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KF5JRV > WX 07.10.17 13:25l 101 Lines 4525 Bytes #999 (0) @ NA
BID : 5414_KF5JRV
Read: GUEST
Subj: NWS NHC Eastern N Pacific WX 10/7
Path: IW8PGT<CX2SA<XE1FH<N9PMO<NS2B<KF5JRV
Sent: 171007/1120Z 5414@KF5JRV.#NWAR.AR.USA.NA BPQK6.0.14
000
AXPZ20 KNHC 070959
TWDEP
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Sat Oct 7 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.
..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from 10N74.5W TO 08.5N79W TO 16N97W
TO 18N107W TO low pres 1007 MB near 11.5N110.5W TO 10N121 TO low
pres 1010 MB near 12N136.5W TO 11.5N140W. Scattered moderate
isolated strong convection is noted near the trough within 90 nm
of the Mexican coast from 96W to 101.5W.
...DISCUSSION...
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
The broad cyclonic circulation constituting a Central American
Gyre that has affected the region for the past few days has
begun to shift northward across the southern Gulf of Mexico, but
is still producing an atypical NW to N gap wind event over the
Gulf of Tehuantepec. Overnight ASCAT data showed these northerly
gaps winds diminishing to around 15 kt, and are expected to
weaken further through around noon today, before winds become
light from the south during the afternoon. Elsewhere between
Tehuantepec and Cabo Corrientes, light to gently W to SW winds
prevail, as the effects of the gyre gradually diminish. Seas
across this region are generally 7-9 ft in a mix of cross
equatorial swell and SW wind wave generated from the recent
large swath of westerly monsoonal winds. Little change in winds
is expected here over the weekend, while seas subside modestly
to 6-7 ft.
The pressure gradient between a low pressure trough along the
Sierra Madre Occidentales of Mexico and high pressure ridging
from the NE Pacific to just offshore of Baja California Sur will
generally support gentle to moderate N to NW winds along the
Pacific coast of Baja through tonight. Seas during this time
will range from 5 to 7 feet. Winds will weaken slightly on
Sunday as a trough of low pressure develop N to S along the
length of the Baja Peninsula. A fresh round of NW swell will
build seas to above 8 ft N of 26N on Sunday morning and N of 21N
by Tuesday evening. Seas could peak near 12 ft near 30N124W on
Monday evening.
Moderate northwesterly winds across N through central portions
of the Gulf of California overnight are building seas 4 to 6 ft,
with little change expected through this afternoon before winds
and seas diminish tonight. As the trough develops across Baja
California Sunday, southerly winds will develop inside the Gulf
of California and freshen throughout the day. Global models
suggest that strong northerly winds could spread across N
portions of the Gulf on Monday evening or night in response to
building high pressure over the great Basin of the United States.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
Convection over the offshore zones from El Salvador to Guatemala
has diminished significantly during the past 24 hours as the
Central American Gyre continues lifting northward across the
Yucatan Peninsula and the Gulf of Mexico. Strong SW to W
monsoonal winds induced by the gyre from Guatemala to Nicaragua
have diminished overnight, and are generally 10-20 kt. Seas
remain high, however, and are 8-13 ft in mixed SW cross
equatorial swell and SW wind swell, with highest seas offshore
of Nicaragua. This mix of swell will continue to generate large
and dangerous surf along the area coasts and reefs throughout
the weekend as seas gradually subside.
As the monsoonal flow continues to abate, associated tropical
moisture and rainfall over Central America will continue to
taper off. Runoff from the excessive heavy rains of recent day
could still produce flash flooding and mudslides.
REMAINDER OF THE AREA...
Gentle to moderate winds prevail to the north of the monsoon
trough to 20N, and to the west of 125W. A weakening stationary
front is just W of the far NW corner of the discussion area,
where winds N of 28N and W of 139W are SE at 20-25 kt, and seas
8-10 ft. Seas in this area will subside today as the front
drifts W and away from the area. Long period SW swell is
maintaining sea of 8 to 10 feet in the discussion area generally
from 06N to 16N east of 117W. Seas in this area will subside to
less than 8 ft by late Sunday.
$$
Stripling
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