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BULLETIN
Hurricane Hilary Advisory Number   8
NWS National Hurricane Center Miami FL       EP092023
300 AM MDT Fri Aug 18 2023
 
...HILARY IS A LARGE AND POWERFUL CATEGORY 4 HURRICANE...
...SIGNIFICANT FLOODING IMPACTS POSSIBLE ACROSS PORTIONS OF THE
BAJA CALIFORNIA PENINSULA AND THE SOUTHWESTERN UNITED STATES EARLY
NEXT WEEK...
 
 
SUMMARY OF 300 AM MDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...17.2N 110.8W
ABOUT 110 MI...180 KM S OF SOCORRO ISLAND
ABOUT 400 MI...640 KM S OF CABO SAN LUCAS MEXICO
MAXIMUM SUSTAINED WINDS...145 MPH...230 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...942 MB...27.82 INCHES
 
 
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:
 
The government of Mexico has extended the Tropical Storm Warning on
the west side of the Baja California peninsula to Punta Abreojos and
on the east side of the Baja California peninsula to Loreto.
 
The Hurricane Watch on the west side of the Baja California
peninsula has been extended northward to San Jose de Las Palmas.
 
The Tropical Storm Watch on the east side of the Baja California
peninsula has been extended northward to Bahia de Los Angeles.  A
Tropical Storm Watch has also been issued for mainland Mexico from
Huatabampito to Bahia Kino.
 
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
 
A Hurricane Watch is in effect for...
* Baja California peninsula north of Punta Abreojos to San Jose de
Las Palmas
 
A Tropical Storm Warning is in effect for...
* Baja California peninsula from Punta Abreojos southward
* Baja California peninsula from Loreto southward
 
A Tropical Storm Watch is in effect for...
* Baja California peninsula north of Loreto to Bahia de Los Angeles
* Mainland Mexico from Huatabampito to Bahia Kino
 
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 elsewhere on the Baja California peninsula, along the
coast of northwestern mainland Mexico, and the southwestern United
States coastline should closely monitor the progress of Hilary.
Additional watches or warnings will likely be required for portions
of these areas later today.
 
For storm information specific to your area, please monitor
products issued by your national meteorological service.
 
 
DISCUSSION AND OUTLOOK
----------------------
At 300 AM MDT (0900 UTC), the center of Hurricane Hilary was located
near latitude 17.2 North, longitude 110.8 West.  Hilary is moving
toward the west-northwest near 13 mph (20 km/h).  A turn toward the
northwest and north-northwest is expected today and 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 have increased to near 145 mph (230 km/h)
with higher gusts.  Hilary is a category 4 hurricane on the
Saffir-Simpson Hurricane Wind Scale.  Fluctuations in intensity are
likely over the next day or so.  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 Sunday
afternoon 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 290 miles
(465 km).  Over the past few hours, an automated Mexican navy
station on Socorro Island measured a sustained wind of 38 mph (61
km/h) and a wind gust to 64 mph (102 km/h).
 
The estimated minimum central pressure is 942 mb (27.82 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 flooding, locally significant, will be possible.
 
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, which would lead to significant and rare
impacts.  Elsewhere across portions of the Western United States,
rainfall totals of 1 to 3 inches are expected.
 
WIND:  Hurricane conditions are possible within the hurricane watch
area by Saturday night or Sunday morning, with tropical storm
conditions possible by Saturday.  Tropical storm conditions are
expected within the warning area by late today, and are possible
within the watch area by early Saturday.
 
STORM SURGE:  A storm surge could 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 and the Baja California peninsula 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
-------------
Next intermediate advisory at 600 AM MDT.
Next complete advisory at 900 AM MDT.
 
$$
Forecaster Berg
 
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