000
AXPZ20 KNHC 210939
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
813 UTC Tue Jun 21 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.

..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...         

The monsoon trough axis extends from 10N85W to 08N94W to 10N100W
to 09N107W. The intertropical convergence zone axis extends from
09N107W to 07N120W to 09N127W to 06N140W. Scattered moderate
convection is within 150 nm south of the monsoon trough and 120 nm
north of the monsoon trough between 90W and 100W.

...DISCUSSION...   

North of 15N east of 120W:

A surface trough reaches from 32N117W to 27N118W. Another trough
extends from 1003 mb low pressure centered over the Colorado River
valley to the northern Gulf of California near 31N114W. Moderate
to fresh southwest winds were noted over the far reaches of the
Gulf of California earlier, to the east of the trough axis.
Gentle to moderate flow prevails elsewhere. Long period southwest
swell will move to the north of 15N through the early part of the
week.

The pressure gradient between high pressure building over the
Gulf of Mexico and lower pressures within the monsoon trough over
the eastern North Pacific is supporting strong gap wind flow
through the Gulf of Tehuantepec this morning. The mix of shorter
period wind waves from the gap winds with the longer period
southwest swell will result in areas of confused seas in and
downstream of the Gulf of Tehuantepec. In addition, the swell will
bring the potential for hazardous surf along exposed areas of the
coast of Mexico through the entire week.

South of 15N east of 120W:

Mainly moderate monsoonal flow prevails to the south of the monsoon
trough, while gentle to moderate northeasterly trade winds prevail
to the north of the monsoon trough, except locally fresh to strong downwind
of the Gulf of Papagayo this morning. Southwesterly swell is in
the 5 to 8 foot range is within 250 nm offshore, and in the 7 to
10 foot range beyond 250 nm offshore. A new set of long period
southwesterly swell moving into the area will build wave heights
to 6 to 9 feet across the entire area through tonight, then to 7
to 10 feet Tuesday and Tuesday night through the end of the week.
This swell will create the potential for hazardous surf along
exposed areas of the Central American coast. Seas will finally
start to subside Friday and Friday night from south to north.

West of 120W:

A surge of northerly winds off the coast of Southern California
is pushing south of 32N, and will bring fresh winds as far south
as 24N between 120W and 130W, with seas of 7 to 9 feet through
mid week. These conditions will persist through the end of the
week. Elsewhere the pressure gradient between high pressure
anchored to the north of the region, and low pressure within the
monsoon trough and in the vicinity of the ITCZ is supporting
moderate to fresh winds, with combined seas in the 4 to 7 foot
range, except 7 to 9 feet near the equator. The ridge will
prevail in the northern waters during the next few days with these
general conditions persisting. Global models indicate a weak low
pressure area forming along the monsoon trough near 120W by late
Thursday and drifting westward.

$$
Christensen