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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 180234
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Fri Oct 18 2019

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
0130 UTC.

...SPECIAL FEATURES...

Tropical Storm Octave is centered near 9.8N 127.1W at 18/0300 
UTC moving W at 3 kt. Estimated minimum central pressure is 1006 
mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. 
Numerous moderate and isolated strong convection is noted within
210 nm in the SE semicircle and 120 nm in the NW semicircle of 
Octave. Octave is forecast to maintain strength through Fri 
before weakening back to a tropical depression this weekend. 
Octave is also forecast to not move much through the next few 
days. See latest NHC forecast/advisory under AWIPS/WMO headers 
MIATCMEP3/WTPZ23 KNHC for more details.

Heavy Rainfall Event for southern Mexico: Moderate to fresh 
strong southwesterly monsoonal flow under a very moist and 
unstable atmosphere will gradually weaken through the remainder
of tonight, and the heavy rainfall threat should begin to
diminish somewhat. Until then, heavy rainfall remains possible 
over portions of southern Mexico from Chiapas to Jalisco. These 
rains could cause flooding and mudslides, especially in 
mountainous areas. Strong gusty winds are possible in and near 
showers and thunderstorms. Please monitor products from your 
local or national meteorological service for more details on this
event.

...TROPICAL WAVES...

The axis of a tropical wave is near 82W, from near the 
Colombia/Ecuador border to eastern Panama, moving W at 10-15 kt.
Scattered moderate convection is noted mainly over western Panama
and SE Costa Rica from 07N to 09N between 80W and 84W.

The axis of a tropical wave is near 121W from 03N to 15N, moving
W at 5-10 kt. No significant convection is noted.

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

The monsoon trough axis extends from near the Costa
Rica/Nicaragua border near 11N86W to across the Gulf of
Tehuantepec to 16N98W to low pressure near 14N113W to 10N123W
then resumes from 10N131W to 11N140W. Scattered moderate and 
isolated strong convection is noted from 10N to 15N between 93W
and 97W, within 180 nm either side of the monsoon trough between
98W and 108W, and from 05N to 10N between 130W and 136W.

OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 

Please read the Special Features section for more details about 
a heavy rainfall event over southern Mexico.

An area of low pressure that was previously analyzed about 75 nm
S of Cabo Corrientes has opened up into a surface trough from
21N104W to 16N106W, with scattered moderate and isolated strong 
convection noted within 120 nm NW of the trough axis. This trough
is expected to dissipate by the weekend.

Moderate to fresh SW monsoonal flow and wave heights of 6-8 ft 
will remain to the S of the monsoon trough in the Gulf of 
Tehuantepec zone and vicinity through Sat.

A ridge will build across the Baja California offshore waters in
the wake of a dissipating cold front. A tight pressure gradient
between this ridge and deep troughing which will develop over
interior California will support gale force winds offshore of
Cape Conception. Outer fresh to strong winds will manage to
filter southward into the offshore zones of Baja California
Norte later tonight through the weekend. Along with these winds,
a set of large NW swell will propagate into the Baja California 
waters, with seas reaching a range of 10-14 ft by Sat. This 
swell will spread SE reaching the Revillagigedo Islands by Sat 
night and continuing through Sun night. The swell will then 
gradually decay early next week.

Gulf of California: The pressure gradient will tighten across the
region early next week as high pressure W of the area shifts 
NE. This will allow for NW flow to freshen in the northern and 
central Gulf.

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

Gentle to moderate SW to W winds will change little through Fri.
SW winds will become moderate to fresh S of the monsoon trough 
this weekend before diminishing somewhat early next week. These 
winds will help to build seas slightly for the weekend.

REMAINDER OF THE AREA...

Please read the Special Features section for more details about 
Tropical Storm Octave

A 1010 mb area of low pressure is embedded in the monsoon trough
near 14N113W. Scattered moderate and isolated strong convection
is within 210 nm in the W quadrant of the low. This low is
currently forecast to drift NE, eventually opening up into a
trough this weekend.

A large set of NW swell is propagating into the northern waters 
with seas currently 8-12 ft. This swell will continue to 
propagate SE, and seas will peak around 10-14 ft N of 24N 
between 118W and 128W Fri night into Sat, aided by fresh to 
strong winds which will spread southward from off the southern 
California coast. The edge of seas of 8 ft or greater will reach 
to 10N and W of 110W by Sat night into Sun. This swell will 
gradually decay early next week along with the fresh to strong 
winds which will diminish.

Otherwise, a weak ridge extends across the waters S of the 
dissipating cold front and N of the monsoon trough. Mainly
moderate to fresh trades are noted underneath the ridge as
supported by recent scatterometer data, except for a small area
of fresh to strong winds near 140W in the wake of a now departed
surface trough. These conditions near 140W will shift westward
tonight as the trough continues away from the area.

$$
Lewitsky