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Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 240233

0405 UTC TUE MAY 24 2016

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 0000 UTC surface analysis and satellite imagery through
0200 UTC.


The monsoon trough extends from 09N76W to 08N94W to 11N111W to
low pres 1010 mb near 09N119W to 08N127W then ITCZ continuing on
to low pres 1009 mb near 06N138W to beyond 05.5N140W. Widely
scattered to scattered moderate to strong convection is from 05N-
11N between 80W and 110W. Widely scattered moderate to strong
convection is within 150 nm of axis between 118W and 137W. 


A surface trough extends from southern California to far north
portions of Baja California Norte and the adjacent Gulf of
California. Gentle to moderate W to SW winds are expected across
the northern Gulf early tonight while variable light to gentle
winds are expected across the southern Gulf. Global models
continue to forecast a small area of low pressure developing
across the northern Gulf tonight and persisting through Tuesday
morning before dissipating, then redeveloping again Tuesday
night. Southwest to south winds across the southeastern half of
the low are expected to increase to 20 kt tonight and again
tomorrow night, with seas building 4-5 ft.  

Farther west, the persistent eastern Pacific ridge has weakened
during the past 24 hours as a new cold front is moving southward
to along 31N and approaching the northern boundary of the
discussion area. The ridge now extends from a 1028 mb high
center near 36N148W, southeastward over the remainder of the
area to near 16.5N108W.  The pressure gradient between the ridge
and lower pressure across Baja California is producing moderate
to fresh north-northwest winds across the near and offshore
waters of the Baja Peninsula. The late afternoon and evening
thermal contrast across the region is producing a fresh
seabreeze across segments of the Pacific waters near the
peninsula, where seas are running 6-7 ft, with small isolated
areas to 8 ft. Winds and seas will diminish slightly later
tonight as the peninsula quickly cools after sunset. The cold
front will sink south into north portions of the waters during
the next 24-36 hours and dissipate, with moderate high pressure
sinking southward along 140W. This will maintain similar ridging
across the area through Wednesday before the ridge strengthens
modestly Wednesday night through Friday, which will act to
freshen northwesterly winds along the Baja Peninsula. 

The pressure gradient between the ridge and the monsoon trough
to the south and southeast is promoting moderate to fresh trade
winds generally south of 22N and west of 120W. Several weak and
transient areas of low pressure are currently present along the
monsoon trough, and forecast to continue along the monsoon
trough through the week. Trade winds near these low centers may
occasionally increase to fresh to strong across the northern
portion, especially as convection flares up near the lows. Seas
across this trade wind zone will remain 5-7 ft through Wednesday
night before the ridge strengthens and winds and seas increase
slightly to near 20 kt and 6-8 ft through Thursday.

S OF 15N E OF 110W...

Light to moderate winds are expected to continue across the
forecast area south of the monsoon trough through the week, with
light and variable winds north of the trough. Combined seas of 3
to 5 feet will prevail through Wednesday morning, and then will
build to 4 to 7 feet for the remainder of the week as new cross-
equatorial southwesterly swell arrives. Active convection is
expected to continue about the monsoon trough through mid week.