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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 010933
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
930 UTC Fri Jul 1 2016

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.

...TROPICAL WAVES...

A tropical wave moving west across the Gulf of Panama this
morning is enhancing overnight convection over eastern Panama and
off the Pacific coast of Colombia. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough reaches from 10N85W to 1011 mb low pressure
centered near 09N94W to 1011 mb low pressure near 11N106W to 1011
mb low pressure near 13N116W to 1011 mb low pressure near 13N135W
then southwestward to beyond 08N140W.

Numerous moderate to scattered strong convection is noted off the
coast of Colombia, eastern Panama, and Costa Rica. Scattered
moderate to isolated strong convection is noted within 120 nm of
the center low pressure near 09N94W. Scattered moderate convection
is noted within 120 nm in the southwest semicircle of the low
pressure centered near 11N106W. Scattered moderate to isolated
strong convection is noted within 120 nm in the northwest quadrant of
the low pressure centered near 13N116W. 

...DISCUSSION...   

North of 15N and east of 120W:

A recent altimeter pass indicated wave heights to 8 ft off the
coast of Baja California Norte. This is northerly swell generated
by persistent strong winds off the coast of California, the result
of a tight pressure gradient between 1032 mb high pressure
centered northwest of the area and 1006 mb low pressure over the
Central Valley of California. The 8 to 9 ft swell will recede
westward today, generally staying west of Guadalupe Island and
north of 26N through late Saturday. Meanwhile a surface trough
will persist along the Baja California peninsula through at least
Sunday, supporting moderate to occasionally fresh southerly flow
over the northern Gulf of California. Looking ahead, the low
pressure centered near 11N106W is expected to gradually deepen
through late Sunday as it moves west-northwest along the monsoon
trough. This may bring strong winds and seas of 8 to 9 ft to the
area from 15N to 17N to the south of the Revillagigedo Islands
from late Sunday through early Tuesday. 

South of 15N and east of 120W:

The monsoon trough remains very active this morning, with a series
of low pressure systems along the trough axis between 95W and
120W. Model guidance is consistently showing further development
of one or more of these low pressure areas, but continues to be
inconsistent regarding the details such as when, where and to what
extent. While some organization is noted primarily in the mid
levels of the atmosphere and primarily concerning the low
pressure area centered near 11N106W, the showers and thunderstorms
around the low pressure have not persisted long enough for
sustained further development. Recent altimeter passes indicated
wave heights of 7 to 8 ft south of the monsoon trough between 90W
and 105W, due in part to longer period southwest swell. Seas to 8
ft are also noted within 90 nm of the low pressure centers near
11N106W and 12N116W. The normal overnight increase in gap winds
across the Gulf of Papagayo will be enhanced slightly early
Saturday morning with the assistance of a passing tropical wave.
Looking ahead, the low pressure centered near 11N106W is expected
to gradually deepen through late Sunday as it moves west-northwest
along the monsoon trough, with 20 to 25 kt within 150 nm in the
northern quadrant of the low pressure, and seas building to 8 to
10 ft.

West of 120W:

A broad ridge dominates the region north of 15N and west of 120W.
Recent altimeter passes indicates wave heights of 8 to 9 ft over
much of the area north of 25N. This is largely due to northerly
swell generated from persistent strong winds off the coast of
California. Various wave guidance indicates seas of 8 to 9 ft will
cover the region north of 15N and west of 125W through early
Sunday, before decaying to less than 8 ft over most this region
through Monday. The low pressure area centered near 13N116W along
the monsoon trough will shift west-northwest reaching near 16N125W
by Monday with 20 to 25 kt winds and seas to 9 ft within 120 nm of
the northern semicircle, then weaken through Tuesday. Otherwise
generally moderate trade winds will persist through south of 20N
into early next week.

$$
CHRISTENSEN