000
AXPZ20 KNHC 032209
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Sun Dec 3 2017

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 
2100 UTC.

...SPECIAL FEATURES...

Afternoon scatterometer data indicates that gale force E winds 
have developed N of a cold front across the NW corner of the 
discussion area, that extends from 28N140W TO 27.5N136W TO 
23N134W. The gale force winds are occurring W of 137.5W and 
extend into the adjacent waters W of the area that wrap into a 
1012 mb low pressure center near 27N142W. The low will shift SSW 
this evening and tonight, and allow the front to sink slightly S 
with it, thus reducing the pressure gradient. The E gales are 
expected to end within 12 hours.  Meanwhile, a trough is 
analyzed to the S from 13N140W to 21N136W. This trough will 
drift NW through early week, resulting in a tight pressure 
gradient, and increase winds to fresh to strong on the NE side 
of it. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

A trough axis extends from northern Colombia near 09N75W to low 
pressure near 06N79W. The monsoon trough extends from the low to 
07N88.5W TO 06N105W. The ITCZ then continues on to low pressure 
near 09N116W to 07N124W to 13N140W. Scattered moderate to strong 
convection is from 09N TO 15N between 110W AND 120W, and 
from 15N TO 24N between 129W and 137W. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Gulf of California: Strong high pressure will build well N of 
the area, over the U.S. Great Basin and northern Rockies through
the early part of the week. This will support strong northerly
winds over the northern Gulf of California by early Mon, 
spreading into the central Gulf Mon night and early Tue, and the 
southern Gulf Tue night into Wed. Seas are expected to build up 
to 10 ft across the north part of the basin by late Tue and to 6-
9 ft across the rest of the basin Wed through Thu. Winds may 
reach to near gale force over the northern Gulf Mon night and 
Tue, with strong easterly gap winds penetrating across areas in 
Baja California Norte into the Bay of San Sebastian. The winds 
will diminish slightly Wed, but will increase again late in the 
week as reinforcing high pressure builds N of the region, and 
produce another period of strong to near gale force winds.

Gulf of Tehuantepec: Higher pressure N of the area continues to 
support fresh to strong gap winds through the Gulf of 
Tehuantepec. Associated seas are 7-10 ft this afternoon and 
include shorter period swell generated from the strong gap winds 
reaching 200 to 300 nm downstream of the Gulf of Tehuantepec, 
mixed with longer period NW swell. The high pressure will weaken 
through tonight, allowing for the plume of stronger winds to 
shrink. Even so, winds will continue to pulse, mainly at night, 
to fresh to strong through Thu morning, possibly increasing to 
gale force by Thu night as a cold front pushes across the 
western Gulf of Mexico and through southern Mexico. Looking 
ahead, strong high pressure building N of the area behind a Gulf 
of Mexico cold front will supporting a persistent strong gale 
event across the Gulf of Tehuantepec through late in the week.

Elsewhere off the Pacific coast of Mexico, weak high pressure is
maintaining gentle to moderate breezes across the region. Long 
period NW swell is producing seas of 7 to 10 ft swell 
propagating across all open waters, except within 150 nm of the 
coast south of Los Cabos. The swell will gradually decay to less 
than 8 ft across all offshore waters by Tue.

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR...
  
Gulf of Papagayo: An earlier scatterometer pass indicated fresh
to strong winds feeding out from the Gulf of Papagayo. These 
winds will increase again during tonight. Seas downstream from 
the Gulf will build to 6 to 8 ft during the time of peak winds, 
subsiding slightly each afternoon and evening.

Elsewhere, light to gentle N to NE winds are expected N of the 
monsoon trough, and mainly moderate S to SW winds are expected to
the S of the monsoon trough. Seas are in the 4 to 6 ft range, 
but are expected to build to 5 to 7 ft in a SW swell to the 
S of the monsoon trough beginning this afternoon and into Mon.

REMAINDER OF THE AREA...

A 1010 mb low pressure remains embedded along ITCZ near 09N116W, 
racing WNW at 15-20 kt, and producing fresh to strong winds N of 
that area to 15N. Active convection across this zone is being 
initiated by these fresh to strong E winds. The low will 
dissipate and become an open trough within 24 hours, with 
associated winds diminishing to 20 kt or less by early Tue. 

Otherwise, NW swell greater than 8 ft covers almost the entire 
discussion waters beyond 250 nm offshore of Central and South
America. These seas will gradually decay through the early part
of the week.

$$
Stripling