AXPZ20 KNHC 231617
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Sat Jun 23 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
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from 10N75W TO 10N93W to a 1010 mb
low pressure near 14.5N105W to a 1007 mb low pressure near
12.5N116W to 09N122W. The ITCZ continues from 09N122W to 08N130W
to 10N140W. Scattered to locally numerous moderate to strong
convection noted within 240 nm of the coasts from Nicaragua to
Colombia. Otherwise, scattered moderate to strong convection is
from 04N to 09N between 91W and 100W, from 08N to 18N between
99W and 110W, from 09N to 14N between 112W and 120W and from 07N
to 15N W of 130W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
NW winds have diminished early this morning across the waters
west of Baja California, as a broad surface trough along the W
coast of the peninsula shifts westward across the NE Pacific
waters. Winds west of the peninsula will become variable less
than 15 kt through the weekend. However, southerly winds inside
the Gulf of California have increased quickly overnight, and are
forecast at 20-30 kt to the north of 30N this morning, and fresh
to strong elsewhere N of 26N this morning. Seas across this area
will increase to 6-9 ft later this morning through afternoon,
before winds and seas begin to slowly subside through late
Further south, long period cross-equatorial SW swell has moved
into the regional waters overnight and will affect the waters
from central Baja California to Central America through Monday.
5 to 7 ft seas off of Southern Mexico this morning will build to
6-8 ft by Sun morning before slowly subsiding late Sun night and
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
The monsoon trough will meander between 09N and 13N the next
several days. Light to gentle winds will prevail north of the
monsoon trough, with gentle to moderate S to SW winds expected
south of the trough axis. Long period cross-equatorial SW swell
is across southern forecast waters with seas to 8 ft. The swell
will propagate further north to the offshore waters of Costa
Rica and Colombia today and then will gradually subside through
REMAINDER OF THE AREA...
High pressure north of the area centered near 36N141W extends a
ridge SE to near the Revillagigedo Islands. Moderate to fresh NE
to E winds prevail west of 130W with seas generally ranging
between 5 to 7 ft. Gentle to moderate N to NE winds dominate the
remainder of the basin north of the monsoon trough and west of
120W. The high pressure center is forecast to shift NW and
reorganize, which will freshen winds N of 25N and to the west of
125W through Mon.
Typical northerly swell generated offshore of California is
propagating into the northern waters this morning, and will
build seas modestly to 8 ft north of 28.5N between 122W and 129W
late tonight before seas subside to 6-7 ft Sun afternoon. The
cross-equatorial southerly swell is also moving through the
tropical waters south of 20N and west of 120W this morning, and
will maintain seas 5-7 ft there through Mon.
A low pressure centered near 12.5N116W and embedded along the
monsoon trough has an estimated pressure of 1007 mb. Model
guidance shows this low emerging from the trough and drifting
northward with a gradual increase in intensity through the
weekend. Active thunderstorms will continue in the vicinity of
this low through early next week before the low moves across
cooler waters and begins to weaken considerably late Tue.
A 1010 mb low pressure is near 14.5N105W generating scattered
moderate convection from 09N to 18N between 98W and 110W. Global
models guidance indicate there is a good chance for this low to
develop into a tropical cyclone SW of Mexico early next week.