AXPZ20 KNHC 211511
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Tue Mar 21 2023
Tropical Weather Discussion for the eastern Pacific Ocean from
03.4S to 30N, east of 120W including the Gulf of California, and
from the Equator to 30N, between 120W and 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
Pacific Gale Warning for far northern waters behind a cold front:
A cold front analyzed from near Point Conception, California
through 30N123W to 25N130W to 21N140W. Strong high pressure
building in behind the front with cold-air advection is
supporting strong to gale-force W to NW winds north of about 29N
west of the front to around 137W, with strong to near-gale force
winds north of 25N. As the front moves E away from the area,
winds will diminish below gale force late tonight into early Wed.
Pacific Significant Swell Event: The other hazard from the
aforementioned cold front will be large NW swell following the
front, with seas reaching up to around 19 ft this afternoon into
early Wed along and north of 30N. Wave heights in excess of 12
ft will reach as far south as 23N Wed before subsiding. Looking
ahead, even as the NW swell decays Thu into Fri, it will mix with
increasing shorter-period waves associated with northeast trade
winds along with combined significant wave heights reaching 12 ft
mainly from 05N to 25N and west of 110W. These seas of around 12
ft may continue through Sat night before decaying somewhat.
Please read the latest High Seas Forecast at
https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and Offshore
Waters Forecast at www.nhc.noaa.gov/marine/offshores.php for
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
A surface trough extends from 08.5N78W to 05N90W. The ITCZ
extends from 05N90W to 00N98W to 03S101W to 03S120W. Scattered
moderate isolated strong convection is noted from 01N to 03N
between 88W and 90W, and from 01N to 07N between 115W and 137W.
Scattered moderate convection is noted from 01N to 04N between
94W and 96W, and from 01N to 03N between 105W and 110W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
Fresh to near gale-force N winds are in the Gulf of Tehuantepec
due to high pressure building N of the area, with seas of 5 to 8
ft there. A cold front is just NW of the area. Fresh to strong
SW to W gap winds are in the northern Gulf of California N of 30N
ahead of the front along with 3 to 6 ft seas, with similar winds
just beyond 60 nm offshore Baja California Norte. Mainly gentle
anticyclonic winds around a ridge ahead of the front are across
the remainder of the offshore waters of Mexico, along with seas
of 2 to 4 ft which are starting to build in NW swell offshore
Baja California Norte.
For the forecast, fresh to strong N winds in the Gulf of
Tehuantepec will diminish by late afternoon, with another pulse
late tonight. The cold front just NW of the area will cross the
Baja California Peninsula and Gulf of California tonight through
Wed night. Fresh to strong SW to W gap winds will be in the
northern Gulf of California ahead of this cold front with similar
winds offshore Baja California Norte, and fresh to strong W to
NW winds will occur offshore Baja California behind the front
through the end of the week. Fresh to strong winds will develop
behind the front in the central and southern Gulf of California
to near Cabo Corrientes Thu night through early Sat. Meanwhile,
large NW swell of 8 to 12 ft will arrive behind the front
offshore Baja California tonight through the end of the week,
with a reinforcing set this weekend.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
Fresh to locally gap winds are occurring across the Gulf of
Papagayo due to high pressure north of the area, with seas of 5
to 7 ft there. Moderate to fresh gap winds are ongoing in the
Gulf of Panama. Elsewhere, light to gentle variable winds prevail
over the offshore waters of Central America and northern South
America, along with seas of 3 to 5 ft mainly due to a long-
period south to southwest swell.
For the forecast, fresh to locally strong gap winds will prevail
across the Gulf of Papagayo and the coast of Nicaragua through
Fri night, then again Sat night. Moderate to fresh N to NE winds
can be expected over the Gulf of Panama through Fri morning.
Gentle to moderate winds and slight seas will prevail elsewhere
through the period.
REMAINDER OF THE AREA...
Please see Special Features section above for details on a Gale
Warning in effect for the waters well W of Baja California
Norte through tonight into early Wed, as well as significant
seas over the northern waters continuing into mid-week.
A cold front extends from near Point Conception, California
through 30N123W to 25N130W to 21N140W. Ahead of the front, fresh
to strong SW winds are N of about 27N. Behind the front, fresh to
strong NW winds are occurring around the above mentioned area of
strong to gale-force winds, and associated seas are 8 ft or
greater. Weak high pressure ridging is the main feature over the
area to the south of the front. Moderate to locally fresh trade
winds mainly from near 03N to 20N west of 130W are supporting
combined seas of 5 to 7 ft in that area. Mainly gentle to
moderate winds and slight seas are noted elsewhere, except seas
to around 7 ft from 03N to 15N between 90W and 105W due to an
earlier Gulf of Tehuantepec gale event.
For the forecast, the cold front will move east across the
northern and central waters through Wed as its southern part
weakens and dissipates. As high pressure builds in behind this
front, trade winds will increase from around 03N to 24N W of
110W, supporting fresh to strong speeds for the latter half of
the week into the upcoming weekend. Mainly gentle to moderate
winds and slight to moderate seas will prevail elsewhere.