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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 242120
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 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 1800 UTC surface analysis and satellite imagery through 
2115 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. So far in July, five named 
storms have developed in the basin. 

Hurricane Hilary is centered near 14.5N 104.9W at 24/2100 UTC, 
moving WNW at 7 kt. Estimated minimum central pressure is 986 
mb. Maximum sustained winds have increased to 75 kt with gusts 
to 90 kt. Numerous moderate scattered strong convection is 
within 120 nm of the center. Another cluster of similar 
convection is from 09N to 15N between 98W and 103W. 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 15.0N 117.8W at 24/2100 
UTC, moving W at 3 kt with a minimum central pressure of 997 mb.
Maximum sustained winds have increased to 55 kt with gusts to 65 
kt. Cluster of moderate to strong convection is within 120 nm in 
the N semicircle. Scattered moderate convection was noted 
elsewhere from 12N to 19N between 115W and 120W. 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 tonight or Tue. 
See the latest NHC forecast/advisory under AWIPS/WMO headers 
MIATCMEP5 WTPZ25 for more details.

Tropical Storm Greg is centered near 14.5N 134.3W AT 24/2100 
UTC, moving W at 10 kt. Estimated minimum central pressure is 
1003 mb. Maximum sustained winds remain 40 kt with gusts to 50 
kt. Scattered moderate isolated strong convection is within 90 
nm in the S and 60 nm in the N semicircles of the center. Greg 
is expected to remain a minimal tropical storm through the next 
36 hours or so, before weakening ensues. Greg could become a 
tropical depression by Wed, and a remnant low by Thu. See the 
latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP2 
WTPZ22 for more details.

...TROPICAL WAVES...

A tropical wave is just to the W of the Gulf of Tehuantepec 
along 96W north of 08N 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 09N83W to 09N90W to 12N97W. The ITCZ extends from 
11N136W to beyond 10N140W. Scattered moderate convection was 
from 05N to 10N east of 91W and within 90 nm if the trough axis 
between 91W and 96W.  

...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. 

$$
Cobb