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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 272200
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Thu Apr 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 1800 UTC surface analysis and satellite imagery through
2145 UTC.

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

A surface trough axis extends from 09N85W TO 06N94W TO 07N103W, 
where scatterometer winds indicate that the ITCZ forms, and then 
continues WSW through 05N115W TO 05N126W TO 05N134W TO beyond
05N140W. Scattered moderate to strong convection is noted within
60 nm of axis between 108W and 110.5W and also between 111W and 
113W. Scattered moderate/isolated strong convection is within 
60 nm south of axis between 100W and 106W. Scattered moderate 
convection is within 150 nm north of axis between 115W and 118W,
between 125W and 129W and also within 120 nm north of axis west 
of 136W.

...DISCUSSION...   

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Strong to near gale force northwest winds are observed across 
the discussion waters north of 28N and west of the Baja 
Peninsula, with seas of 10 to 12 ft in northwest swell. A new 
set of northwest swell will propagate into the northeast waters 
on Friday building seas to 10 to 14 ft, with the maximum of these
seas expected near 31N120W. These seas will slowly subside 
Friday night through Saturday. Seas of 8 to 10 ft in northwest 
swell will propagate as far south as 21N between 114W and 130W on
Saturday, then shrink in coverage on Sunday. Another pulse of 
northwest swell is forecast to reach near 30N120W on Mon night.

Gulf of California: Mostly gentle to moderate southwesterly flow 
is expected through Friday night, with brief fresh to locally 
strong breeze possible over the gulf waters north of 30N on Sat 
morning.

Gulf of Tehuantepec: Gentle to moderate southerly flow expected 
this weekend with fresh north winds possible near daybreak on 
Monday.

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR...

Mostly a gentle onshore breeze is expected during the next few 
days becoming offshore along the coasts at night. Combined seas 
of 4 to 5 ft in mainly southwest swell will continue through 
these waters through Sunday. Wave model guidance forecasts large 
long period southern hemispheric southwest swell to approach the 
offshore waters of Ecuador on Monday.

REMAINDER OF THE AREA...

A 1029 mb high pressure system is analyzed just north of the 
area at 34N138W, with a ridge extending southeastward to 
25N127W to near 19N117W. High pressure covers the area north 
of 14N west of 120W. Strong northwest winds along with seas 
of 8 to 12 ft will continue to the north of 28N east of 125W to 
waters outside the 250 nm range of the Mexican coast through 
early on Saturday before they begin to slowly subside. Fresh 
northeast trades are expected between the ridge and the ITCZ, 
with seas of 7 to 8 ft in mixed northeast and northwest swell 
through Saturday. Southern hemispheric swell resulting in seas
of 8 to 10 ft will reach the equator between 98W and 129W on 
Friday, and to the south of a line from the equator at 121W to 
11N112W to 09N102W on Saturday. 

Over the tropics, mid/upper level ridging is supporting clusters
of convection along and near the ITCZ. This activity has trended
in becoming more widespread during the past few days, and is 
forecast to remain quite active through Saturday as ridging
aloft remains in place while weak westward moving perturbations
migrate westward through the ITCZ.

$$
Aguirre