Tropical Weather Discussion
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AXPZ20 KNHC 191605

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Mon Mar 19 2018

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
1545 UTC.


Gale Warning: A weakening cold front over the far northwest
portion of the area along a position from 30N134W to 22N140W is
preceded by strong southerly flow north of 25N and within 300 nm
to its east, along with seas of 8 to 10 ft. A deepening surface
low pres system currently northwest of the area will drop
southeastward tonight behind this initial cold front, and drag a
second cold front into the discussion area accompanied by a
strong to near gale southwest-west-northwest wind shift. The
pressure gradient will tighten around the southwest semicircle
of the low increasing the westerly winds to minimal gale force
winds in the range of 30 to 35 kt over the discussion waters
west of the front near 1200 UTC on Tue, with the associated seas
of 16 to 20 ft. The low pres will lift north of the area on Tue
afternoon, with associated winds diminishing to 20 kt or less
south of 32N on Wed evening. The associated NW swell, in the
form of 7 to 10 ft seas, will propagate southeastward through
the waters covering the area west of a line from the Central
Baja peninsula to 17N140W on Sat. Please refer to the Pacific
high seas forecast for more details on this upcoming event under


A surface trough extends from 08N82W to 04N90W to 06N102W, where
latest scatterometer winds indicate the ITCZ axis begins and
continues to 06N120W to 06N140W. Scattered moderate isolated
strong convection is noted from 04N to 09N between 107W and 124W
and within 165 nm S of the trough E of 94W.



A north-northwest to south-southeast ridge extending from
30N121W to 17N110W to 13N94W will shift slightly to the
southwest through Tue. Fresh to locally strong northerly winds
will set up south of 25N and east of the ridge briefly today and
tonight with the pressure gradient then relaxing some on Tue.
Light to gentle northerly winds and 3 to 4 ft seas are then
expected west of the Baja Peninsula through Wed.

Gulf of California: Moderate to fresh northwest flow is forecast
across the southern half of the gulf waters today, with narrow
swaths of strong northwest winds expected across the far
southern gulf waters late tonight. Seas may build to 6 ft in the
longer fetch waters.

Gulf of Tehuantepec: Strong north flow will surge through the
gulf waters on late Tue night, increasing to minimal gale force
Wed night. Gale conditions are then expected to continue through
Thu morning, with seas building to a maximum of around 11 ft
downstream from the gulf near 14.5N95.5W on Wed night.


Gulf of Papagayo: Fresh to locally strong NE nocturnal winds
will diminish to moderate winds this afternoon, then increase to
strong winds again briefly on Tue night with seas building to 7
ft downstream. A stronger drainage event is forecast to begin on
Wed night, and persist into the upcoming weekend.

Gulf of Panama: Fresh northerly winds will diminish to moderate
winds this afternoon. Fresh to strong north nocturnal winds are
expected to resume on Wed night.

Elsewhere, gentle to moderate offshore flow will prevail N of
07N while light to gentle SW winds are forecast S of 07N.


Please see see Special Features Section above for details on
upcoming gale force winds to impact the far NW portion of the
area in the short-term.

A very progressive pattern will continue to impact the the
northwest portion of the area well into this week. The deep
layer low pres system located to the northwest of the area and
its related trough is preceded by mid to upper level moisture in
the form of overcast cloudiness. Areas of rain along with
scattered showers and isolated thunderstorms under upper level
divergence that is present to the the east and southeast of this
low have moved over the area north of about 27N and west of 120W.
These clouds and precipitation will continue advancing eastward
towards the general area of southern California and also northern
and central Baja California through Wed per model moisture
guidance fields.

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