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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 270937
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Thu Jul 27 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 Hilary is centered near 17.3N 115.1W at 0900 UTC, 
moving WNW at 10 kt. Estimated minimum central pressure is 981 
mb. Maximum sustained winds are 75 kt with gusts to 90 kt. 
Slight weakening is expected during the next 48 hours. Numerous 
moderate to strong convection is within 75 nm N and 45 nm S 
semicircles of the center. A band of scattered moderate isolated 
strong convection is from 15N to 18N between 111W and 113W. See 
latest NHC forecast/advisory under AWIPS/WMO headers 
MIATCMEP4/WTPZ24 for more details.

Tropical Storm Irwin is centered near 14.7N 123.8W at 0900 UTC, 
moving WSW at 5 kt. Estimated minimum central pressure is 997 mb.
Maximum sustained winds are 50 kt with gusts to 60 kt. Irwin is 
forecast to move slowly over the open Pacific with little change 
in strength during the next 48 hours. Irwin remains a sheared 
tropical cyclone with numerous moderate scattered strong 
convection within 120 nm NW of the center. See latest NHC 
forecast/advisory under AWIPS/WMO headers MIATCMEP5/WTPZ25 for 
more details.

...TROPICAL WAVES... 

A tropical wave is along 106W from 05N to 14N moving W at 10-15 
kt. Scattered moderate convection is within about 90 nm on 
either side of the wave axis. 

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

The monsoon trough extends from 08N78W to 08N98W to 11N110W. The 
ITCZ axis extends from 10N127W to 07N140W. Scattered moderate 
isolated strong convection is north of 07N between 82W and 95W. 
Scattered moderate convection is from 08N to 12N between 108W 
and 114W.

...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 
remain 6 to 8 ft as southerly swell associated with Hurricane 
Hilary will continue impacting the forecast zones offshore of 
Baja California through Friday then shift W of the area this 
weekend.

Nocturnal fresh northerly winds are forecast across the Gulf of 
Tehuantepec through Friday morning with seas peaking around 7 ft 
during each period of strongest winds. Hilary will pass south of 
Clarion Island overnight, in extreme SW waters of marine zone 
PMZ015. Marine conditions will steadily improve SW of Baja 
California through Fri.

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. Long period cross equatorial SW swell 
of 8-9 ft will spread across the waters S of 10N and E of 110W, 
persisting into the weekend. 

$$
Mundell