WTPZ34 KNHC 172055
Hurricane Hilary Advisory Number 6
NWS National Hurricane Center Miami FL EP092023
300 PM MDT Thu Aug 17 2023
...HILARY APPROACHING MAJOR HURRICANE STATUS...
SUMMARY OF 300 PM MDT...2100 UTC...INFORMATION
ABOUT 475 MI...765 KM S OF CABO SAN LUCAS MEXICO
MAXIMUM SUSTAINED WINDS...110 MPH...175 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...960 MB...28.35 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
The government of Mexico has extended the Tropical Storm Watch
northward on the west coast of the Baja California peninsula
to Punta Abreojos, and northward on the east coast of the Baja
California peninsula to Loreto.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Tropical Storm Warning is in effect for...
* Baja California Sur Mexico from Cabo San Lazaro southward
* Baja California Sur Mexico from Los Barriles southward
A Tropical Storm Watch is in effect for...
* North of Cabo San Lazaro to Punta Abreojos
* North of Los Barriles to Loreto
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 tonight and Friday.
For storm information specific to your area, please monitor
products issued by your national meteorological service.
DISCUSSION AND OUTLOOK
At 300 PM MDT (2100 UTC), the center of Hurricane Hilary was located
near latitude 16.1 North, longitude 108.9 West. Hilary is moving
toward the west-northwest near 14 mph (22 km/h), and this general
motion is expected to continue through tonight. A turn toward the
northwest is expected Friday morning, followed by a turn toward the
north-northwest and north on Saturday. On the forecast track, the
center of Hilary will approach the Baja California peninsula over
Maximum sustained winds have increased to near 110 mph (175 km/h)
with higher gusts. Additional rapid strengthening is forecast
during the next day or so, and Hilary is likely to become a major
hurricane later today.
Hurricane-force winds extend outward up to 60 miles (95 km) from the
center and tropical-storm-force winds extend outward up to 275 miles
The estimated minimum central pressure is 960 mb (28.35 inches).
HAZARDS AFFECTING LAND
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 from Friday through early next week,
peaking on Sunday and Monday. Rainfall amounts of 2 to 4 inches,
with isolated amounts in excess of 8 inches, will be possible across
portions of southern California and southern Nevada.
WIND: Tropical storm conditions are expected within the warning
area by late Friday, and are possible within the watch area by
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 intermediate advisory at 600 PM MDT.
Next complete advisory at 900 PM MDT.
WTPZ44 KNHC 172056
Hurricane Hilary Discussion Number 6
NWS National Hurricane Center Miami FL EP092023
300 PM MDT Thu Aug 17 2023
Hilary has an impressive appearance on satellite imagery. The
eye, which is becoming better defined, is surrounded by very cold
cloud tops in the CDO. There are numerous convective banding
features, especially over the eastern semicircle of the
circulation. Upper-level outflow is well-defined over all but the
northwestern quadrant of the circulation. Recent objective Dvorak
T-numbers support an intensity of about 95 kt, which is used for
The hurricane continues to move on a west-northwestward track with
an initial motion estimate of 300/13 kt. Global models indicate
that a mid-tropospheric ridge currently situated to the north of
Hilary will shift eastward over the next few days while a cutoff
low remains near the California coast. This should result in a
steering pattern that will cause the system to gradually turn
toward the northwest, north-northwest, and north with increasing
forward speed during the next 72 hours. The official forecast
track has not changed much from the past few advisory packages, and
is a blend of the simple and corrected dynamical model consensus
solutions. Since the forecast track is roughly paralleling the
coastline north of the central Baja peninsula to the California
border, it nearly impossible to know at this point if the
center will remain just offshore or move over the peninsula before
reaching the southwestern United States.
Hilary is over very warm waters, near 30 deg C, with extremely
low vertical wind shear and a moist mid- to low-level atmospheric
environment. Therefore additional intensification is highly
likely for the next day or so. The various SHIPS rapid
intensification (RI) indices continue to show high probabilities of
RI during the next day or so. The most likely indicated intensity
increase is around 25 kt over the next 24 hours, which is also shown
in the NHC forecast. Later in the forecast period, cooler waters
and land interaction should result in some weakening. The official
wind speed forecast remain near or above latest HCCA guidance. The
surface circulation is likely to be dissipated by day 5, but a day 5
forecast point (as a remnant low) is still provided to maintain a
forecast track over the southwestern United States.
1. Heavy rainfall associated with Hilary may produce areas of flash
flooding and result in landslides over portions of Baja California
Peninsula from late Friday into late Sunday. Rainfall impacts from
Hilary within the Southwestern United States are expected to peak
this weekend into Monday. Flash, urban, and arroyo flooding is
possible with the potential for significant impacts.
2. The threat of hurricane-force wind impacts is increasing along
the west-central coast of the Baja California Peninsula and
hurricane watches could be issued for a portion of that area
tonight. Tropical storm conditions are expected to spread across
the southern portion of the Baja California Peninsula by late Friday
where a Tropical Storm Warning is in effect.
3. The threat of significant wind impacts continues to increase for
the northern portions of the Baja California Peninsula and the
Southwestern United States, especially in areas of mountainous
terrain. Although it is too soon to determine the location and
magnitude of these impacts, interests in these areas should monitor
the progress of Hilary and updates to the forecast. Watches could
be issued for portions of this area on Friday.
4. Large swells from Hilary will spread northward along the coast
of southwestern Mexico and the Baja California Peninsula. These
swells will reach the Gulf of California and northern portions of
the Baja California Peninsula later this weekend.
FORECAST POSITIONS AND MAX WINDS
INIT 17/2100Z 16.1N 108.9W 95 KT 110 MPH
12H 18/0600Z 17.0N 110.4W 110 KT 125 MPH
24H 18/1800Z 18.4N 112.0W 120 KT 140 MPH
36H 19/0600Z 20.3N 113.0W 120 KT 140 MPH
48H 19/1800Z 22.4N 113.8W 115 KT 130 MPH
60H 20/0600Z 25.0N 114.5W 105 KT 120 MPH
72H 20/1800Z 28.5N 115.4W 85 KT 100 MPH
96H 21/1800Z 35.4N 118.4W 30 KT 35 MPH...INLAND
120H 22/1800Z 43.0N 120.0W 20 KT 25 MPH...POST-TROP/INLAND