000
AXPZ20 KNHC 212145
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2143 UTC Tue Mar 21 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.

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

The intertropical convergence zone axis extends from 05N90W to
02N110W to 05N122W to 03N140W. Scattered moderate and isolated
strong convection is within 180 nm north of the axis between 90W
and 104W, and between 109W and 116W, and also between 117W and
126W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

In the Gulf of Tehuantepec, the pressure gradient will remain
tight enough to support strong to near gale force gap wind 
pulses through the Gulf of Tehuantepec tonight and Wednesday 
night with the assistance of local overnight drainage flow. Seas 
will will fluctuate to the 9-11 ft range over the next couple of
mornings with the near gale force pulses. A smaller and quicker 
pulse of strong gap winds is expected Thursday night, with 
generally moderate flow thereafter. Northerly swell generated by 
this gap wind event continues to propagate southward mixing with 
swell generated in the Gulf of Papagayo region as well as with 
cross equatorial southwest swell. This is resulting in combined 
seas of up to 10 ft in waters just southwest of the offshore 
area which will continue through Wednesday night.

Elsewhere, a 1021 mb high pressure centered near 23N120W will 
maintain gentle to fresh northwest winds across the offshore 
waters west of Baja California through Wednesday evening with 
seas in the 4-6 ft range. A cold front is expected to push into 
northern Baja California by Wednesday night. A tight pressure 
gradient will result between the front and high pressure building
behind it, supporting fresh to strong northwest winds off the 
Baja California coast Wednesday night through early Friday 
morning. Seas off Baja California will build to the 6-9 ft range 
during that period. Winds will also increase across the north and
central Gulf of California with the frontal passage Wednesday 
night through Thursday, and across the southern Gulf of 
California Thursday afternoon through early Friday morning, with
seas to 8 ft in the southern Gulf of California, as well as 
west-southwest of the southern tip of the Baja California 
peninsula.

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 Friday with 
seas to 8 ft.

Fresh to strong northerly winds are also expected in the Gulf of
Panama and downwind to about 05N, with seas less than 8 ft 
through Wednesday morning. Otherwise, light to gentle winds and 
combined seas of 3-5 ft are expected to continue the next several
days elsewhere. Confluent low level flow is support moderate to 
strong convection along the ITCZ across the southern portion of 
the zones west of Ecuador.

REMAINDER OF THE AREA...

High pressure of 1021 mb located near 23N120W will move little 
over the next 24 hours. A cold front extends from 30N123.5W to
22N140W. This front will reach from 30N118W to 22N130W to 
19N140W Wednesday afternoon, then continue eastward into the 
northern Baja California peninsula and the northern Gulf of 
California through Thursday. Seas in the 8-12 ft range behind
this front will propagate southeast while decaying through the
next 24 to 48 hours or so. Another cold front is forecast to 
reach the northwest forecast waters Friday morning, followed by 
a new round of northwest swell. A third cold front may arrive by
Sunday night.

Farther south, combined seas in the 8-10 ft range cover the
waters along and north of the ITCZ. Scattered moderate to 
isolated strong thunderstorms are ongoing to the north of the 
ITCZ due to confluent flow in the lower levels, and enhancement 
aloft from an upper level trough to the west.

$$
LEWITSKY