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Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 192149

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 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 1800 UTC surface analysis and satellite imagery through 
2030 UTC. 


Gale Warning: A cold front along a position from 30N131W to 
21N140W is preceded by strong southerly flow north of 24N and 
within 240 nm to its east, along with seas of 8 to 11 ft. A 
deepening surface low pres system currently northwest of the 
area will drop southeastward tonight behind this initial cold 
front dragging 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 0900 UTC on Tue, with 
associated seas of 15 to 16 ft. The low pres will lift north of 
the area on Tue afternoon and winds will diminishing to 20 kt to 
30 kt, and to 20 kt or less late Tue night. The associated NW 
swell, in the form of 8 to 9 ft seas will propagate 
southeastward through the waters covering the area west of a 
line from the northern Baja peninsula to 07N129W early on Sat. 
Please refer to the Pacific high seas forecast for more details 
on this upcoming event under AWIPS/WMO headers MIAHSFEP2/FZPN03


A surface trough extends from 08N83W to 04N90W to 05N103W where 
the ITCZ axis begins and continues along 05N103W to 06N120W to 
06N140W. Scattered moderate isolated strong convection is noted 
from 05N to 09N between 108W and 125W.



Surface high pressure of 1020 mb west of the northern Baja 
Peninsula extends a ridge axis S to near 19N. This ridge will 
shift slightly to the southeast through Tue, thus supporting 
fresh to locally strong northerly winds on Jalisco, Mexico 
offshore waters between 105W and 107W. Gentle to moderate 
northerlies are over the Baja offshore waters diminishing to 
light to gentle Tue night as the ridge weakens. These winds 
along with 3 to 5 ft seas will continue through early Friday 
morning when winds will increase to moderate again due to a 
strong ridge building northwest of the area.

Gulf of California: Fresh to locally strong northwest flow is 
forecast across the southern half of the gulf waters tonight 
through Tuesday evening accompanied with seas to 7 ft.

Gulf of Tehuantepec: Strong to near-gale north flow will surge 
through the gulf waters on early Wed morning, increasing to 
minimal gale force Wed night. Gale conditions are then expected 
to continue through Fri morning, with seas building to a maximum 
of around 12 ft. 


Gulf of Papagayo: Fresh to locally strong NE nocturnal winds are 
forecast starting Tue night and continuing through Wed evening 
with seas building to 7 ft downstream. A stronger drainage event 
is forecast to begin early Thu morning, and persist into the 
upcoming weekend with seas building to 10 ft.

Gulf of Panama: Fresh to strong north nocturnal winds are 
forecast starting early Thu morning through Sat night with seas 
building to 8 ft.

Light to gentle offshore flow will prevail elsewhere. 


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 28N and west of 119W.
These clouds and precipitation will continue to advance eastward 
towards southern California and the northern and central Baja 
California through Wed per model moisture guidance fields.