AXPZ20 KNHC 260333
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 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
Based on 0000 UTC surface analysis and satellite imagery through
Hurricane Hilary is centered near 16.0N 109.8W at 26/0300 UTC
moving WNW at 10 kt. Estimated minimum central pressure is 973
mb. Maximum sustained wind speed is 90 kt with gusts to 110 kt.
Numerous moderate to strong convection is seen within 90 nm in
the NE semicircle of the system. Numerous moderate isolated
strong convection is noted elsewhere within 75 nm SW semicircle.
A band of moderate convection is to the NW of the center from
16N to 19N between 109W and 111.5W. See latest NHC forecast/
advisory under AWIPS/WMO headers MIATCMEP4/WTPZ24 for more
Hurricane Irwin is centered near 16.1N 120.9W at 26/0300 UTC
moving W at 7 kt. Estimated minimum central pressure is 980 mb.
Maximum sustained wind speed is 80 kt with gusts to 100 kt.
Irwin is a small cyclone with numerous moderate to scattered
strong convection noted within 60 nm in the W and 30 nm in the E
semicircles. Irwin is expected to interact with hurricane Hilary
later this week. See latest NHC forecast/advisory under
AWIPS/WMO headers MIATCMEP5/WTPZ25 for more details.
Tropical Depression Greg is centered near 17.2N 138.8W at
26/0300 UTC moving NW at 12 kt. Estimated minimum central
pressure is 1006 mb. Maximum sustained winds are now 30 kt with
gusts to 40 kt. Additional weakening is expected during the next
couple of days, and Greg is forecast to degenerate into a
remnant low by Wednesday night. Convective activity associated
with Greg continues to decrease with scattered moderate isolated
strong convection noted within 60 nm in the W semicircle. See
latest NHC forecast/advisory under AWIPS/WMO headers
MIATCMEP2/WTPZ22 for more details.
A tropical wave is along 100W N of 05N moving W at 10-15 kt.
Convection is limited near the wave axis.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from 08N78W across western Panama and
southern Costa Rica to 09N84W to 09N90W to 08N96W to 13N105W.
Scattered moderate isolated strong convection is N of 07N E of
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
Gentle to moderate NW winds off the Baja California peninsula
are expected to continue through Wednesday, as high pressure
remains centered N-NW of the area. Seas will remain generally 4
to 6 ft in mixed swell through Wednesday. Thereafter, Hurricane
Hilary will begin impacting the forecast zones offshore of Baja
California through Friday with increasing winds and building
seas in mainly southerly swell. This could continue during the
upcoming 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 Thursday night into Friday morning. Hilary
is expected to impact the offshore waters beyond 200 nm off the
coasts of Michoacan, Colima and Jalisco through tonight, then
pass S of the Revillagigedo Islands early Wednesday, and south
of Clarion Island early Thursday. A couple of altimeter passes
provided observations of seas in the 7-9 ft range near the
coasts of of Michoacan, Colima and Jalisco. Seas of at least 8
ft associated with Hilary are forecast to reach the waters
between 107W and 115W in the vicinity of Cabo San Lucas
Wednesday into Thursday.
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 through the week,
occasionally building max 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 across the forecast
zones the next several days. Long period cross-equatorial SW
swell generating 5-7 ft seas will continue to propagate into the
forecast waters through Wednesday. Another set of cross-
equatorial long period SW swell of 6 to 9 ft will reach the
waters between Ecuador and the Galapagos Islands Thursday, and
continue through the upcoming weekend. Seas of 6-8 ft will reach
the offshore waters of Central America on Friday.
REMAINDER OF THE AREA...
High pressure is located N of the area with a ridge axis that
extends across the forecast waters north of 20N. The pressure
gradient between this system and the active zone of tropical
cyclones between 13N and 19N will maintain moderate to fresh
fresh N to NE winds W of 130W through Thursday. On this day,
cross equatorial SW swell of 8 to 9 ft will spread across the
waters south of 10N and east of 110W, persisting into the