AXPZ20 KNHC 200128
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
105 UTC Thu Jun 20 2019
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 0000 UTC surface analysis and satellite imagery through
A tropical wave with axis along 99W from 04N to 15N is moving
westward at 10-15 kt. Scattered moderate convection has developed
with this wave from 05N to 10N between 90W and 99W.
A tropical wave with axis along 122W from 04N to 15N is moving
westward at 15 kt. Scattered moderate convection exists from 05N
to 15N between 115W and 125W.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough axis extends from a 1007 mb low over
northern Colombia westward to 09N79W to 08N95W to 13N111W, to where
it transitions to the ITCZ to 10N130W. The ITCZ then continues
through 10N140W. Outside of convection discussed above under
the Tropical Waves section, scattered moderate convection exists
within 120 nm of the trough between 79W and 90W, and from 125W to
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
Afternoon scatterometer data continue to show gentle to moderate
northwest wind across offshore waters as weak high pressure
dominates E of 135W. Altimeter satellite passes at both 16 UTC
and 18 UTC indicated seas of 7 to 8 feet were being observed 120
NM and greater offshore Baja California Norte, with lesser seas
elsewhere. These higher seas deriving from gales off the western
coast of the United States, and will continue as northerly swell
impacts the region through the remainder of the week. Elsewhere,
the high pressure will remain in control, keeping little changes
from occurring. Low pressure over the Colorado River Valley will
strengthen some Friday, and a surface trough will continue to
extend from this low over Baja California. This will cause winds
to increase over the northern Gulf of California, possibly
reaching to near gale force on Fri night. Farther south, a weak
tropical wave will move west across the southern Mexico offshore
waters, with little impact on local weather, aside from enhancing
overnight coastal showers and thunderstorms.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
Gentle to moderate breezes will prevail over most of the water
into the weekend. However, pulses of wind of 20 to 25 kt is
expected during the overnight hours tonight, and again Friday
night into early next week in the area near Papagayo. These gap
winds are due to a tight pressure gradient between high pressure
north of the Caribbean sea and the lower pressure associated with
the monsoon trough. Altimeter satellite scans from 14 UTC show
Seas of 4 to 6 FT will prevail as southerly swell will continue
to be dominant into the weekend.
REMAINDER OF THE AREA...
A 1033 mb high remains quasi-stationary well north of the area
near 40N140W, with a ridge extending southward to the tropical
region west of 120W. South of this ridge, easterly wind of 15 to
20 kt is occurring, and these trade winds should persist through
the weekend. North of 26N, seas of 8 to 10 feet are occurring,
according to an 18 UTC altimeter satellite scan, due to
northerly swell forming in gales off the west coast of the United
States. This swell will continue for the next several days.
Farther south, long-period cross-equatorial swell is causing seas of
8 to 9 feet. This swell will decay some toward the end of the
week, before new swell arrives this weekend, again increasing
seas south of 08N to 8 to 10 feet.