Eastern North Pacific Tropical Weather Discussion (Text)

AXPZ20 KNHC 250241

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Thu May 25 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 Monsoon Trough axis extends from 09N79W to a 1008 mb low at 
14N94W to 13N104W to another 1008 mb low at 09N109W to 09N124W. 
ITCZ axis extends from 09N124W to 08N134W to 07N140W. Scattered 
moderate to numerous strong convection is within 180 nm south of 
the axis between 94W and 105W. Scattered moderate to isolated 
strong convection is within 120 nm of the axis between 125W and 
128W, and also within 60 nm of the axis between 121W and 125W. 
Scattered moderate convection is within 60 nm of the axis between
113W and 115W.



Rather weak high pressure is present over the area, with the 
associated gradient supporting generally moderate northwest
winds prevailing across the Baja California Peninsula waters.
Light to gentle NW to N winds are noted elsewhere over the 
Mexican offshore waters. Seas are in the 4 to 5 ft range in mixed
SW and NW swell across these waters, with slightly higher seas 
of 5 to 6 ft south of Puerto Angel. The pressure gradient will 
tighten slightly to the north of 20N through Friday as the ridge 
builds some into the region, with winds and seas increasing 

In the Gulf of California, mainly light to gentle variable winds 
are expected through Thursday 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 is presently deepening quite rapidly just to 
the north of the area over SW Arizona, and should remain pretty 
low through at least Thursday night. A trough will extend from 
the low across the northern Gulf to Baja California Norte through
Friday. Fresh to strong southwest to west are expected to 
develop shortly to the southeast of the trough tonight, and then 
again on Thursday night into Friday as winds become enhanced 
through the gaps in the higher terrain of Baja. Seas are expected
to build to around or to 8 ft each night during the nocturnal 
wind max.

S of 16N including the Gulf of Tehuantepec, broad and ill-defined 
low pressure has persisted across the offshore waters SW of 
Tehuantepec the past few days, and continues to gradually 
drift westward. Last visible satellite imagery showed the 
presence of another weak low pressure to the south-southeast of 
the Gulf of Tehuantepec near 14N94W. The low is on the northeast 
edge of the large clusters of very deep convection described 
above under ITCZ/Monsoon Trough. This low is expected to remain 
about stationary through the next 24 hours, and perhaps dissipate
thereafter. Another weak low is noted to the west of this deep 
convection near 09N109W moving westward. Models depict this low 
to track more in a northwesterly direction beginning late on 
Thursday and through Friday while beginning to slow down as 
ridging to its NW builds to the SE. Gentle to moderate SE winds 
occurring between Tehuantepec and offshore of Acapulco will 
gradually weaken and veer SW to W through Friday.


Gentle to moderate E to SE winds prevail between the Papagayo 
region and Tehuantepec, with seas of 4 to 5 ft in SW swell. 
Expect these conditions to continue through this evening before 
gentle to moderate SW to W monsoonal winds spread N of 09N and 
into the coastal waters through Friday. Nocturnal offshore winds
will pulse to fresh levels near the Gulf of Papagayo by Saturday
night, and again on Sunday night. Moderate SW winds will continue
to the south of 09N through Thursday night. A new pulse of SW 
swell is progged to arrive Thursday through late Friday. 
Otherwise, little change is anticipated through the upcoming 


A weak ridge extends from 32N140W southeastward to near 17N113W.
The ridge will change little through Thursday as a weak cold 
front moves across the northeast portion of the area, then build 
some southeastward Friday through Saturday once the front the 
exits the area. A set of long period NW swell producing max seas
of 8 to 9 ft is forecast to approach the area from 31N to 32N 
between 125W and 135W on Thursday, before subsiding to less than 
8 ft late Friday afternoon. Elsewhere N of the deep tropics, the 
weak ridge will maintain moderate trade winds S of 18N, with seas
of 5 to 7 ft expected through Friday.


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Page last modified: Thursday, 25-May-2017 02:41:46 UTC