Tropical Weather Discussion
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AXPZ20 KNHC 281545

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Fri Apr 28 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
1430 UTC.


A surface trough axis extends from 10N87W TO 07N103W TO 05N123W,
where the ITCZ forms, and then continues WSW FROM 05N123W TO
02.5N132W TO beyond 03N140W. Scattered to locally numerous
moderate to strong convection is noted from 02N to 07N between
83W and 106W. Scattered moderate convection is noted from 03.5N
TO 06N E OF 79W. Widely scattered moderate isolated strong
convection is noted within 150 nm either side of line from
07.5N126W TO 11N140W.



Strong to near gale force northwest winds continue across the
discussion waters from 28N to 30N and west of the Baja Peninsula
to near 125W , with seas of 9 to 13 ft in northwest swell. These
winds and seas will persist through Saturday as a strong
pressure gradient remains over the area between high pressure to
the west, and low pressure over the southwestern United States.
Seas of 8 to 10 ft in northwest swell will propagate as far
south as 20N between 114W and 130W on Saturday before conditions
begin to slowly improve over these waters Saturday night into

Gulf of California: Mostly gentle to moderate southwesterly flow
is expected through Friday night, with brief fresh to locally
strong northerly winds possible over the gulf waters north of
30N briefly this afternoon and evening, and then Sat as a cold
front passes across the area. The fresh to strong NW winds with
and behind this front will shift S and into central portions Sat
through Sat night and gradually build seas 5-7 ft before an
improving trend begins Sunday.

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

Elsewhere, mainly gentle to moderate winds will prevail with seas
primarily between 6 to 8 ft.


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 tonight. Wave model guidance forecasts
large long period southern hemispheric southwest swell of 5 to 7
ft to approach the offshore waters of Ecuador on Saturday, and
again on Monday night.


A 1028 mb high pressure system remains just north of the area
near 35N136W, with a ridge extending southeastward to 20N120W to
near 15109W. This high pressure system covers the area north of
the ITCZ and west of about 115W. A tight pressure gradient
between the high and low pressure over the southwestern United
States will continue to support strong northwest winds along
with seas of 8 to 13 ft north of 28N east of 125W through
Saturday, before they begin subside through the remainder of the
weekend. Fresh northeast trades are expected between the ridge
and the ITCZ W of 125W over the next several days, with seas of
6 to 8 ft in mixed northeast and northwest swell expected
through Saturday night. Southern hemispheric swell will
propagate across the waters south of 10N between 95W and 120W
today through early Sunday, resulting in seas of 8 to 10 ft.

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