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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 270311
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
310 UTC Tue Sep 27 2016

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 0000 UTC surface analysis and satellite imagery
through 0300 UTC.

...SPECIAL FEATURES...

Tropical Storm Roslyn is centered near 17.2N 118.4W at 27/0300Z,
or about 600 nm southwest of the southern tip of the Baja
California peninsula, moving northeast or 60 degrees at 4 kt.
Estimated minimum central pressure is 1000 mb. Maximum sustained
wind speed is 45 kt with gusts to 55 kt. Numerous moderate to
isolated strong convection is noted within 210 nm in the
northeast quadrant of the storm. Roslyn is expected to begin to
weaken tonight, becoming a depression Tuesday night, and is
expected to remain west of the offshore forecast zones off Baja
California. Please refer to the latest NHC forecast/advisory under
AWIPS/WMO headers WTPZ23 KNHC/TCMEP3, or visit the NHC website at
http://hurricanes.gov for additional details.

Tropical Depression Nineteen-E is centered 12N140W at 27/0300Z,
or about 980 nm east-southeast of HILO Hawaii, moving north or
350 degrees at 4 kt. Estimated minimum central pressure is 1005
mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt.
Scattered moderate convection is within about 180 nm in the
southeast semicircle of the center. T.D.Nineteen-E is forecast
to gradual strengthen during the next couple of days as it drifts
northward. Please refer to the latest NHC forecast/advisory under
AWIPS/WMO headers WTPZ24KNHC/TCMEP4, or visit the NHC website at
http://hurricanes.gov for additional details.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough extends from 08N78W to 10N95W to 09N115W,
resuming near 12N120W and extending 12N140W. Scattered moderate
convection is noted within 210 nm either side of the monsoon
trough axis between 85W and 100W. Scattered moderate convection
also noted within 120 nm either side of the monsoon trough
axis west of 125W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Southerly swell of 5 to 7 ft will expand across the waters off
Baja California Sur on the eastern periphery of T.S. Roslyn
through late Wednesday. The main area of winds and seas will
remain beyond 250 nm, but squalls are possible across Clarion
Island and adjacent waters to the west tonight and early Tuesday.
Building high pressure over the Great Basin to the north of the
region will allow a brief surge of fresh northerly winds across
the northern Gulf of California through late Tuesday morning.

A cold front is forecast to move across the Gulf of Mexico
waters tonight followed by a stronger cold front on Thursday.
High pressure behind the fronts will likely induce the first Gulf
of Tehuantepec gap wind event of the season by Wednesday night
into Thursday morning. Marine guidance suggests Northerly winds of
20-30 kt with seas up to 9-10 ft by Thursday.

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...

Mainly light and variable winds are noted north of the monsoon
trough while gentle to locally moderate south to southwest flow
is expected south of monsoon trough the middle of the week. Combined
seas of 3-6 ft, primarily in long-period southwest swell, are
expected through the middle of the week.

REMAINDER OF THE AREA... 

A cold front moving southeast out of the north central Pacific
will weaken the subtropical ridge to the north of the region for
the next couple of days. This will maintain gentle to moderate
northeast winds across most of the region outside of areas of
tropical cyclone activity and north of the monsoon trough with 5
to 6 ft seas. moderate to occasionally fresh southerly flow will
dominate south of the monsoon trough with 6 to 7 ft seas. 

$$
CHRISTENSEN