Thursday, August 17, 2023

Hurricane Hilary



 

000

WTPZ34 KNHC 172055

TCPEP4


BULLETIN

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

----------------------------------------------

LOCATION...16.1N 108.9W

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

the weekend.


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

(445 km).


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

early Saturday.


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 PM MDT.

Next complete advisory at 900 PM MDT.


$$

Forecaster Pasch


000

WTPZ44 KNHC 172056

TCDEP4


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

this advisory.


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.



KEY MESSAGES:


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


$$

Forecaster Pasch


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