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BULLETIN
Hurricane Hilary Advisory Number  15
NWS National Hurricane Center Miami FL       EP092023
900 PM MDT Sat Aug 19 2023
 
...HEAVY RAINS CONTINUE TO SPREAD NORTHWARD OVER THE BAJA PENINSULA
AND THE SOUTHWESTERN UNITED STATES...
...CATASTROPHIC AND LIFE-THREATENING FLOODING LIKELY...
 
 
SUMMARY OF 900 PM MDT...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...25.3N 114.6W
ABOUT 175 MI...280 KM S OF PUNTA EUGENIA MEXICO
ABOUT 535 MI...855 KM SSE OF SAN DIEGO CALIFORNIA
MAXIMUM SUSTAINED WINDS...90 MPH...150 KM/H
PRESENT MOVEMENT...NNW OR 345 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...968 MB...28.59 INCHES
 
 
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:
 
The government of Mexico has discontinued the Tropical Storm
Warning on the east coast of the Baja California Peninsula south of
Los Barilles, and on the west coast of the Baja California
Peninsula south of Todos Santos,
 
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
 
A Hurricane Warning is in effect for...
* Baja California peninsula from Punta Abreojos to Cabo San Quintin
 
A Hurricane Watch is in effect for...
* Baja California peninsula north of Cabo San Quintin to Ensenada
 
A Tropical Storm Warning is in effect for...
* Baja California peninsula from Punta Abreojos to Todos Santos
* Baja California peninsula east coast from Los Barilles northward
* Baja California peninsula north of Cabo San Quintin to the
California/Mexico border
* Mainland Mexico north of Guaymas
* California/Mexico border to Point Mugu
* Catalina Island
 
A Tropical Storm Watch is in effect for...
* Mainland Mexico from Huatabampito to Guaymas
 
A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area.
 
A Hurricane Watch means that hurricane conditions are possible
within the watch area, in this case within the next 12 to 24 hours.
 
A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning.
 
A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area.
 
Interests elsewhere in the southwestern U.S. should monitor the
progress of Hilary.
 
For storm information specific to your area in the United
States, including possible inland watches and warnings, please
monitor products issued by your local National Weather Service
forecast office. For storm information specific to your area
outside of the United States, please monitor products issued by
your national meteorological service.
 
 
DISCUSSION AND OUTLOOK
----------------------
At 900 PM MDT (0300 UTC), the center of Hurricane Hilary was located
near latitude 25.3 North, longitude 114.6 West. Hilary is moving
toward the north-northwest near 18 mph (30 km/h).  The hurricane is
expected to accelerate as it moves north-northwestward to northward
during the next day or two. On the forecast track, the center of
Hilary will move close to the west-central coast of the Baja
California Peninsula tonight and Sunday morning then move across
southern California Sunday afternoon.
 
Maximum sustained winds are near 90 mph (150 km/h) with higher
gusts. Continued weakening is expected, but Hilary is likely to 
still be a hurricane when it approaches the west coast of the Baja 
California Peninsula later tonight. Hilary is expected to weaken to 
a tropical storm before it reaches southern California.
 
Hurricane-force winds extend outward up to 45 miles (75 km) from the
center and tropical-storm-force winds extend outward up to 265 miles
(425 km).  A sustained wind of 58 mph (93 km/h) and a gust of
69 mph (111 km/h) were reported at Loreto, Mexico, within the past 
couple of hours.
 
The estimated minimum central pressure is 968 mb (28.59 inches).
 
 
HAZARDS AFFECTING LAND
----------------------
Key messages for Hilary can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDEP4 and WMO header WTPZ44 KNHC
and on the web at hurricanes.gov/text/MIATCDEP4.shtml.
 
RAINFALL:  Hilary is expected to produce storm total rainfall 
amounts of 3 to 6 inches, with isolated maximum amounts up to 10 
inches, across portions of the northern Baja California Peninsula 
through Sunday night. Flash and urban flooding, locally 
catastrophic, is expected, especially in the northern portions of 
the peninsula.

Heavy rainfall in association with Hilary is expected across the 
Southwestern United States, peaking during the next day or so. 
Rainfall amounts of 3 to 6 inches, with isolated amounts of 10 
inches, are expected across portions of southern California and 
southern Nevada. Dangerous to catastrophic flooding is expected.  
Elsewhere across portions of the Western United States, rainfall 
totals of 1 to 3 inches are expected, resulting in localized 
significant flash flooding.
 
WIND:  Hurricane conditions are expected within the hurricane
warning area tonight and early Sunday and are possible within the
hurricane watch area on Sunday.  Tropical storm conditions are 
occurring within the southern portion of the tropical storm warning 
area and will spread northward tonight and Sunday.  Tropical storm 
conditions are possible within the tropical storm watch area through 
early Sunday.  Tropical storm conditions are expected to begin in 
southern California on Sunday.
 
Winds could be particularly strong and gusty in and near areas of
elevated terrain.  Higher gusts are expected well inland and will
persist even after the system becomes post-tropical.
 
STORM SURGE:  A dangerous storm surge is likely to produce coastal
flooding along the western Baja California peninsula of Mexico near
where the center passes the coast in areas of onshore winds, or
east of the center if Hilary makes landfall. The surge will be
accompanied by large and destructive waves.  Coastal flooding is
possible along the northern coast of the Gulf of California Sunday
through early Monday.
 
TORNADOES: A tornado or two may occur Sunday from mid-morning
through the evening over parts of the lower Colorado River Valley,
Mojave Desert, and Imperial Valley regions.
 
SURF:  Large swells generated by Hilary will affect portions of the
Baja California Peninsula and southern California over the next
couple of days.  These swells are likely to cause life-threatening
surf and rip current conditions.  Please consult products from your
local weather office.
 
 
NEXT ADVISORY
-------------
Next intermediate advisory at 1200 AM MDT.
Next complete advisory at 300 AM MDT.
 
$$
Forecaster Brown
 
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