000
AXPZ20 KNHC 210928
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
848 UTC Thu Dec 21 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 0600 UTC surface analysis and satellite imagery through
0830 UTC.

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

The ITCZ axis extends from 07N102W to 10N120W to beyond 09N140W.
Scattered moderate and isolated convection is located from 10N to
17N between 112W and 124W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...


Gulf of California: A cold front has just reached Baja California
Norte and will be reaching the Gulf of California shortly. NW
winds behind the front should be fresh to strong through Saturday
before diminishing. Peak wave heights should reach up to 8 ft on
Friday in the central Gulf. Some fresh to briefly strong winds
will emerge over the Pacific coast of Baja California in the gaps
between the highest terrain.  

Gulf of Tehuantepec: An 0354 UTC ASCAT scatterometer pass
indicated fresh breeze northerlies in the Gulf of Tehuantepec
this evening. A new Tehuantepec gap wind event should occur
starting early Sunday, due to a strong cold front pushing across
the Gulf of Mexico. Guidance has backed off some since 
yesterday, with the 00Z GFS suggesting a 40 kt peak Sunday 
evening and the 00Z ECMWF indicating only 30 kt peak Monday 
morning. Have taken a blend of the two for wind grids, so 
expected gale conditions early Monday through afternoon Tuesday. 
12 ft seas or greater are likely to occur on Monday and Tuesday 
in the Gulf with maximum seas around 15 ft early Tuesday.

NW near gale winds just offshore of southern California will
induce NW swell east of Baja California Norte. Peak seas of 8 to
9 ft should be expected through tonight.

Elsewhere winds are fresh breeze or weaker and seas less than 
8 ft through Monday.

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR...

NE fresh to strong breeze is likely occurring in the Gulf of
Papagayo, though no recent observation has been available in the
area. These should diminish by Friday morning.

Elsewhere winds are fresh breeze or weaker and seas less than 
8 ft through Monday.

REMAINDER OF THE AREA...

NE moderate to fresh winds prevail over the waters from the ITCZ
to 30N, driven by high pressure centered north of the region. 
These winds support 6 to 8 ft seas in a NW swell between 20N and
25N west of 130W.
 
High pressure will build southeastward toward California on 
Friday while low pressure develops west of our waters near 
roughly 25N145W. The pressure gradient between these two 
features will support strong to near gale conditions north of 23N
west of 135W on Friday. Combined sea heights up to 14 feet from
SE wind waves and NW swell are expected on Saturday. The NW 
swell will push southeastward - slowly - from Sunday through 
Tuesday after the main low moves northward out of our area late
on Saturday. This swell is expected to gradually weaken to below
8 ft.

$$ 
Landsea