AXPZ20 KNHC 210330
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
202 UTC Tue Aug 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 0000 UTC surface analysis and satellite imagery through
A tropical wave along 96W is moving W around 15 kt. Scattered
moderate and isolated strong convection is present from 06N to
11N between 93W and 97W.
A tropical wave along 116W-117W is moving W around 10 kt.
Scattered moderate and isolated strong convection is found from
07N to 14N between 111W and 120W.
A tropical wave along 128W-129W is moving W around 5 kt.
Scattered moderate and isolated strong convection is seen within
60 nm either side of a line from 17N125W to 13N134W.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from 11N74W to 08N98W to 11N115W to
12N125W. The ITCZ extends from 10N133W to beyond 09N140W.
Scattered moderate and isolated strong convection is observed
from 07N to 11N between 98W and 107W and from 07N to 11N between
W of 133W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
A surface ridge across the NE Pacific extends SE from a 1030 mb
high near 45N138W to enter the forecast waters near 32N130W,
then onward to near the Revillagigedo Islands. This ridge will
support a weak to modest pressure gradient across the offshore
waters of Baja California. Gentle to moderate NW winds are
expected through Wed before the ridge strengthens slightly and
the pressure gradient tightens across Baja California Norte Thu
and Fri. Seas will generally remain in the 4-5 ft range through
Wed. Surface troughing over the Baja Peninsula will maintain a
generally light wind regime over the Gulf of California through
Sat night, and allow for afternoon sea breezes and nocturnal
land breezes to dominate.
Strong N to NE gap winds will affect the Gulf of Tehuantepec Tue
night through Thu night, and are forecast to peak near 30 kt
late Wed night. Seas of 4 to 6 ft during the daytime could build
to near 8 ft each of these nights, and 8-10 ft late Wed night.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
The monsoon trough will linger near 09N during the next few
days. Winds on both sides of the trough axis will generally be
light to moderate. The main exception to this will be over the
Gulf of Papagayo, where moderate to fresh offshore winds will
pulse to locally strong each night. Seas are expected to remain
6-7 ft downstream of Papagayo during this time.
REMAINDER OF THE AREA...
Elsewhere, the pressure gradient between ridging across the
northern waters and the ITCZ will support gentle to moderate
trades and 4-7 ft seas in mixed swell N of the ITCZ and W of
120W through the middle of this week.
Sea heights will be relatively low for most of the forecast area
this week. Mixed SE and SW swell has produced 8 ft seas S of 02S
and W of 112W. This area of seas will continue until Tue morning
before subsiding to less than 8 ft. A much more robust round of
long period swell could arrive from the Southern Hemisphere
toward the end of this week and cause seas near the Equator to
begin building on Sat.