Tropical Weather Discussion
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AXPZ20 KNHC 170949

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
731 UTC Thu Aug 17 2017

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
meteorological analysis.

Based on 0600 UTC surface analysis and satellite imagery through
0830 UTC.


A tropical wave extends N from 11N87W to 23N85W. This wave is
moving westward around 15 kt during the past 24 hours. Short term
model diagnostics show subtle troughing at 700 mb in conjunction
with this wave. TPW satellite imagery shows this wave is
embedded in an area of deep layer moisture, but no significant
convection is currently associated with this wave.

A tropical wave extends from 11N105W to 18N105W. The wave has
moved W around 10 kt during the past 24 hours. The wave
coincides with a well defined 700 mb trough in short term model
guidance. TPW satellite imagery shows this wave is embedded in
an area of deep layer moisture. Scattered moderate and isolated
strong convection is found from from 07N to 10N between 100W and
105W and from 16N to 19N between 105W and 108W.


The monsoon trough extends from 10N74W to 08N81W to low pres 1008
mb near 09N86W to 12N104W to low pres 1009 mb near 12N111W to
14N125W to 12N135W to 14N140W. Scattered moderate and isolated
strong convection is present from 09N to 15N between 109W and
119W and from 09N to 14N between 130W and 138W.



A ridge will reside over the forecast waters west of Baja
California and produce mainly gentle to moderate NW to N winds
and seas in the 4-6 ft range the remainder of the week. A surface
trough will meander across the Baja California Peninsula and
Gulf of California through Mon night. A surface low will
periodically develop over the Gulf of California N of 30N.

Gulf of California...gentle southerly flow will persist across
the Gulf of California through the upcoming weekend, with the
exception of moderate to locally fresh winds surrounding the low
over the waters N of 30N.

Gulf of Tehuantepec: fresh to strong northerly winds are expected,
with the assistance of the drainage flow, during the overnight
and early morning hours tonight through Monday. Seas are
forecast to build to 6-8 ft with these winds. On Monday, winds
could increase to 30 kt and seas build 10 ft as tropical low
approaches from the Caribbean.


Gulf of Papagayo: fresh to strong offshore winds are expected
during the overnight and early morning hours through Friday
night, with moderate to fresh winds expected thereafter.

Gentle NE to E winds are expected N of the monsoon trough, while
moderate southerly winds are expected S of the monsoon trough
axis through Mon night with 3 to 6 ft seas throughout.


Low pressure is embedded in the monsoon trough near 12N111W.
Satellite-derived wind data indicate winds of 20 to 25 kt on the
east side of the low. Latest altimetry showed seas of 8 to 10 ft
on the N side of the low. Environmental conditions are expected
to be conducive for development of this system during the next
several days.

The subtropical ridge extends from 32N130W to near 25N118W.
Latest satellite-derived wind data show moderate to fresh
winds in the N semicircle of weak low pressure systems centered
near 17N121W and near 19N134W. Otherwise, light to moderate
anticyclonic flow is forecast N of the monsoon trough and W of

Long period southerly swell coming from the southern hemisphere
continue to subside. 7 to 8 ft seas are observed S of the Equator
between 95W and 120W. These seas will subside to less than 8 ft
by midday today. The next long period swell event is not expected
until the middle of next week.

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