NHC Tropical Weather Discussion (East Pacific)


07/26/2017 02:32 PM
NHC East Pacific Tropical Weather Discussion

000
AXPZ20 KNHC 262132
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Wed Jul 26 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 1800 UTC surface analysis and satellite imagery through
2100 UTC.

...SPECIAL FEATURES...

Hurricane Hilary is centered near 16.7N 113.2W at 26/2100 UTC or
about 415 nm SSW of the southern tip of Baja California moving W
at 11 kt. Estimated minimum central pressure is 972 mb. Maximum
sustained wind speed is 90 kt with gusts to 110 kt. Some slow
weakening is forecast during the next 48 hours. Numerous
moderate and scattered strong convection is within 90 nm of
center. Scattered moderate convection is elsewhere within 210 nm
of center. See latest NHC forecast/advisory under AWIPS/WMO
headers MIATCMEP4/WTPZ24 for more details.

Tropical Storm Irwin is centered near 15.1N 122.8W at 26/2100
UTC or about 865 nm WSW of the southern tip of Baja California
moving WSW at 6 kt. Estimated minimum central pressure is 996 mb.
Maximum sustained wind speed is 45 kt with gusts to 55 kt. Irwin
is forecast to move slowly with little change in strength during
the next 48 hours. Numrerous moderate and isolated strong
convection is from 15N to 18N between 122W and 125W. See latest
NHC forecast/advisory under AWIPS/WMO headers MIATCMEP5/WTPZ25
for more details.

...TROPICAL WAVES...

A tropical wave is along 102W/103W from 05N to 14N moving W at
10-15 kt. Isolated to scattered showers are near the wave axis.

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

The monsoon trough extends from to 09N84W to 08N95W to 09N102W
to 12N108W. Scattered moderate isolated strong convection is N
of 06N between 80W and 84W. Similar convection is from 07N to
09N between 90W and 93W, and from 08N to 10N between 90W and
95W. Scattered moderate convection is 08N to 11N between 104W
and 110W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
Gentle to moderate NW winds are expected to continue within 120
nm of the Baja California peninsula through Friday. Seas will
maintain 6 to 8 ft as southerly swell associated with Hurricane
Hilary will continue impacting the forecast zones offshore of
Baja California through Friday then remain W of the area during
the weekend. Gentle southerly flow will prevail in the Gulf of
California, and moderate southerly flow across the northern Gulf
of California.

Nocturnal fresh northerly winds are forecast across the Gulf of
Tehuantepec through Friday morning with seas peaking at 8 ft
briefly during the period of strongest winds. Hilary is
currently south and midway between Revillagigedo Islands and
Clarion Island. Fresh to strong winds and seas of at least 12-
13 ft are reaching those islands.

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
Across the Gulf of Papagayo, expect fresh winds each night with
the assistance of the nocturnal drainage flow the next few days,
occasionally building maximum seas to 7 ft in a mix of E wind
waves and long period SW swell.

Gentle to moderate S to SW winds are expected the next few days.
Long period cross-equatorial SW swell will continue to propagate
into the forecast waters through Saturday, reaching the waters
between Ecuador and the Galapagos Islands on Thursday with
building seas of 8-9 ft.

REMAINDER OF THE AREA...
High pressure is located N of the area with a ridge axis
extending across the forecast waters N of 22N. The pressure
gradient between this system and the active zone of tropical
cyclone activity will maintain moderate to fresh N to NE winds W
of 120W through Saturday. An altimeter pass indicated seas up to
9 ft associated with post-tropical cyclone Greg across the west-
central waters from 17N to 21N W of 138W. At 26/2100 UTC...The
Central Pacific Hurricane Center issued the last advisory on
Greg. Long period cross equatorial 8-9 ft SW swell will spread
across the waters S of 10N and E of 110W, persisting into the
weekend.

$$
GR