AXPZ20 KNHC 192120
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2007 UTC Wed Jun 19 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 1800 UTC surface analysis and satellite imagery through
A tropical wave with axis along 97W from 04N to 15N is moving
westward at 10-15 kt. No significant convection is associated
with this wave.
A tropical wave with axis along 119W from 04N to 15N is moving
westward at 15 kt. Convection consists of the scattered moderate
to isolated strong type within 120 nm east and west of the wave
from 04N to 14N.
...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, numerous moderate to strong
convection is noted within 150 nm south of the trough between 79W
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
Afternoon scatterometer data continues to show gentle to moderate
northwest wind across offshore waters as weak high pressure
dominates E of 130W. Altimeter satellite scans from 14 to 16 UTC
show seas are 4 to 5 feet, except for waters offshore Baja
California Norte, where seas of 5 to 7 feet are observed. These
seas are 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...
Midday scatterometer data revealed gentle to moderate breezes
across offshore waters. Winds have diurnally diminished near the
Papgayo region, but are expected to increase again overnight to
20-25 kt. This pulse is due to a tight pressure gradient between
high pressure north of the Caribbean sea and the lower pressure
associated with the monsoon trough. This gradient will persist
and these gap winds will continue each night into the weekend.
Altimeter satellite scans from 14 UTC show that seas of 4 to 6
feet are common, and these seas 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 9 feet are occurring,
according to 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, indicated on multiple earlier day altimeter
satellite passes south of 08N. 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.
KONARIK/NATIONAL HURRICANE CENTER