000
AXPZ20 KNHC 190407
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Sat Aug 19 2023

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 0000 UTC surface analysis and satellite imagery through
0330 UTC.

...SPECIAL FEATURES...

Major Hurricane Hilary is centered near 19.7N 112.7W at 19/0300 
UTC, moving north-northwest at 11 kt. Estimated minimum central 
pressure is 948 mb. Maximum sustained wind speed is 115 kt with 
gusts to 140 kt. Numerous moderate to scattered strong convection
is noted within 120 nm in the southeast semicircle of the
hurricane, and within 90 nm in the northwest semicircle of the 
hurricane. Seas in excess of 12 ft extend to just under 400 nm
from the center. Hilary will maintain hurricane strength as it
moves along the coast of Baja California, before diminishing to
tropical storm strength it moves inland over the northern coast
of Baja California Norte late Sun. 

Heavy rainfall associated with Hilary will begin well in advance
of the center, from the Baja California Peninsula into the
Southwestern United States. Preparations for the impacts of flooding
from rainfall should be completed as soon as possible, as heavy rain
will increase ahead of the center on Saturday. In the Southwestern
United States, flash, urban, and arroyo flooding is expected, with
dangerous and locally catastrophic impacts likely.

Large swells generated by Hilary will affect portions of the
coast of southwestern Mexico, the Baja California peninsula, and
southern California over the next few days. These swells are likely
to cause life-threatening surf and rip current conditions.

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 
Hilary NHC Forecast/Advisory and Public Advisory at 
www.hurricanes.gov for more details.

...TROPICAL WAVES...

A tropical wave is along 96W north of 04N moving west at 10 to 15
kt. Scattered moderate convection is noted from 11N to 15N 
between 92W and 99W.

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

The monsoon trough axis extends from 10N85W to 08N95W to 12N105W,
and from 12N120W to 07N140W. Scattered moderate convection is
noted from 04N to 06N between 91W and 93W. 

...OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
 
Please see the Special Features section for information on powerful
Hurricane Hilary.

Outside of Hurricane Hilary, a small area of northerly gap winds
of 15 to 20 kt over the Gulf of Tehuantepec, associated with a
tight gradient between high pressure over the Gulf of Mexico and
lower pressure over the tropical eastern Pacific. 

For the forecast, winds and seas will gradually diminish over
Mexican offshore waters through Mon in the wake of Hilary.
Looking ahead, another area of low pressure may develop off
southern Mexico by mid week.

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

Fresh to strong northeast to east winds are pulsing across the
Papagayo this evening, with seas to 6 ft. Gentle winds are noted
elsewhere, with mostly 3 to 5 ft seas in SW swell.

For the forecast, winds will diminish slightly over the Gulf of
Papagayo. Looking ahead, SW winds will increase south of 10N
early next week with building seas. 

...REMAINDER OF THE AREA...

The remnant low of former tropical cyclone Fernanda is analyzed 
near 16N139W with a pressure of 1008 mb. Fresh to strong winds 
are still noted within 180 nm N and 60 nm S semicircles of its 
center. An earlier scatterometer pass nicely depicted these 
winds. Seas are 8-12 ft with these winds. The low is forecast to 
cross just to the west of 140W late tonight, and associated 
conditions will shift west of 140W by early Fri afternoon. A 
ridge dominates most of the waters N of 20N and W of 120W.

The pressure gradient outside Hilary and the remnant low remains
rather weak allowing for generally light to gentle northeast to 
east trade winds. Moderate to fresh winds are south of the 
monsoon trough roughly between 104W-121W due to the large 
circulation of Hilary. Elsewhere, seas are generally 4-7 ft in 
mixed swell. 

$$
Christensen