AXPZ20 KNHC 071500
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1500 UTC Wed Dec 7 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 1200 UTC surface analysis and satellite imagery through
Gulf of Tehuantepec Gale Warning: Winds will be light and variable
through Thursday afternoon, with northerly winds at night with
nocturnal drainage flow. A strong cold front will charge through
the Gulf of Mexico north of the area by the end of the week with
high pressure ridging surging down eastern Mexico. Northerly winds
will rapidly increase to fresh to strong in the Gulf of
Tehuantepec by Thursday evening, then increasing to minimal gale
force by early Friday. Gale force winds will persist through
Saturday night. Winds will peak around 40 kt Friday night. Seas
will build to up to 18 ft by Friday night. Gale force winds will
diminish by early Sunday, however, another gale force wind event
is possible early next week.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough axis extends from 09N77W to 07N98W to low
pressure near 10N107W to 10N120W. The intertropical convergence
zone axis extends from 10N120W to 08N140W. Scattered moderate from
07N to 08N between 78W and 81W, from 08N to 11N between 94W and
97W, from 11N to 13N between 107W and 113W, from 07N to 10N
between 113W and 120W, and from 08N to 10N between 128W and 131W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
Gulf of California: Broad and weak low pressure is in the northern
gulf near 30.5N114W with troughing reaching to the southwest
across Baja California norte. A small area of fresh southwest
winds is possible from 29.5N to 30.5N to the east of the trough. A
weak cold front will clip by the northern gulf through the day
today causing winds to become northerly across the basin. A tight
pressure gradient will then setup Thursday through Friday night
with northerly flow increasing to fresh to strong across the
central and southern gulf. Seas will build to 5 to 7 ft as a
A ridge will meander across the area from 23N116W to 18N107W
today, then shift southwest some tonight. Gentle to moderate
anticyclonic flow is forecast around the ridge through the end of
the week. Combined seas, mainly northwest swell, of 4 to 7 ft
will subside from northwest to southeast today. Winds offshore of
Baja California norte will increase to fresh to strong north of
27N Friday night through the weekend as the gradient tightens.
Fresh seas will build to 7 to 9 ft as a result.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
Gulf of Papagayo: Moderate to locally fresh nocturnal east-
northeast winds are expected the next couple of nights, increasing
to fresh to strong Friday night and Saturday night as the gradient
across the region tightens. Seas will build to up to 8 ft just
downwind of the gulf with the strongest winds.
Mostly light to gentle northerly winds, and combined seas of 2
to 4 ft, are occurring elsewhere north of the monsoon trough
which is meandering along about 10N. Light to moderate southwest
flow is observed to the south of 10N, where combined seas of 3 to
5 ft in long period southwest swell are expected this week.
REMAINDER OF THE AREA...
A 1022 mb surface high is analyzed near 28N128W with a ridge
extending southeast to near 18N107W. The surface high will shift
southeast to near 30N124W later today, and will strengthen some
blocking the southern advance of a cold front, causing it to
stall from 32N137W to 31N140W on Thursday, and then further
weaken as it drifts west on Thursday night.
Gentle to moderate northwest to north flow is expected northeast of
the ridge today and on Thursday. Moderate to locally fresh northeast
trades are forecast south of the ridge, with the fresh winds
mainly just to the north of the ITCZ. Seas of 5 to 7 ft today
will build to 7 to 9 ft late this week across the deep tropics
north of the ITCZ.