AXPZ20 KNHC 211529
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1529 UTC Thu Jun 21 2018
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
Based on 1200 UTC surface analysis and satellite imagery through
The axis of a tropical wave is analyzed N of 07N near 97W.
Scattered moderate and isolated strong convection is within an
area bounded by 16N94W to 09N95W to 07N98W to 09N102W to 12N103W
to 15N99W to 16N94W, including the Gulf of Tehuantepec. Westward
progress of this wave has started to slow as anticipated. This
wave will be one to watch with interest for potential tropical
development this weekend into early next week.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from 09N76W to 07N80W to 13N110W to
low pressure near 12N115W to 08N121W. The ITCZ extends from
08N121W to 07N127W to 09N137W. Scattered moderate isolated strong
convection is noted within an area bounded by 07N79W to 05N78W
to 04N85W to 06N87W to 08N85W to 07N79W, including the Gulf of
Panama, and also within an area bounded by 13N87W to 11N86W to
11N89W to 12N90W to 14N90W to 13N87W, including the Gulf of
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
Moderate NW winds west of the Baja California peninsula will
prevail through late today. A pulse of northerly swell will
propagate into the waters off Baja California Norte by the end of
the week, building seas to near 7 ft Saturday. Elsewhere, light
to gentle winds will prevail over the open waters the next
several days. Cross equatorial southerly swell will propagate
into the waters off Southern Mexico by the end of the week, which
will build seas to near 7 ft by Saturday. Seas will subside
Sunday into early next week.
Gulf of California: Winds will increase to moderate Friday, then
moderate to fresh in the southern Gulf and fresh to strong N of
29N by Saturday morning as the pressure gradient gradually
tightens. Seas will build to 4 to 7 ft as the winds increase,
except to 8 ft N of 29N. The wind will then diminish to light by
Monday with seas subsiding to 2 ft or less.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
The monsoon trough will meander between 09N and 11N the next
several days. Light to gentle winds will prevail N of the monsoon
trough, with gentle to moderate S to SW winds prevailing S of
the monsoon trough. A pulse of long period SW swell will reach
the waters W of Ecuador today, with combined seas building to 7
to 9 ft late Friday, except in the lee of the Galapagos Islands.
The swell will continue to spread across the southern forecast
waters, with seas building to 5 to 8 ft S of 08N early Sat. Seas
will subside on Sun and Mon.
REMAINDER OF THE AREA...
Low pressure of 1011 mb is centered near 12N115W. Scattered
moderate and isolated strong convection is within an area bounded
by 13N105W to 10N109W to 11N119W to 13N119W to 15N115W to
15N107W to 13N105W. This low will linger through the end of the
week, then may shift NE thereafter with possible deepening.
A trough is analyzed from 15N136W to 07N139W. Scattered moderate
and isolated strong convection is within an area bounded by 06N122W
to 03N123W to 03N128W to 06N138W to 09N139W to 10N136W to 06N122W.
Seas of 8 to 9 ft in mixed northerly swell are noted within an
area bounded by 20N140W to 20N136W to 15N131W to 13N136W to
20N140W. The trough will drift westward, moving west of 140W Fri
Elsewhere, high pressure of 1024 mb centered near 33N137W
extends a ridge SE to near the Revillagigedo Islands. Gentle to
moderate trades prevail west of 120W, where seas are in the 5 to
7 ft range. Seas N of 20N have subsided to 4 to 6 ft. A fresh
pulse of northerly swell will propagate into the northern waters
with seas building to 6 to 9 ft north of 25N between 120W and
130W Friday. Cross equatorial southerly swell will build seas to
6 to 9 ft south of 10N and west of 90W late Friday. Seas
associated to this swell will start to subside Sunday into early