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BID : 19624_KF5JRV
Read: GUEST
Subj: NWS NHC Eastern North Pacific WX 7/17
Path: IW8PGT<CX2SA<LU4ECL<PI8CDR<VE3TOK<VA3TOK<VE3UIL<N9PMO<NS2B<KF5JRV
Sent: 170717/1216Z 19624@KF5JRV.#NWAR.AR.USA.NA BPQK6.0.14
!RRR!000
AXPZ20 KNHC 170957
TWDEP
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
822 UTC Mon Jul 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
0900 UTC.
...SPECIAL FEATURES...
Hurricane Fernanda is centered near 13.4N 130.1W at 0900 UTC or
about 1260 nm WSW of the southern tip of Baja California, moving
WNW at 10 kt. Estimated minimum central pressure is 960 mb.
Maximum sustained winds are 105 kt with gusts to 130 kt. Numerous
strong convection is within 90 nm of the center. Elsewhere, scattered
moderate to isolated strong convection within 180 nm southeast
semicircle and 150 nm northwest semcircle. Fernanda is expected
to gradual weaken over the next several days. Large swells will
spread and expand out ahead of Fernanda to the NW and W during
the next few days, and are expected to reach the Hawaiian Islands
early Tuesday. See latest NHC forecast/advisory under AWIPS/WMO
headers MIATCMEP1/WTPZ21 for more details.
Showers and thunderstorms associated with an area of low pressure
near 14N105W, or about 300 nm south of Manzanillo, Mexico,
continue to show signs of organization. An earlier scatterometer
pass indicated fresh to strong winds within 90 nm in the
southeast quadrant of the center. Although upper- level winds are
not particularly favorable for development, the low pressure has
a high chance of development. Only a small increase in
organization of this system could lead to the formation of a
tropical depression during the next day or two while it moves
west- northwestward at 5 to 10 kt.
An area of low pressure centered near 13N116W, or about 740 nm
south- southwest of the southern tip of the Baja peninsula has
become better defined during the past day or so. Although
environmental conditions are only marginally conducive, this
system has a medium chance to become a tropical depression during
the next day or so before upper- level winds become unfavorable
for development as it moves slowly to the west or west-northwest
during the next few days.
...TROPICAL WAVES...
The axis of a tropical wave extends from the southwest Gulf of
Mexico southward across the isthmus of Tehuantepec and into the
adjacent Pacific waters to 08N95W, moving west at 10 to 15 kt.
Scattered moderate convection is noted from 09N to 12N between
95W and 98W.
A tropical wave reaches from 11N105W to low pressure near
14N105W 1008 mb to 10N105W, moving west at 10 to 15 kt.
Scattered moderate to isolated strong convection is noted from
10N to 15N between 100W and 105W. See above for more information
on the development of the low pressure.
A tropical wave reaches from 22N115W to low pressure near 13N115W
1009 mb, moving west at 10 to 15 kt. Scattered moderate to
isolated strong convection is noted from 09N to 14N between 115W
and 120W. See above for more information on the development of
the low pressure.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough axis extends from 10N85W to 08N95W to low
pressure near 14N105W to low pressure near 13N115W to 12N120W,
where it breaks to the east of Hurricane Fernanda, then resumes
from 11N133W to beyond 10N140W. Other than convection already
mentioned near Fernanda and the tropical waves, no signficant
convection is observed.
...DISCUSSION...
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
Please see the special features for information on the area of
low pressure SW of Acapulco, Mexico.
A surface trough from the coast of southern California southward
to off the coast of the Baja California peninsula will continue
to block the advance of the subtropical ridge into the region
and maintain generally gentle to moderate winds off the Baja
California peninsula through late week. Seas will still remain 5
to 7 ft however, in a mix of northerly and longer period S to SW
swell.
Farther south, moderate to fresh easterly winds will sweep
across the Revillagigedo Islands on the north side of low
pressure passing to the WSW of the region by mid week.
Gentle southerly flow will persist across the Gulf of California,
except for moderate southerly flow over the northern Gulf.
Light to gentle variable winds will prevail across the Gulf of
Tehuantepec through mid week before fresh northerly gap winds
pulse to strong at night. These winds will likely further
increase to fresh to strong by the end of the week into next
weekend.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
In the Gulf of Papagayo, moderate to fresh offshore winds will
pulse to fresh each night with nocturnal drainage through the
week, occasionally building seas close to 8 ft.
Gentle to moderate southerly winds are expected S of the monsoon
trough axis. Long period cross-equatorial southerly swell and 6
to 7 ft seas will continue to propagate into the waters reaching
the coast of Central America through the day. Another pulse of
large southerly swell will move into the waters by Tuesday.
REMAINDER OF THE AREA...
Please see the special features section for information on
Hurricane Fernanda.
Strong high pressure is centered N of the Hawaiian Islands along
39N and extends a ridge E to near 39N140W then SE to 25N125W.
This is producing moderate to fresh N to NE winds across NW
portions of the discussion area. The ridge will build midestly
eastward through mid week and tighten the pressure gradient to
the N of Fernanda as it moves W of 135W to produce fresh to
strong NE winds across much of the NW part of the area, where
seas will build to 8-9 ft.
Swells generated by Fernanda will propagate away from the center
across tropical waters W of 120W the next several days.
Northerly swell of 6 to 8 ft will propagate into the waters N of
25N and W of 120W, mixing with southerly swell generated from
Fernanda by Tuesday, with 7 to 9 ft combined seas. Elsewhere
outside of the region within 360 nm of the path of Fernanda,
winds will remain generally light to moderate with 5 to 7 ft
seas.
$$
Christensen
73 Scott KF5JRV
KF5JRV @ KF5JRV.#NWAR.AR.USA.NA
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