AXPZ20 KNHC 281515
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1510 UTC Fri Jul 28 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 1200 UTC surface analysis and satellite imagery through
Tropical Storm Hilary is centered near 19.2N 118.4W at 28/1500
UTC or about 525 nm WSW of the southern tip of Baja California
moving NW at 7 kt. Estimated minimum central pressure is 996 mb.
Maximum sustained wind speed is 55 kt with gusts to 65 kt.
Scattered moderate convection is from 16N to 21N between 115W
and 120W. See latest NHC forecast/advisory under AWIPS/WMO
headers MIATCMEP4/WTPZ24 for more details.
Tropical Storm Irwin is centered near 14.8N 125.3W at 28/1500
UTC or about 1000 nm WSW of the southern tip of Baja California
and is stationary. Estimated minimum central pressure is 998 mb.
Maximum sustained wind speed is 50 kt with gusts to 60 kt.
Scattered to numerous moderate and isolated strong convection is
from 13N to 17N between 121W and 128W. See latest NHC forecast/
advisory under AWIPS/WMO headers MIATCMEP5/WTPZ25 for more
A tropical wave extends from 07N97W to 15N96W moving W at 10 to
15 kt. Scattered moderate convection is from 10N to 16N between
93W and 98W.
A tropical wave extends from 06N112W to 16N112W moving W at 5 to
10 kt. Scattered moderate convection is from 07N to 15N between
108W and 116W.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from 10N85W to 08N101W to 10N111W then
resumes near 12N130W to 09N137W. The ITCZ extends from 09N137W
to 09N140W. Scattered to numerous moderate and isolated strong
convection is from 04N to 09N E of 85W and from 06N to 11N
between 93W and 107W. Scattered moderate convection is from 07N
to 11N W of 128W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
High pressure centered NW of the area will support gentle to
moderate NW winds within 120 nm of the Baja California peninsula
through Sunday. Seas of 6 to 8 ft associated with tropical
cyclone Hilary will continue to impact the offshore zones of Baja
California through the upcoming weekend. As Hilary moves away
from this area, a ridge axis will fill in between the departing
cyclone and Baja California, resulting in moderate to fresh NW
winds developing Sunday through early next week. Likewise, seas
will build into a range of 7 to 9 ft due to another round of
long-period southerly swell.
Nocturnal fresh northerly winds are forecast across the Gulf of
Tehuantepec through this morning with seas peaking around 8 ft.
Cross equatorial long period southerly swell with seas of 7 to 8
ft will reach the offshore waters between the Gulf of
Tehuantepec and Cabo Corrientes on Sunday, and the waters
between Los Cabos and Cabo Corrientes on Monday. Elsewhere,
generally moderate NW winds and seas of 5 to 7 ft will prevail.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA,
COLOMBIA, AND WITHIN 750 NM OF ECUADOR...
Across the Gulf of Papagayo, expect fresh winds to develop
tonight and again Saturday night with the assistance of the
nocturnal drainage flow, building maximum seas of 6 to 7 ft in a
mix of E wind waves and long period SW swell.
Otherwise, gentle to moderate S to SW winds are expected the
next few days. Strong long period cross-equatorial S-SW swell
will continue to propagate into the forecast waters through
Saturday, with seas 8 to 9 ft reaching as far north as 10N by
tonight. The area of 8 ft seas will then reach just offshore all
Central America Pacific coastal sections by Sunday.
REMAINDER OF THE AREA...
High pressure is located N of the area with a ridge axis
extending across the northern forecast waters N of 25N. The
pressure gradient between this system and the active zone of
tropical cyclones will maintain moderate to fresh N to NE winds W
of 120W through Saturday. Long period cross equatorial SW swell
of 8 to 9 ft will spread across the waters S of 10N and E of
110W, persisting through Sunday night. As the tropical cyclone
activity shifts to the NW over the discussion waters later this
weekend, a weak pressure pattern will develop between the
cyclones and the equatorial trough to the south. This will result
in a broadening area of gentle to moderate winds between 10N and
20N, W of 115W early next week.