Tropical Weather Discussion
Issued by NWS
AXPZ20 KNHC 050329
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
215 UTC Mon Dec 5 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
Based on 0000 UTC surface analysis and satellite imagery through
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough axis extends from 12N102W to 09N109W to
08N125W. The ITCZ reaches from 08N125W to 07N135W to 10N140W.
Scattered moderate convection is noted within 120 nm north of the
monsoon trough between 110W and 130W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
Gulf of California: Fresh breezes over the northern Gulf will
diminish over night. Light to gentle southerly flow is expected
north of 29N on Monday, with light and variable winds forecast
across the Gulf waters south of 29N. The next cold front is
expected to pass across the northern gulf on Wednesday, with fresh
to locally strong post-frontal flow forecast on Wednesday night.
Moderate to fresh northwest to north winds persist off Baja California,
along with 7 to 9 ft seas in northwest swell. The pressure gradient
will gradually slacken through Tuesday allowing for the winds to
diminish to a gentle to moderate northerly breeze on Monday, with
combined seas in the 4 to 6 ft range, except for higher seas of 7
to 9 ft in northwest swell north of 26N around Guadalupe Island
Monday and Tuesday.
Farther south, jet dynamics aloft has been supporting scattered
showers and thunderstorms off the coast of Mexico, along a
persistent surface trough from 16N101W TO 13N103W. While this
activity has dissipated for now, it may reform overnight off the
Mexican coast between Petatlan and Acapulco. The trough is
forecast to gradually shift east- southeast through the next
couple of days while weakening.
Gulf of Tehuantepec: The next strong gap wind event is expected
to begin beyond 48 hours early on Thursday afternoon. Northerly
winds across the Gulf will quickly strengthen to minimal gale
force late Thursday afternoon, with the gale conditions possibly
increasing to strong gale winds through early on Saturday. Along
with these winds, seas are forecast to rapidly build to large
heights of around 17 to 21 ft.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
Gulf of Papagayo: Moderate to locally fresh nocturnal northeast
to east winds are expected to begin again late Tue night.
Light to gentle northerly winds, except for light and variable
winds to the east of 100W are present elsewhere north of the
monsoon trough, with seas in the 4 to 6 ft range. A gentle to
moderate southwest flow is observed to the south of the monsoon
trough, with seas in the 5 to 6 ft in long-period southwest.
REMAINDER OF THE AREA...
A ridge extends from 1028 mb high pressure near 36N136W to
18N115W near Clarion Island. The high pressure is supporting a
broad area of moderate to fresh trade winds from roughly 10N to
25N west of 125W. A recent altimeter pass confirmed 8 to 10 ft
seas, likely due to long period northwest swell lingering over the
area. The high will weakens ahead of a deep low pressure system
moving from north of Hawaii toward the Pacific Northwest region
over the next several days. Trades winds will diminish further
through mid week as the high pressure weakens. The northwest swell
will likewise decay below 8 ft over most of the area through mid
Meanwhile scattered showers and thunderstorms persist along to the
north of the monsoon trough between 115W and 125W, enhanced in
part by jet dynamics aloft.