859
AXPZ20 KNHC 240929
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Tue Sep 24 2024

Tropical Weather Discussion for the eastern Pacific Ocean from
03.4S to 30N, east of 120W including the Gulf of California, and
from the Equator to 30N, between 120W and 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
0915 UTC.

...SPECIAL FEATURES...

Recently downgraded Tropical Storm John is inland the coast of
southern Mexico near 17.3N 100.0W. or about 30 miles north-
northwest of Acapulco, Mexico at 24/0900 UTC, moving northwest
at 7 kt. Estimated minimum central pressure is 990 mb. Maximum
sustained wind speed has diminished to 60 kt with gusts to 75 kt.
Seas are in the 11 to 19 ft range. Satellite imagery shows that
eye feature that was observed last night has now become obscured.
The imagery reveals numerous strong convection that is within 120
nm of the center in the NE quadrant, within 210 nm of the center
in the SE quadrant, within 150 nm of the center in the SW
quadrant and within 60 nm of the NW quadrant. John is forecast to
maintain a very slow westward motion. Very little motion is
forecasted over the next several days. Additional rapid weakening
is anticipated, and John is expected to become a tropical
depression later today. Tropical Storm John is expected to
produce 6 to 12 inches of rain with isolated totals around 15
inches across the coastal areas of Chiapas. In areas along and
near the Oaxaca coast to southeast Guerrero, between 10 and 20
inches of rain with isolated totals near 30 inches can be
expected through Thu. Swells associated with John are forecast to
continue to affect the coast of southern Mexico during the next
couple of days, with the potential for dangerous surf and rip
currents much of the week. Please see local statements for more
information.

Please read the latest HIGH SEAS FORECAST issued by the National
Hurricane Center at website -
https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest
John NHC Forecast/Advisory and Public Advisory at
www.hurricanes.gov for more details.

A Central American Gyre will generate periods of excessive
rainfall over southern Mexico and Central America for the
remainder of the week, as well as the adjacent western Caribbean
and eastern Pacific waters between 80W and 95W. This scenario,
combined with daytime heating and orographic lifting, could
produce dangerous flash flooding and mudslides across the area.
Furthermore, strong to near gale force winds, rough seas and
heavy thunderstorms are forecast to affect the offshore waters
between Costa Rica and El Salvador through the end of the week.
Please follow the forecasts from your local weather offices for
more detailed information.

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

The monsoon trough axis extends from 14N108W to 14N121W to
10N130W to 12N140W. Aside from convection related to John and
the Central American Gyre, scattered moderate convection is seen
within 120 nm south of the trough between 108W and 112W and
within 30 nm of the trough between 126W and 129W.

...OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Please refer to the Special Features section above for
information on Tropical Storm John and on the Central American
Gyre (CAG).

A high pressure ridge extends southeastward from a 1023 mb high
center that is located well northwest of the area to near
25N125W. The gradient between it and relatively lower pressure
in northwest Mexico is allowing for generally gentle to moderate
northwest to north winds to exist over the offshore waters. Light
to gentle northwest winds are over the Gulf of California. Seas
are 1 to 3 ft over the Gulf, except for higher seas of 3 to 5 ft
at the entrance to the Gulf. South to southwest fresh to strong
winds with embedded patches of near gale winds on the outer
periphery of Tropical Storm John were highlighted by a couple of
ASCAT satellite data passes. These winds reach as far south of
09N and north to near 16N. Seas with these winds are 8 to 11 ft,
except 9 to 14 ft within the patches of winds to near gale.

For the forecast in addition to those conditions described above
for Hurricane John, high pressure will maintain generally gentle
to moderate northwest to north winds over the offshore waters.
Winds are forecast to increase to fresh speeds over most of the
offshore waters starting Wed, with little change expected going
into the early part of the upcoming weekend.

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

Please refer to the Special Features section above for
information on the Central American Gyre (CAG).

Moderate to fresh southwest winds are over the offshore waters
of Central America north of Guatemala while gentle to moderate
winds are elsewhere. Seas are 6 to 9 ft in west swell over
the offshore waters of Guatemala. Seas are 4 to 7 ft over the
remainder of the offshore waters.  Moderate to strong convection
is occurring from 05N to 10N between 81W and 90W, including in
the waters off the coasts of Panama and Costa Rica. Strong winds
and rough seas will occur near convection.

For the forecast, moderate to fresh southwest winds will
continue in the wake of major Hurricane John off the coast of
Central America through north of Guatemala through Wed night.
West to northwest swell will propagate generally eastward in the
wake of John, through the waters of Guatemala tonight, expanding
farther east toward El Salvador on Tue, and toward Nicaragua Wed.
Periods of strong convection will also occur over most of the
Central America offshore waters through at least through Wed.

...REMAINDER OF THE AREA...

The gradient related to high pressure ridging over the area is
supporting moderate to fresh northeast winds west of about 130W,
and gentle to moderate winds east of 130W. Seas are 6 to 8 ft
with these winds. Elsewhere, fresh to locally strong southwest
winds continue south of the monsoon trough east of 125W and
north of 09N.

For the forecast, moderate to fresh south to southwest winds will
continue south of the monsoon trough through late in the week.
Fresh to strong southwest winds will generally occur from 09N to
16N and east of 115W through Wed, with stronger southwest winds
to near gale force expected east of 102W through at least Fri.
Rough seas will accompany these gusty winds. Looking ahead,
tropical cyclone formation is not expected for the next 7 days.

$$
Aguirre