Eastern North Pacific Tropical Weather Discussion (Text)

AXPZ20 KNHC 260253

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Fri May 26 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 0000 UTC surface analysis and satellite imagery through
0215 UTC.


The southern portion of a western Caribbean Sea tropical wave 
has moved into the far eastern part of the area with axis 
extending along 82W north of 04N, moving west at 15 to 20 kt. 
Clusters of scattered moderate to strong convection are observed 
within 180 nm west of the wave. The wave is under upper level 
diffluent flow, which is helping to keep the convection active 
through at least Friday night as the wave continues westward 
across Central America and the far eastern waters.

The southern portion of a tropical wave extends into the area 


The Monsoon Trough axis extends from 10N85W to 11N95W to a 
1009 mb low near 13N101W to 10.5N106W to a 1010 mb low near 
10N111W to 08N120W to 09N130W. The intertropical convergence 
zone axis extends from 09N130W to 08N140W. Scattered moderate 
to isolated strong convection is within 180 nm south of 
axis between 89W and 92W, and within 60 nm north of the axis 
between 135W and 138W. Scattered moderate convection is within 
120 nm north of the axis between 115W and 119W.

In addition, scattered moderate convection is within 120 nm of 
the low in the southwest quadrant of the low.



A weak high pressure ridge protrudes east-southeastward across
these waters from well to the northwest of the area. The
associated gradient is supporting generally moderate northwest
winds across the Baja California Peninsula waters. Light to 
gentle northwest to north winds are noted elsewhere over the 
Mexican offshore waters to Acapulco. Seas are in the 4 to 5 ft 
range in mixed southwest and northwest swell across these 
waters, except across the Michoacan through Chiapas offshore 
waters where winds and seas are higher. This is due to 1009 mb 
low pressure located near 13N101W. Moderate to fresh south to 
southwest winds, with seas of 6 to 8 ft in southwest swell are 
present within 60 nm of the low in the southeast quadrant. Seas
in the range 4 to 6 ft are elsewhere across these offshore 
waters. The low is forecast to gradually dissipate through the 
next 18 hours or so, allowing for associated winds and seas to 
subside. The pressure gradient is forecast to tighten slightly to
the north of 20N through Friday as the ridge slightly builds 
into the region, with winds and seas increasing slightly across 
those areas. Gentle to moderate southeast winds occurring 
elsewhere between Tehuantepec and offshore of Acapulco will 
gradually weaken and veer southwest to west through Friday.

In the Gulf of California, mainly light to gentle variable winds 
are expected through the day except in the northern Gulf, with 
seas of 2 ft or less, except 3 to 5 ft near the entrance to the 
Gulf. Low pressure just to the north of the area over SW Arizona
will linger through the end of the week. A trough extending 
south to southwest from the low to Baja California Norte will 
linger as well. Fresh to near gale force southwest to west winds
have developed to the southeast side of the trough, and will 
persist through early Friday afternoon. The winds are enhanced 
through the gaps in the higher terrain of Baja. Seas are forecast
to build to 6 to 8 ft late tonight to the southeast of the 


Gentle southwest to west winds prevail between the Papagayo 
region and Tehuantepec, with seas of 4 to 6 ft in SW swell. 
Expect westerly monsoonal winds to spread across the coastal 
waters through Friday as a tropical wave moves across the area 
through Friday night. Nocturnal offshore winds will pulse to 
fresh levels near the Gulf of Papagayo by Saturday night, behind 
the wave, and again on Sunday night. Moderate southwest winds 
will continue to the south of 09N through Thursday night. A pulse
of southwest swell is forecast to propagate through the waters 
within 250 nm of Colombia and Ecuador through Saturday building 
seas to 7 ft. Otherwise, little change is forecast through the 
upcoming weekend.


A weak ridge extends from 28N140W southeastward through 22N130W
to 23N122W. The ridge is slowly shifting southeastward as a weak
trough from 32N122W to 26N131W, and a cold front just over the 
far northwest corner of the area are pushing southward. Moderate
northerly winds follow the trough and front in the northern 
waters, with long period north swell producing seas up to 8 ft
across the area from 29N to 32N between 126W and 132W expected
late tonight through early Friday afternoon. These seas subside
to less than 8 ft Friday evening. Elsewhere north of the deep 
tropics, the weak ridge will maintain moderate trade winds south 
of 18N, with seas of 5 to 7 ft expected through Friday. Slightly 
stronger high pressure to the northwest of the area will build 
southward by the end of the weekend and into early next week, 
supporting increasing trades to moderate to fresh levels and 
resultant seas of 5 to 8 ft across the waters north of the ITCZ.


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Page last modified: Friday, 26-May-2017 02:53:36 UTC