AXPZ20 KNHC 220915
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Sat Sep 22 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 0600 UTC surface analysis and satellite imagery through
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends W off the Caribbean coast of Colombia
at 10N75W, and continues west across the extreme southwest
Caribbean and across northern Costa Rica to the Pacific Coast of
Costa Rica at 11N85W to 09N106W TO 11N123W where it loses
identity. The monsoon trough resumes near 12N128W and extends
southwest to 11N140W. Scattered strong convection is noted
within 150 nm either side of a line from 13.5N89W to 12N98W.
Isolated moderate to strong convection is observed elsewhere
within the area bounded by 19N120W to 17N98W to 08N83W to
04N110W to 09N127W to 19N120W. Scattered moderate convection is
noted within 60 nm either side of a line from 10.5N130W to
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
A ridge extending from 22N116W to 15N100W will gradually retract
northwest as a surface low slowly develops near 13N106W on Sun
night, and then tracks northwest accompanied by tstms just
beyond 250 nm seaward. However, gentle to locally moderate
cyclonic winds will shift northwest through the offshore waters
mostly seaward of 200 nm with the low reaching a position near
18N115W on Fri.
Moderate northwest flow is forecast west of the Baja California
through early Mon, except becoming a fresh northwest breeze
within 90 nm of the coast during the late afternoons and
Gulf of California: Gentle to locally moderate variable winds
forecast across the gulf waters north of 30N through the
weekend. Otherwise, light to gentle variable winds expected
across the gulf waters through the middle of next week.
Gulf of Tehuantepec: Fresh to locally strong nocturnal flow
forecast tonight through Mon night, with a strong northerly
drainage event expected on Thu night with seas building to 9 ft.
The late week event may assist in the development of a surface
low near 12N95W late next week.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
Gulf of Papagayo: Moderate to locally fresh east nocturnal
drainage flow expected through Mon night.
Light and variable winds are forecast elsewhere N of the monsoon
trough which is meandering between 09N and 11N. Moderate
southwest flow is forecast S of the monsoon trough through the
middle of next week. Moderate to fresh southwest monsoonal flow
is expected south of 10N late next week as a surface low begins
to develop near 13N93W on Thu, and then tracks northwest of the
area on Fri accompanied by tstms.
REMAINDER OF THE AREA...
A trough extends southwest from 20N125W to 11N128W with isolated
strong convection flaring within 60 nm of the trough. The trough
will move west of the area by the middle of next week.
A broad ridge continues across the subtropics accompanied by
moderate to locally fresh anticyclonic flow south of 23N west of