Major Hurricane Hilary | Cat 4 Peak 145mph 939mb | 125mph 947mb

[StretchCT]

Wow, Hilary reaches hurricane status on the 4th advisory.

 

 

Hilary skipped the protocol of being a depression and started off as a TS on Wednesday at 15UTC.  Not even 24 hrs later its a hurricane.  It is forecast to peak at 130mph. It's also headed to either Baja or Cali.

Tropical Storm Hilary Advisory Number   1
NWS National Hurricane Center Miami FL       EP092023
1000 AM CDT Wed Aug 16 2023
 
...TROPICAL STORM HILARY FORMS...
...EXPECTED TO STRENGTHEN...
 
 
SUMMARY OF 1000 AM CDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...12.4N 102.6W
ABOUT 470 MI...755 KM SSE OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES

The water in the E Pac is similar to the water in the GOM/W ATL, perhaps a degree or two cooler.

 

Edited August 19, 2023 by StretchCT

[StretchCT]

Not the prettiest but will become powerful

 

[StretchCT]

California just in the 40-50% chance of TS force winds.  Weird

 

These include remnants.  Comparing frequency in other areas. Expanded CA to 120 miles to get at least 10 storms.

10 tropical storms/depressions have been near Southern CA.  Gray is extratropical, blue is depression green TS 

Compared to New Haven CT with 104

 

San Juan with 143

 

OBX with 263

 

Edited August 17, 2023 by StretchCT

[telejunkie]

1 hour ago, StretchCT said:

California just in the 40-50% chance of TS force winds.  Weird

 

These include remnants.  Comparing frequency in other areas. Expanded CA to 120 miles to get at least 10 storms.

10 tropical storms/depressions have been near Southern CA.  Gray is extratropical, blue is depression green TS 

Compared to New Haven CT with 104

 

San Juan with 143

 

OBX with 263

 

That's a cool feature! What site is that? 

Strong threat for flash flooding issues too in the desert

[StretchCT]

[StretchCT]

2 hours ago, telejunkie said:

That's a cool feature! What site is that? 

https://coast.noaa.gov/hurricanes/#map=4/32/-80

[StretchCT]

75mph this morning, now its 120mph.  Forecast to 140mph

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

 

Edited August 18, 2023 by StretchCT

[Mainiac]

Looks like it’s trending back a bit east in the latest NHC cone update, although there are still a few outlier models having it make landfall as a cat 1 in Santa Barbara. 👀

 

Definitely going to be a major rain event and probably historic for some locales.

[StretchCT]

First ever tropical storm watch for the west coast. Though the only tropical storm to hit is 1939. 

Edited August 18, 2023 by StretchCT

[Sentinel]

5 minutes ago, StretchCT said:

First ever tropical storm watch for the west coast. 

This outflow is some of the most spectacular I have seen in the Eastern Pacific. 

[StretchCT]

[StretchCT]

Good discussion and confirmation it's the first tropical storm watch for CA.  Recon going in later, double eyewall on microwave, 15-20nm eye, extra soundings going up, winds 250mi from center. 

Spoiler

Hurricane Hilary Discussion Number   9
NWS National Hurricane Center Miami FL       EP092023
900 AM MDT Fri Aug 18 2023

After an impressive 70-kt increase in winds over the past 24 hours,
Hilary's intensity has leveled off.  Satellite data indicate that
Hilary remains an impressive major hurricane with a 15-20 n mi
diameter eye and symmetric convective cloud pattern surrounding that
feature.  A blend of the latest satellite intensity estimates
support holding the initial intensity steady at 125 kt.  Microwave
data is showing some signs of a double eyewall structure, which is
quite common in strong hurricanes like Hilary.  Hilary is quite
large with its tropical-storm-force winds extending up to 250 n mi
from the center. The Air Force Hurricane Hunters are scheduled to
investigate the hurricane later today, and the data they collect
will provide a better assessment of the system's strength and
structure.

Hilary has turned to the northwest with the initial motion estimated 
to be 305/9 kt.  A general north-northwest to north motion with a 
steady increase in forward speed is expected later today and through 
the weekend as the system is steered by the flow between a strong 
subtropical ridge over the south-central U.S. and a mid- to 
upper-level low off the central California coast.  This pattern 
should take the core of Hilary near the central Baja California 
Peninsula coast Saturday night and then inland over southern 
California Sunday night.  The models are in fairly good agreement, 
and little change was made to the previous track forecast.  It 
should be noted that strong winds and heavy rains will occur well 
ahead of the center.

Fluctuations in the hurricane's strength are expected today, but
Hilary is expected to begin weakening late tonight as it moves over
progressively cooler SSTs and into an environment of increasing
shear and drier air.  The NHC intensity forecast follows the HCCA
and IVCN models and is largely an update of the previous one.

Based on the forecast, a Tropical Storm Watch has been issued for
portions of southern California.  This is the first time NHC has
issued a watch for that region.  Supplemental soundings (weather
balloons) are being launched by much of the National Weather Service
offices across the western U.S.  This effort is highly appreciated
as the data should help provide a better assessment of the
environment and steering pattern ahead of Hilary.


KEY MESSAGES:

1. Heavy rainfall associated with Hilary could produce areas of
flash flooding and result in landslides over portions of the Baja
California Peninsula late tonight through 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 expected, with the potential for rare and dangerous
impacts.

2. Hurricane conditions are expected within portions of the
hurricane warning area along the west-central coast of the Baja
California Peninsula on Sunday and are possible in the Hurricane
Watch area.

3. Tropical storm conditions are possible on Sunday in portions of
southern California where a Tropical Storm Watch has been issued.

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  18/1500Z 17.9N 111.4W  125 KT 145 MPH
 12H  19/0000Z 19.2N 112.5W  130 KT 150 MPH
 24H  19/1200Z 21.3N 113.6W  115 KT 130 MPH
 36H  20/0000Z 23.7N 114.4W  100 KT 115 MPH
 48H  20/1200Z 26.8N 115.2W   85 KT 100 MPH
 60H  21/0000Z 30.4N 116.4W   65 KT  75 MPH
 72H  21/1200Z 35.2N 117.4W   45 KT  50 MPH...INLAND
 96H  22/1200Z...DISSIPATED

$$
Forecaster Cangialosi

 

[rmo09001]

This has been a fun follow and an unexpected twist to what's been an unusual summer in SoCal. I'll be embracing the rain, which is a massive bonus in August. 

[telejunkie]

51 minutes ago, rmo09001 said:

This has been a fun follow and an unexpected twist to what's been an unusual summer in SoCal. I'll be embracing the rain, which is a massive bonus in August. 

Gotta imagine Temecula vineyards are scrambling to harvest grapes right now....big rains around harvest are no bueno. 1" of rain in a day and skins will definitely be splitting...

Most recent rainfall map:

Flash Flood potential:

Edited August 18, 2023 by telejunkie

[StretchCT]

Recon with one pass through didn't find Cat 4 conditions.  948mb with top flight wind 130mph and top sfmr winds 107mph.  Drops found 82 and 97mph at surface with 144mph as the max at 850mb level.  Not sure what they do with this info but it doesn't seem to be in the 930s anymore for sure.  Trying to find a max wind on one pass isn't terribly reliable either.  

Spoiler

Product: Air Force Vortex Message (URPN12 KNHC)
Corrected: This observation corrected a previous observation.
Transmitted: 18th day of the month at 18:37Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF96-5300
Storm Name: Hilary
Storm Number & Year: 09 in 2023 (flight in the Northeast Pacific basin)
Mission Number: 1
Observation Number: 08

A. Time of Center Fix: 18th day of the month at 18:02:30Z
B. Center Fix Coordinates: 18.16N 111.94W
B. Center Fix Location: 352 statute miles (567 km) to the SSW (202°) from Cabo San Lucas, Baja California Sur, Mexico.
C. Minimum Height at Standard Level: 2,664m (8,740ft) at 700mb
D. Minimum Sea Level Pressure: 948mb (28.00 inHg)
E. Dropsonde Surface Wind at Center: From 200° at 11kts (From the SSW at 13mph)
F. Eye Character: Closed
G. Eye Shape & Diameter: Circular with a diameter of 32 nautical miles (37 statute miles)
H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 93kts (107.0mph)
I. Location & Time of the Estimated Maximum Surface Wind Inbound: 18 nautical miles (21 statute miles) to the ENE (61°) of center fix at 17:57:00Z
J. Maximum Flight Level Wind Inbound: From 143° at 113kts (From the SE at 130.0mph)
K. Location & Time of the Maximum Flight Level Wind Inbound: 19 nautical miles (22 statute miles) to the ENE (60°) of center fix at 17:56:30Z
L. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 85kts (97.8mph)
M. Location & Time of the Estimated Maximum Surface Wind Outbound: 18 nautical miles (21 statute miles) to the NW (310°) of center fix at 18:16:00Z
N. Maximum Flight Level Wind Outbound: From 57° at 96kts (From the ENE at 110.5mph)
O. Location & Time of the Maximum Flight Level Wind Outbound: 21 nautical miles (24 statute miles) to the NW (311°) of center fix at 18:17:00Z
P. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 8°C (46°F) at a pressure alt. of 3,051m (10,010ft)
Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 18°C (64°F) at a pressure alt. of 3,048m (10,000ft)
R. Dewpoint Temp (collected at same location as temp inside eye): 8°C (46°F)
R. Sea Surface Temp (collected at same location as temp inside eye): Not Available
S. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
S. Fix Level: 700mb
T. Navigational Fix Accuracy: 0.02 nautical miles
T. Meteorological Accuracy: 0.02 nautical miles

Remarks Section:
 

Maximum Flight Level Wind: 113kts (~ 130.0mph) which was observed 19 nautical miles (22 statute miles) to the ENE (60°) from the flight level center at 17:56:30Z

 

[StretchCT]

ADT looks like it peaked too.

[Burr]

 

definitely weakening - 12 hour loop.  you can see the north west side collapsing

 

 

Edited August 19, 2023 by Burr

[Burr]

[Burr]

Headed to Vegas.  Put it all on black.

[Burr]

NWS Discussion

300 AM MDT Sat Aug 19 2023

Hilary continues to display a large and well-defined eye, surrounded by very cold convective cloud tops of -75 degrees Celsius. There has been some noticeable thinning of the convection on the western side of the circulation, which could indicate that the hurricane is beginning to pull down cooler, more stable air from the north. That said, an Air Force Reserve Hurricane Hunter aircraft measured peak 700-mb flight-level winds of 128 kt, which still supports an initial intensity of 115 kt. The plane also found that the central pressure has dropped slightly to 943 mb.

Hilary continues to move toward the north-northwest, or 335/11 kt. Southerly flow between a large mid-level high over the Central Plains and a cut-off low near the central California coast is expected to accelerate Hilary north-northwestward and then northward during the next 48 hours, with its forward motion likely reaching 25-30 kt by the time the system reaches southern California on Sunday. In fact, the track guidance has sped up again on this cycle, and the updated NHC track forecast is a little faster than the previous forecast after 24 hours. Users are reminded that the exact details of the track forecast, including where Hilary might make landfall, are of little overall importance since strong winds and heavy rainfall will extend far from the center. These hazards will also begin well in advance of the arrival of the center.

The degradation of the convection on Hilary's western side probably suggests that weakening will begin very soon. Hilary's circulation will begin moving over sea surface temperatures colder than 26 degrees Celsius later this morning, and the cooler waters and corresponding more stable air mass are likely to cause fast weakening over the next couple of days. Hilary is expected to pass near the west-central coast of the Baja California peninsula still as a hurricane tonight, but then weaken to a tropical storm by Sunday while it's moving near the northwestern coast of the peninsula. Hilary will still be producing tropical-storm-force winds when it reaches southern California on Sunday. The circulation is likely to dissipate around or soon after 48 hours, but a 60-hour forecast point is still provided for track continuity.

Edited August 19, 2023 by Burr

[MaineJay]

Lot of juice heading to places that probably aren't used to these kind of PWATs.

Word of the day is Wadi.  A dry river bed most likely in a desert, that generally only fills in rainy seasons or after the very occasional heavy rain.

[1816]

52 minutes ago, MaineJay said:

Lot of juice heading to places that probably aren't used to these kind of PWATs.

Word of the day is Wadi.  A dry river bed most likely in a desert, that generally only fills in rainy seasons or after the very occasional heavy rain.

Excuse me sir, this is America. Here we call them gulches. Or gullies. Something like that. 

[1816]

1 hour ago, MaineJay said:

Lot of juice heading to places that probably aren't used to these kind of PWATs.

Word of the day is Wadi.  A dry river bed most likely in a desert, that generally only fills in rainy seasons or after the very occasional heavy rain.

Whole Lotta gullywashers incoming. And you could be 10 miles down from the storm where theres nothing going on and it comes all of a sudden. At least that's what I remember from a documentary I saw a long time ago "city slickers"

Edited August 19, 2023 by 1816

[Burr]

[Burr]