Tropical Weather Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
AXPZ20 KNHC 180322
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
320 UTC Sat Nov 18 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
0315 UTC.

INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

The monsoon trough extends from 09N84W to 10N92W to 09N105W
where it transitions to the intertropical convergence zone, and
extends through 11N125W to beyond 11N140W. Scattered moderate
isolated strong convection is noted from 09N to 11N W of 137W.
Scattered moderate convection is noted from 11N to 14N between
123W and 127W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

High pressure is forecast to build in from the N on Sat with
current gentle to moderate northerly winds across the offshore
waters W of Baja California, becoming moderate to fresh NW to N
winds and building seas of 6-7 ft N of 25N Sat morning through
late Sun.

Gulf of Tehuantepec: A final pulse of strong northerly drainage
flow, with seas building to a max of 9 to 10 ft, are forecast
late tonight into early Sat morning, diminishing afterward as the
high pressure over the eastern slopes of the Sierra Madre
mountains weakens. Another strong cold front will enter the Gulf
of Mexico late Sat, followed by strong high pressure building
into northeast and central Mexico through Sun. This will support
a return of strong gap winds in the Gulf of Tehuantepec by early
Sun, reaching gale force Sun afternoon through Mon morning. A
gale warning is now in effect for the area in the latest High
Seas forecast. NWP guidance indicates winds of 35-40 kt and
building seas of 14-15 ft by Sun night.

Gulf of California: Strong high pressure building north of the
area over the Great Basin will support fresh to strong NW winds
across the northern Gulf of California by mid-day Sat, spreading
into the central and southern portions of the gulf late Sat into
Sun, before diminishing late Sun. Seas are forecast to build to 6
or 7 ft across the central gulf early on Sun.

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

Gulf of Papagayo:  Moderate to locally fresh NE drainage winds
are forecast during the overnight hours through the middle of
next week with seas building to 5 ft downstream near 10N87W.

Light and variable winds, and 3 to 5 ft seas, are expected
elsewhere to the N of 09N, while moderate to locally fresh
southerly winds, and 4 to 7 ft seas, are forecast S of 09N
through the middle of next week.

REMAINDER OF THE AREA...

A pair of 1017 mb surface lows are centered near 28N132W and
28N128W. The associated dissipating front enters the forecast
waters near 30N128W and extends to 20N138W. Earlier ASCAT-A and
ASCAT-B passes from 1800-1900 UTC today indicated NE winds of 20
to locally 25 KT N of 30N with lighter winds in the discussion
area. A pair of altimeter passes showed 8 to 9 ft seas in the
wake of the front. The complex lows are forecast to drift in
place and weaken significantly as the front dissipates by early
Sat.

Strong SE to S return flow will develop across the NW waters N
of 27N W of 138W by Sat night, in advance of the next cold front
forecast to approach the far NW corner of the area Sun night.
The front will move slowly with the strong S to SW flow persisting
over the NW waters on Mon. At that time, expect fresh to strong
winds and seas of 8 to 11 ft covering roughly the waters N of
24N W of 136W.

Farther S and N of the ITCZ/Monsoon trough, expect gentle to
moderate trade winds and 4 to 6 ft seas through Sat, with moderate
to fresh trades and seas of 6 to 7 ft by Sat evening into Sun.

$$
Cobb


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.