AXPZ20 KNHC 280926
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0900 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
Based on 0600 UTC surface analysis and satellite imagery through
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
A surface trough axis extends from 09N84W TO 06N96W TO 06N110W,
where the ITCZ forms, and then continues WSW through 05N125W TO
beyond 04N140W. Scattered moderate convection is from 03N to 07N
between 82W and 100W, and from 02N to 09N between 100W and 118W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
Strong to near gale force northwest winds continue across the
discussion waters from 28N to 30N and west of the Baja
Peninsula, with seas of 10 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
21N between 114W and 130W on Saturday. Conditions will improve
over these waters Saturday night into Sunday.
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 on Sat morning as a cold front passes across the area.
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.
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 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.
REMAINDER OF THE AREA...
A 1029 mb high pressure system remains just north of the area
near 35N138W, with a ridge extending southeastward to 20N120W to
near 13N110W. 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 the next several days, with seas of 6 to 8 ft in
mixed northeast and northwest swell through Saturday. Southern
hemispheric swell will propagate across the waters south of 10N
between 95W and 120W today through Saturday, resulting in seas of
8 to 10 ft.