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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 241524
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1326 UTC Mon Jul 24 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 1200 UTC surface analysis and satellite imagery through
1500 UTC.

...SPECIAL FEATURES... 

The Eastern Pacific region remains very active with three tropical
cyclones: from east to west, Hurricane Hilary, Tropical Storm 
Irwin and Tropical Storm Greg. Hilary is forecast to become a
major hurricane on Tuesday, while Irwin is expected to reach 
hurricane intensity. So far in July, five named storms have 
developed.

Hurricane Hilary is centered near 14.1N 104.2W at 24/1500 UTC, 
moving WNW at 7 kt. Estimated minimum central pressure is 989 
mb. Maximum sustained winds have increased to 70 kt with gusts 
to 85 kt. Numerous moderate scattered strong convection is 
within 90 nm of the center. Another cluster of similar convection
is from 16N to 18N between 103W and 105W. Continued strengthening 
is forecast during the next 48 hours, and Hilary is likely to 
become a major hurricane on Tuesday as it continues on a WNW 
track about 200 to 250 nm west of the Mexican coast for the next 
couple of days. See the latest NHC forecast/advisory under 
AWIPS/WMO headers MIATCMEP4 WTPZ24 for more details.

Tropical Storm Irwin is centered near 14.8N 117.4W at 24/1500
UTC, moving W at 3 kt with a minimum central pressure of 999 mb.
Maximum sustained winds have increased to 50 kt with gusts to 60
kt. Cluster of moderate to strong convection within 60 nm north
semicircle. Scattered moderate isolated strong convection is 
elsewhere from 11N to 16N between 114W and 119W. Irwin will 
remain in relatively close proximity to Hilary the next few days.
Gradual strengthening is expected during the next 48 hours, and 
Irwin is forecast to become a minimal hurricane in about 24 
hours. See the latest NHC forecast/advisory under AWIPS/WMO 
headers MIATCMEP5 WTPZ25 for more details.

Tropical Storm Greg is centered near 14.6N 133.2W AT 24/1500 UTC,
moving W at 10 kt. Estimated minimum central pressure is 1003 
mb. Maximum sustained winds are 40 kt with gusts to 50 kt. 
Scattered moderate to isolated strong convection is within 120 
nm SW semicircle of the center. Weakening is forecast during the 
next 48 hours, and Greg is expected to become a tropical 
depression by early Wednesday, and a remnant low by Thursday. 
See the latest NHC forecast/advisory under AWIPS/WMO headers 
MIATCMEP2 WTPZ22 for more details.

...TROPICAL WAVES...

A tropical wave is along the Gulf of Tehuantepec north of 06N 
moving west at 10 to 15 kt. Isolated moderate convection is from
06N to 13N between 90W and 94W.

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

The monsoon trough is analyzed E of the tropical cyclone activity
from 09N84W to 12N100W. The ITCZ extends from 11N136W to beyond 
09N140W. A cluster of moderate to strong convection is from 10N
to 12N between 97W and 100.5W. Scattered moderate convection is 
within 150 nm s of monsoon trough E of 90W. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Gentle to moderate NW winds off the Baja California peninsula 
are expected to continue through mid-week, as high pressure 
remains centered N of the area. Seas will remain 4 to 7 ft in a 
mix of long period north and southwesterly swell. Gentle 
southerly flow will generally prevail in the Gulf of California, 
except for moderate southerly flow over the northern Gulf. 

Nocturnal fresh northerly winds are forecast over the Gulf of 
Tehuantepec Tuesday through Thursday nights. Hilary is expected 
to impact the offshore waters beyond 200 nm off the coasts of 
Guerrero, Michoacan, Colima and Jalisco through Tue, then pass 
south of the Revillagigedo Islands Wed as a major hurricane.
Seas of at least 8 ft, associated with Hilary are forecast to 
reach the waters between Los Cabos and Cabo Corrientes on 
Wednesday.

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 near 8 ft in a mix of east wind
waves and long period southwest swell.

Gentle to moderate S to SW winds are expected across the forecast
zones. Long period cross-equatorial SW swell creating 5-7 ft 
seas will continue to propagate into the forecast waters through
mid week. Another set of cross-equatorial long period SW swell of
6 to 9 ft will reach the waters between Ecuador and the Galapagos
Islands late Wednesday, and the coast of Central America on 
Thursday. 

REMAINDER OF THE AREA... 

High pressure is located north of area with a ridge axis that 
extends across the forecast waters north of 20N. The pressure 
gradient between this system and an active zone of tropical 
cyclones between 12N and 20N will maintain fresh N to NE winds W 
of 125W through mid-week. Seas associated with T.S. Greg are 
already propagating across the waters N of 20N W of 130W. By 
Thursday night, cross equatorial southwesterly swell of 8 to 9 
ft will spread over the waters south of 10N and east of 110W, 
persisting into next weekend. 

$$
GR