000
AXPZ20 KNHC 190941
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 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 0600 UTC surface analysis and satellite imagery through
0900 UTC.

...SPECIAL FEATURES...

Hurricane Hilary is centered near 20.9N 113.3W at 19/0900 UTC,
moving north-northwest at 11 kt. Estimated minimum central
pressure is 943 mb. Maximum sustained wind speed is 115 kt with
gusts to 140 kt. Scattered moderate to strong convection is 
noted within 120 nm in the southeast semicircle of the hurricane.
Seas in excess of 12 ft extend to 420 nm in the southeast
semicircle and 300 nm in the northwest semicircle of 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 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 today. In the Southwestern United 
States, flash, urban, and arroyo flooding is expected, with 
dangerous and locally catastrophic impacts likely from tonight into 
Mon.

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 97W north of 04N moving west at 10 to 
15 kt. Scattered moderate convection is noted north of 10N between
93W and 99W.

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

The monsoon trough axis extends from 10N85W to 09N95W to 
11N100W, and from 13N120W to 08N140W. Scattered moderate 
convection is noted within 60 nm of the coasts of Colombia,
Panama and Costa Rica. Scattered moderate convection is also
evident from 06N to 08N between 93W and 96W.

...OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
 
Please see the Special Features section for information on 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. Fresh
to strong gap winds will pulse across the Gulf of Tehuantepec
through mid week, mainly at night. 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, moderate to fresh winds will pulse across the 
Gulf of Papagayo this morning and again on Sun. Light to gentle 
breezes and slight to moderate seas will persist elsewhere into 
Sun. Looking ahead, SW winds will increase off Costa Rica and 
western Panama Mon and Tue, then diminish through mid week as the
monsoon trough lifts northward. Elsewhere across the offshore 
forecast waters of Central and South America, gentle to moderate 
winds and moderate seas are expected through the period. 

...REMAINDER OF THE AREA...

The remnant low of former tropical cyclone Fernanda is analyzed 
west of 140W near 16N141W. Recent scatterometer and altimeter
indicated fresh to strong E winds and seas to 8 ft within 120 nm
north of the center. The scatterometer passes also captured
fresh SW winds from 08N to 12N between 110W and 120W flowing into
Hilary. A ridge dominates most of the waters north of 20N and
west of 120W, supporting gentle to moderate winds elsewhere.

For the forecast, the winds and seas associated with the low near
16N141W will diminish over the next six to twelve hours west of 
140W. SW winds will start to increase south of the monsoon trough
east of 110W Mon and Tue with building seas.

$$ 
Christensen