AXPZ20 KNHC 300852
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Mon Nov 30 2020
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 0930 UTC.
Gulf of Tehuantepec Gale Warning: The next gap wind event over
the Gulf of Tehuantepec is expected to commence late tonight into
early Mon morning as strong cold front currently moving across
the western Gulf of Mexico reaches the Isthmus of Tehuantepec.
High pressure building behind the front will provide a tight
pressure gradient across the area, and bring an increase in
winds funneling into the Gulf of Tehuantepec. Winds will rapidly
increase to strong gale force by Mon afternoon and reach 40-45
kt by Mon evening. Seas will peak near 20 ft by Mon night. Marine
interest transiting across or in the vicinity of the Gulf of
Tehunatepec should be aware of this upcoming gap wind event, and
take necessary action to avoid these hazardous marine conditions
over the affected waters. Winds are forecast to diminish below
gale force on Tue night. Please, see the latest High Seas
Forecast issued by the National Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details.
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from 08N78W to 08N99W to a 1010 mb
low pressure near 06N118W to 1009 mb low pressure near 10N129W
to 08N134W. The ITCZ continues from 08N134W to beyond 07N140W.
Scattered showers are in the vicinity of the monsoon trough
between 89W-134. Scattered moderate convection are noted in
near the 1009 MB low from 06N-16N between 123W-134W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
A Gale Warning is in effect for the Gulf of Tehuantepec. Please,
see Special Feature Section for more details.
A ridge prevails across the offshore waters of Baja California,
anchored by high pressure of 1025 mb centered near 33N130W. This
system is producing gentle to moderate NW-N winds. Seas are in
the 5-7 ft range. Long period NW swell will reach the waters N of
Punta Eugenia by Tue building seas to 8-10 ft by Tue night.
Strong high pressure over the Great Basin of U.S. supports fresh
to strong NW winds in the Gulf of California. Sea heights are in
the 4-6 ft range. A recent scatterometer pass confirmed the
presence of these winds, forecast to persist trough Mon morning.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and
WITHIN 750 NM OF ECUADOR...
Fresh to strong NE to E winds are expected in the Gulf of Papagayo
Mon night through early Wed morning with seas building to 9 ft.
Mainly moderate to fresh NE winds will prevail the remainder of
the forecast period. Seas generated by a strong gap wind event in
the Gulf of Tehuantepec will propagate across the offshore
waters of Guatemala and El Salvador Mon night through Tue night.
Elsewhere, moderate S to SW winds are expected S of the monsoon
trough with mainly gentle easterly winds N of the monsoon trough.
REMAINDER OF THE AREA...
A ridge dominates the northern forecast waters and extends beyond
the Revillagigedo Islands to near 15N112W. The pressure gradient
between the ridge and lower pressure within the monsoon trough,
and in the vicinity of the ITCZ, is supporting moderate to fresh
trade winds north of 10N and west of 120W. Seas are generally 6-8
ft across this area.
A surface trough is analyzed from 20N128W to 15N131W to 10N128W.
An area of moderate to isolated strong convection is on the E
side of the trough covering from 12N to 15N between 122W and
128W. Moderate to fresh NE winds are noted per scatterometer
data near the northern end of the trough axis forecast to drift
westward while weakening. A well defined swirl of low clouds is
noted on visible satellite imagery near 07N118, and a surface low
pressure of 1013 mb is analyzed in this position along the
monsoon trough. Fresh winds are seen within about 60 nm on the E
side of the low center.
Large NW swell will continue to propagate across the forecast
waters. A new set of long period NW swell will reach the NW
corner of the forecast region on Mon building seas to 8-10 ft N
of 11N and W of a line from 30N117W to 20N120W to 11N127W by Tue
afternoon. Another and larger NW swell event will begin to
propagate across the NW waters on Wed, with building seas of
12-16 ft W of a line from 30N133W to 20N140W by Wed night.