000
AXPZ20 KNHC 292159
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2159 UTC Sat Jul 29 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... 
Tropical Storm Hilary is centered near 22.3N 122.5W at 29/2100 
UTC or about 660 nm W of the southern tip of Baja California 
moving NW at 11 kt. Estimated minimum central pressure is 998 
mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt.
Scattered moderate to isolated strong convection within 60 nm of
the center. See latest NHC forecast/advisory under AWIPS/WMO 
headers MIATCMEP4/WTPZ24 for more details.

Tropical Storm Irwin is centered near 15.6N 124.9W at 29/1500 
UTC or about 960 nm WSW of the southern tip of Baja California 
moving N at 2 kt. Estimated minimum central pressure is 998 mb. 
Maximum sustained wind speed is 50 kt with gusts to 60 kt. 
Scattered moderate convection is from 11N to 16N between 123W and
127W. See latest NHC forecast/advisory under AWIPS/WMO headers 
MIATCMEP5/WTPZ25 for more details.

...TROPICAL WAVES...
A tropical wave extends from 06N87W TO 22N89W moving W at 10 to 
15 kt. Scattered moderate convection is from 06N to 11N between 
82W and 93W. 

A tropical wave extends from 06N103W to 17N102W moving W at 10 
to 15 kt. Scattered moderate and isolated strong convection is 
from 11N to 15N between 101W and 107W. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
The monsoon trough extends from 10N79W to 10N90W to 13N103W to 
10N110W to 13N119W, then continues from 12N129W to 10N140W. No
intertropical convergence zone is analyzed E of 140W. No 
significant convection is observed.

...DISCUSSION...

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. Tropical Cyclone Hilary's affects are mainly 
west of the area, with some small southerly swell to fade across 
the outer waters beyond 150 nm through tonight. The NW movement 
of the system will allow a ridge axis to fill in between the 
departing cyclone and Baja California, which will result in 
moderate to fresh NW winds Sunday through Monday night. As these 
winds increase, seas will build into a range of 7 to 9 ft as the 
wind waves combine with a round of long-period southerly swell 
moving into the region during the next few days.

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 late Sunday night into
early 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 moderate to occasional fresh
winds to develop tonight 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. By Monday...global models
are suggesting a weak area of low pressure to develop in the
vicinity of 10N90W and move generally westward through Tuesday
and then more W-NW through Wednesday. Likely S-SW monsoonal flow
will build seas to 7 to 9 ft across the waters S of Guatemala and
the Gulf of Tehuantepec coastline.

Elsewhere, gentle to moderate S to SW winds are expected the 
next few days. Large long period cross-equatorial S-SW swell 
will continue to propagate into the forecast waters during the 
weekend, with seas 8 to 9 ft reaching as far north as 10N. The 
area of 8 ft seas will then reach just offshore all Central 
America Pacific coastal sections by Sunday. Seas will gradually 
subside starting Monday. 

REMAINDER OF THE AREA...
A 1027 mb high is located N of the area near 37N136W with a 
ridge axis extending to Baja California Norte. The pressure 
gradient between the high pressure system and the active zone of 
tropical cyclones will maintain moderate to fresh N to NE winds W
of 120W through Sunday. Long period cross equatorial SW swell of
8 to 9 ft is spreading across the waters S of 10N and E of 110W,
and will persist through Sunday night. As the tropical cyclone 
activity shifts to the NW and eventually weakens across the 
northwestern discussion waters, 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 110W early next week. 

$$
Christensen