from 
04N to 12N between 90W and 115W this afternoon and between 90W 
and 120W tonight. 

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

A trough stretches from 04N89W to 03N100W to 02N105W. The ITCZ 
extends from 02N105W to 03N120W to 03N140W. Scattered moderate 
convection is noted within 150 nm N of trough between 90W and 
98W. A second trough is within the ITCZ and extends from 09N112W
to 03N112W. Scattered moderate convection is seen on either side
of the trough from 05N to 09N between 110W AND 115W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

See the Special Features section for information on the Gulf of 
Tehuantepec gap wind event. 

A 1021 mb high pressure centered near 24N121W will maintain 
gentle to moderate northwest winds across the offshore waters 
west of Baja California through Wednesday with seas of 4 to 6 
ft. A weakening cold front is expected to push into northern Baja
California by late Wednesday. A tight pressure gradient will 
result between the front and high pressure building behind it. 
This will support fresh to strong NW winds off the Baja California
coast Wednesday night through Thursday night. Seas off Baja 
California will build to 8-10 ft during that period. Winds are 
forecast to also increase across the north and central Gulf of 
California with the frontal passage Wednesday evening through 
Thursday, and across the southern Gulf of California Thursday 
afternoon through Thursday night. Currently, marine guidance 
suggests SW-W winds of 20-30 kt and building seas of 5-6 ft
across the northern Gulf of California, and NW winds of 20-25 kt
and seas of 6-7 ft across the remainder of the Gulf. 

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

High pressure will prevail over the northwest Caribbean and Gulf 
of Mexico, which will allow for the continuation of fresh to 
strong gap winds across the Gulf of Papagayo through most of the 
forecast period with seas 8 to 9 ft. Fresh to strong north to 
northeast winds are also expected tonight in the Gulf of Panama 
and downwind to about 05N with seas less than 8 ft. Otherwise, 
light to gentle winds and combined seas of 3-5 ft are expected to
continue the next several days elsewhere.

REMAINDER OF THE AREA...

High pressure of 1021 mb located near 24N121W will remain nearly
stationary over the next 24 hours. A frontal trough is analyzed
from 30N128W to 20N138W. A cold front follows the trough and
extends from 30N132W to beyond 25N140W. This front will reach 
from 30N125W TO 22N140W Tuesday afternoon, and from 30N118W to 
23N122W Wednesday afternoon, then continue eastward into the 
Baja California peninsula by late Wednesday. Seas will build to 
11-12 ft across the NW waters in the wake of this front. A third
cold front is forecast to reach the northwest forecast waters 
early Friday morning, briefly producing fresh to strong winds N 
of 29N and building seas of 12-13 ft.

$$
GR