516
AXPZ20 KNHC 252157
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Wed Sep 25 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 1800 UTC surface analysis and satellite imagery through
2130 UTC.

...SPECIAL FEATURES...

Tropical Storm John is centered near 16.8N 101.5W at 25/2100
UTC, moving north at 3 kt. Estimated minimum central pressure is
996 mb. Maximum sustained wind speed is 45 kt with gusts to 55
kt. Seas of 12 ft or greater are occurring within 240 NM in the
SE quadrant and 210 NM in the SW quadrant with peak seas near 16
ft. Convection is becoming increasingly organized around the
center of John, with strong convection occurring within 75 NM to
the east, south and north of the center, and within 150 NM to
the west. John is forecast to strengthen as it approaches the
coast of southern Mexico on Thursday. John will move to 17.1N
101.5W Thu morning, strengthen to a hurricane near 17.5N 101.5W
Thu afternoon, move inland and weaken to a tropical storm near
18.0N 101.6W Fri morning, move inland and weaken to a tropical
depression near 18.2N 102.1W Fri afternoon, and dissipate Sat
morning. Through Friday, Tropical Storm John is expected to
produce additional rainfall amounts of 10 to 20 inches with
isolated totals around 30 inches across portions of the Mexican
States of Guerrero, Oaxaca and Michoacan. A dangerous storm surge
is expected to produce coastal flooding near and to the east of
where the center makes landfall. Near the coast, the surge will
be accompanied by large and destructive waves. 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 continue to produce 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 Guatemala 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 13N110W to beyond 09N140W.
Aside from the convection related to Tropical Storm John and the
Central American Gyre, scattered moderate to locally strong
convection is occurring from 11N to 14N between 112W and 118W,
and from 09N to 11N between 129W and 140W.

...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 1005mb low pressure is centered near 34N114W and troughing
extends through the Gulf of California toward Tropical Storm
John. This pattern supports moderate to fresh NW winds and seas
of 4-7 ft across much of the Mexico offshore waters. Light to
gentle breezes and seas of 1-3 ft prevail in the Gulf of
California. Farther south, south of 18N and east of 105W, strong
to near gale force winds are occurring along the periphery of
Tropical Storm John, as confirmed by a recent scatterometer
pass. A recent altimeter pass portrayed seas of 9 to 15 ft
associated with these winds.

For the forecast away from the direct impacts from Tropical Storm
John, strong to near gale force winds will continue south of 18N
and east of 106W into early Fri. Winds will slowly diminish
below strong speeds Fri night, diminishing further on Sat. Rough
to very rough seas will accompany these winds through late Fri
before slowly subsiding Sat into Sun. Elsewhere, mostly fresh
northwest winds and moderate to locally rough seas will occur
across the remainder of the Mexican offshore waters through Sat,
with the exception of the Gulf of California, where winds will
remain light to gentle.

...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 SW winds are occurring over the coastal waters
from Guatemala through Nicaragua, and seas of 6-10 ft are noted
in this area. Gentle to moderate S to SW winds and seas of 4-7 ft
prevail elsewhere. Scattered moderate to locally strong
convection is noted north of 11N between 88W and 94W, with
similar convection noted north of 04N and east of 86W toward
Panama and Colombia. Strong winds and rough seas will occur near
convection.

For the forecast, moderate to fresh SW winds will continue
across the offshore waters of Nicaragua tonight, and persist
across the waters of El Salvador and Guatemala through Fri.
Moderate to rough seas will accompany these winds, with seas
slowly subsiding this weekend. Elsewhere, gentle to moderate SW
winds will continue into early next week. Scattered to numerous
showers and thunderstorms will continue over most of the offshore
waters through the rest of the week.

...REMAINDER OF THE AREA...

A recent scatterometer pass revealed strong to near gale force
winds along the periphery of Tropical Storm John, generally
north of 10N and east of 109W. Seas of 9 to 13 ft are likely
occurring in this region. Moderate to locally fresh SW winds are
noted south of the monsoon trough east of 120W and north of 09N.
Elsewhere, gentle to moderate N to NE winds prevail north of the
monsoon trough with seas of 4-7 ft.

For the forecast, strong to near gale force winds will continue
north of 09N and east of 114W through Fri before winds slowly
diminish through Sat. Rough to locally very rough seas will
accompany these winds, with seas slowly subsiding this weekend
into early next week. Elsewhere, a building NW swell will lead
to seas of 8 to 9 ft north of 22N and west of 126W tonight
through Thu.

$$
ADAMS