Tropical Weather Discussion
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000
AXPZ20 KNHC 210901
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0901 UTC Sat Oct 21 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
0900 UTC.

...TROPICAL WAVES...

The axis of a tropical wave is near 86W north of 05N, moving W
at 10 to 15 kt. Scattered moderate and isolated strong convection
is noted from 10N to 12N between 85W and 87W.

The axis of a tropical wave is near 96W N of 06N, moving W at 10
to 15 kt. Scattered moderate and isolated strong convection is
from 12N to 15N between 95W and 99W.

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

The monsoon trough extends from 10N85W to 08.5N94W to 08.5N110W.
The ITCZ then continues from 08.5N110W to 09N140W. Scattered
moderate to strong was noted from 11N to 14N between 90W and 93W.
Scattered moderate isolated strong convection is noted from 06N
to 10N between 90W and 102W. Scattered moderate isolated strong
convection is noted from 06N to 09N between 112W and 118W.
Scattered moderate isolated strong convection was noted from 08N
to 10N between 134W and 136W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

High pressure over the Gulf of Mexico has weakened enough to
loosen the pressure gradient over the Gulf of Tehuantepec and
diminish winds to 20 kt or less as depicted by the most recent
ASCAT pass. A cold front will enter the Gulf of Mexico on Sunday
evening. This front will bring strong to near gale force winds
to the Gulf of Tehuantepec Sun night, increasing to gale force
Mon night. Winds will further increase, possibly reaching minimal
storm force the middle of next week.

The pressure gradient between high pressure centered near 33N131W
and a surface trough over the Gulf of California has strengthened
winds west of Baja California Norte. Winds over this area are
expected to diminish to 20 kt or less by this afternoon. Long
period NW swell prevails over the waters off Baja California
Norte. Seas will peak near 15 ft off the northernmost coast of
Baja California Norte today before starting to subside. The swell
will propagate SE, with seas 8 ft or greater covering all of the
offshore forecast zones W of Baja California through the weekend
before subsiding below 8 ft the middle of next week.

High pressure building over the Great Basin region of the
western United States will cause NW winds to strengthen over the
Gulf of California through Tuesday, diminishing thereafter as the
gradient weakens. Winds will be strongest on Sunday night
through Monday when seas peak around 8 ft.

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

Gentle to moderate winds will prevail over the forecast area the
next several days. NW swell originating from the Gulf of
Tehuantepec will propagate into the offshore waters of Guatemala
and El Salvador by the middle of next week.

REMAINDER OF THE AREA...

A set of large NW swell with seas near 15 ft will continue to
propagate SE while gradually subsiding into early next week. Seas
will subside to less than 12 ft Sunday afternoon. Seas
associated to this swell are expected to further subside, to
less than 8 ft, by midweek.

$$
AL


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