AXPZ20 KNHC 172146
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Sat Nov 17 2018
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 0600 UTC surface analysis and satellite imagery through
.INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends W off the Pacific coast of Colombia
at 08N78W across the Gulf of Panama to the Pacific coast of
Costa Rica at 09N85W and then turns SW to 06N95W where
scatterometer winds indicate a transition to an ITCZ, which then
continues NW interrupted by a 1010 mb surface low at 10N117W,
then wiggles W to beyond 09N140W. Scattered moderate isolated
strong convection is noted within 120 nm either side of a line
from 08N100W to 10N116W to 08N125W to 09N137W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
Gulf of Tehuantepec...Strong to near gale force northerly winds
will pulse across the gulf waters and as far S as 13N95W through
late Tue. Model guidance suggests stronger drainage flow on Tue
night and even hints at minimal gale force conditions developing
briefly on Tue evening.
Gulf of California: Light and variable winds expected through
Sun evening. Moderate NW winds forecast across the entire gulf
waters on Sun night into Mon morning, then the pressure gradient
will relax with light NW flow through Mon night.
A weak NW to SE ridge extends across the Mexican offshore waters
W of 100W, with gentle to moderate anticyclonic flow forecast
around the meandering ridge through at least the middle of next
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
Gulf of Papagayo...Fresh to locally strong NE winds, with seas
building briefly to 8 ft well downstream, are expected through
the middle of next week with the strongest drainage flow
reaching as far SW as 10.5N88.5W.
Light to locally moderate northerly flow is forecast elsewhere N
of the monsoon trough, while moderate southwesterly monsoonal
flow, with 4 to 6 ft seas, is forecast S of the monsoon trough
through the middle of next week.
REMAINDER OF THE AREA...
A 1010 mb surface low is analyzed at 09.5N117W surrounded by
a large area of long period northeasterly swell that is mixing
with cross-equatorial swell across the waters S of 14N between
93W and 120W. This swell will gradually subside to less than 8
ft by the middle of next week as the surface low progresses
westward. Model guidance suggests that a surface trough will
develop near 09N117W early next week with an area of 8 ft seas
continuing within 420 nm E of the trough axis as it shift W
along the ITCZ.
A cold front extends from 32N138W to 26N140W accompanied by a
fresh SW-W-NW wind shift, and 7 to 10 ft seas W of the front in
long-period NW swell. The front will weaken early next week, but
still reach the Baja Peninsula on Wed night. The associated NW
swell will subside to less than 8 ft on Mon night.
Another round of NW swell, in the form of 7 to 11 ft seas, will
reach 30N140W late Mon night. A tightening pressure gradient
will result in strong W winds N of 30N between 125W and 140W on
Tue night into Wed. A ridge will set up from 29N140W to 17N106W
on Wed night with strong NE trades, with seas to 11 ft, forecast
from 11N to 22N W of 127W on Thu, surrounded by NW resulting in
7-9 ft seas across the waters elsewhere N of the ITCZ W of