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BULLETIN
Hurricane Hilary Intermediate Advisory Number 10A
NWS National Hurricane Center Miami FL       EP092023
600 PM MDT Fri Aug 18 2023
 
...OUTER BANDS FROM HILARY SPREADING ONSHORE OVER THE SOUTHERN 
PORTIONS OF BAJA CALIFORNIA...
...LIFE-THREATENING AND POTENTIALLY CATASTROPHIC FLOODING LIKELY
OVER MUCH OF BAJA CALIFORNIA AND THE SOUTHWESTERN UNITED STATES 
THIS WEEKEND AND EARLY NEXT WEEK...
  
SUMMARY OF 600 PM MDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...19.1N 112.4W
ABOUT 95 MI...150 KM WNW OF SOCORRO ISLAND
ABOUT 310 MI...495 KM SSW OF CABO SAN LUCAS MEXICO
MAXIMUM SUSTAINED WINDS...130 MPH...215 KM/H
PRESENT MOVEMENT...NW OR 325 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...948 MB...28.00 INCHES
 
 
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:
 
None
 
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 southward
* Baja California peninsula entire east coast
* Mainland Mexico north of Guaymas
 
A Tropical Storm Watch is in effect for...
* Mainland Mexico from Huatabampito to Guaymas
* Baja California north of Ensenada to the California/Mexico border
* California/Mexico border to Point Mugu
* Catalina Island
 
A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area.  A warning is typically issued
36 hours before the anticipated first occurrence of
tropical-storm-force winds, conditions that make outside
preparations difficult or dangerous.  Preparations to protect life
and property should be rushed to completion.
 
A Hurricane Watch means that hurricane conditions are possible
within the watch area.  A watch is typically issued 48 hours
before the anticipated first occurrence of tropical-storm-force
winds, conditions that make outside preparations difficult or
dangerous.
 
A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area within 36 hours.
 
A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.
 
Interests 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 600 PM MDT (0000 UTC), the center of Hurricane Hilary was located
near latitude 19.1 North, longitude 112.4 West. Hilary is moving
toward the northwest near 12 mph (19 km/h). A turn toward the
north-northwest is expected tonight, followed by a faster motion
toward the north Saturday night and Sunday.  On the forecast track,
the center of Hilary will move close to the west coast of the Baja
California peninsula over the weekend and reach southern California
by Sunday night.
 
Maximum sustained winds are near 130 mph (215 km/h) with higher
gusts.  Hilary is a category 4 hurricane on the Saffir-Simpson
Hurricane Wind Scale. Fluctuations in intensity are likely through
tonight.  Weakening is expected to begin by Saturday, but Hilary
will still be a hurricane when it approaches the west coast of the
Baja California peninsula Saturday night and Sunday.  Hilary is
expected to weaken to a tropical storm by late Sunday before it
reaches southern California.
 
Hurricane-force winds extend outward up to 50 miles (85 km) from
the center and tropical-storm-force winds extend outward up to 275
miles (445 km). An automated weather station on Socorro Island has 
measured peak sustained winds of 47 mph (76 km/h) with a gust to 
79 mph (128 km/h) today.
 
The estimated minimum central pressure is 948 mb (28.00 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 rainfall amounts of 3 to 6
inches, with isolated maximum amounts up to 10 inches, across
portions of the Baja California Peninsula through Sunday night.
Flash and urban flooding, locally catastrophic, will be possible,
especially in the northern portions of the peninsula.
 
Heavy rainfall in association with Hilary is expected to impact the
Southwestern United States through next Wednesday, peaking on Sunday
and Monday. 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 locally catastrophic flooding will
be possible.  Elsewhere across portions of the Western United
States, rainfall totals of 1 to 3 inches are expected, resulting in
localized flash flooding.
 
WIND:  Hurricane conditions are expected within the hurricane
warning area beginning Saturday night and are possible within the
hurricane watch by early Sunday. Tropical storm conditions are
expected within the warning area tonight, and are possible
within the watch area in Mexico on Saturday and Sunday and in
southern California beginning late Sunday.
 
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.
 
SURF:  Large swells generated by Hilary will affect portions of the
coast of southwestern Mexico, the Baja California peninsula, and
south California over the next few days.  These swells are likely
to cause life-threatening surf and rip current conditions.  Please
consult products from your local weather office.
 
 
NEXT ADVISORY
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Next complete advisory at 900 PM MDT.
 
$$
Forecaster Brown/Kelly
 
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