000
AXPZ20 KNHC 010357
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Fri Dec 01 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 0000 UTC surface analysis and satellite imagery through 
0200 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning: A modest high pressure ridge 
extends SSE across eastern Mexico and the far western Gulf of 
Mexico to the Tehuantepec region, and is producing a tight 
pressure gradient there. Minimal gale force northerly winds 
across the area waters late this afternoon are slowly beginning 
to increase this evening, and are expected to peak again tonight 
at 30 to 40 kt through early Friday morning. Minimal gale force 
winds are then expected to continue through Friday night before 
diminishing to 20-30 kt late Saturday morning. During this 
extended gale event, seas are forecast to peak at 12-14 ft early 
Friday, with downstream seas towards the SW of 8 ft and higher 
reaching as far as 650 nm offshore. 

INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 10N74W TO 
10N83W TO 07N89W TO 07N105W, where it transitions to the ITCZ 
and continues on to 09N120W TO beyond 08N140W. Scattered 
moderate to strong convection is located from 07N to 10N between 
78.5W and 84W, from 06.5N to 11N between 94W and 102W, and from 
08N to 09N to the W of 138W. Widely scattered moderate isolated 
strong convection is located from 09N to 17N between 112W and 
132W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Ridging extending SE across the region to near 17N107W will 
maintain gentle to moderate breezes across the entire offshore 
area through early next week. Long period northwest swell 
propagating across the waters offshore of Baja California the 
past 2 days has reached to near 105W, and is producing seas of 6 
to 9 ft across the waters from Baja California sur to south of 
Manzanillo. Reinforcing NW swell has moved into the waters of 
north and central Baja California and built throughout the 
afternoon, producing combined seas 8 to 13 ft. This new pulse of 
swell will reach as far south as the Revillagigedo Islands at 10 
ft swell by early Sat, then decay below 8 ft by late Mon. 

Looking ahead, a cold front is forecast to sweep across the SW 
U.S. Sunday night through Monday night and will force strong 
NWly winds through the full length of the Gulf of California 
Monday through Tuesday. Latest computer models suggest gale force 
winds could impact much of the Gulf and build seas to 8-12 ft by 
late Tuesday. 

Please see Special Feature section for detail concerning the 
gale warning in the Gulf of Tehuantepec.

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR...
  
Gulf of Papagayo: A modest pressure gradient between high 
pressure over the western Gulf of Mexico and lower pressure 
across the southwest Caribbean is producing fresh offshore gap 
winds across the Papagayo region. These winds will be enhanced 
with overnight drainage effects for the next few days, peaking 
near 25 kt during the late night through late morning hours. 
Seas downstream will build to 6 to 8 ft during the peak winds, 
with the winds and seas diminishing slightly each late afternoon 
through evening.

Light to gentle N to NE winds, and 4 to 5 ft seas are expected 
elsewhere through Sat N of the monsoon trough. Moderate 
southerly winds, and 4 to 6 ft seas, are forecast south of the 
monsoon trough. Northerly swell generated in the Gulf of 
Tehuantepec will reach the western part of forecast zone PMZ111 
(offshore waters of Guatemala and El Salvador) today through the
end of the week.

REMAINDER OF THE AREA... 

A large area of NW swell producing seas of 8 to 14 ft across the 
waters W of 116W will continue to propagate across the region, 
with the leading edge of 8 ft seas currently reaching from the 
offshore waters W of Cabo Corrientes to 10N108W to 00N128W, and 
will reach NW of a line from 18N112W to 00N140W Fri. Large NW 
swell currently moving through the N waters will spread SE and 
into the central waters through Fri night. High pressure north 
of the region has enhanced a broad zone of NE to E winds across 
the tradewind belt W of 125W through Fri. Seas of 8 to 12 ft are 
then expected to cover nearly the entire forecast waters S of 
30N W of 110W into Sun, and will start to fade below 8 ft 
through early next week. 

$$
Stripling