EPAC: OTIS - Aftermath - Discussion

[Sciencerocks]

[cycloneye]

BULLETIN
Tropical Storm Otis Advisory Number 6
NWS National Hurricane Center Miami FL EP182023
400 PM CDT Mon Oct 23 2023

...TROPICAL STORM WARNING AND HURRICANE WATCH ISSUED FOR PORTIONS
OF SOUTHERN MEXICO...


SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...13.1N 97.6W
ABOUT 305 MI...490 KM SSE OF ACAPULCO MEXICO
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...NNW OR 345 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

The government of Mexico has issued a Tropical Storm Warning and a
Hurricane Watch from Lagunas de Chacahua to Tecpan de Galeana


Tropical Storm Otis Discussion Number 6
NWS National Hurricane Center Miami FL EP182023
400 PM CDT Mon Oct 23 2023

The latest satellite images indicate that Otis is becoming better
organized with a curved band wrapping about halfway around the
center. However, the low-level center is still partially exposed
due to ongoing easterly vertical wind shear. An ASCAT-C pass from
a few hours ago showed peak winds close to 40 kt on the east side
of the system, and the 18Z Dvorak estimates have increased to 3.0/45
kt. Based on all of that data, the initial intensity is increased
to 45 kt.

Otis is moving slowly north-northwestward at 6 kt in the flow
between a mid- to upper-level trough to its northwest and a ridge to
its east. The models have trended to a faster solution with the
ECMWF, CMC, and UKMET global models bringing Otis to the coast of
southern Mexico on Wednesday. The GFS, however, remains an outlier
and keeps Otis weaker and offshore. The NHC track forecast leans on
the ECMWF/UKMET/CMC solutions and is a little faster than the
previous one.

Although Otis is expected to remain in a moderate wind shear
environment, abundant moisture and warm SSTs should support gradual
strengthening until Otis makes landfall. The models have
trended higher, and it now appears likely that Otis will be near
hurricane strength when it reaches the coast. Rapid weakening is
expected after Otis moves inland due to the rugged terrain in
southern and southwestern Mexico.

Based on the forecast, the government of Mexico has issued a
Tropical Storm Warning and Hurricane Watch for portions of southern
Mexico.

Key Messages:

1. Heavy rains from Otis will begin to impact areas of southwest
Mexico early this week. This rainfall will produce flash and urban
flooding, along with mudslides in areas of higher terrain.

2. Tropical storm conditions are expected and hurricane conditions
are possible beginning late Tuesday along portions of the southern
coast of Mexico, where a Tropical Storm Warning and Hurricane Watch
are in effect.


FORECAST POSITIONS AND MAX WINDS

INIT 23/2100Z 13.1N 97.6W 45 KT 50 MPH
12H 24/0600Z 13.7N 97.9W 50 KT 60 MPH
24H 24/1800Z 14.8N 98.4W 55 KT 65 MPH
36H 25/0600Z 15.6N 98.9W 60 KT 70 MPH
48H 25/1800Z 16.7N 99.8W 60 KT 70 MPH
60H 26/0600Z 17.6N 100.6W 40 KT 45 MPH...INLAND
72H 26/1800Z 18.2N 101.1W 25 KT 30 MPH...POST-TROP/INLAND
96H 27/1800Z...DISSIPATED

$$
Forecaster Cangialosi/Delgado

[cycloneye]

EP, 18, 2023102400, , BEST, 0, 133N, 978W, 45, 1000, TS

[Sciencerocks]

[cycloneye]

Tropical Storm Otis Discussion Number 7
NWS National Hurricane Center Miami FL EP182023
1000 PM CDT Mon Oct 23 2023

Otis has the appearance of a sheared tropical storm this evening,
with the center on the eastern edge of a relatively new burst of
deep convection. The overall satellite intensity estimates still
support an initial wind speed of 45 kt for this advisory. Despite
the shear, recent microwave data indicate that Otis has notable
low-level structure, with a ring observed in 37 GHz microwave data.
While this can be associated with rapid intensification, none of
the models show that intensity change occurring, seemingly due to
persistent moderate shear and some dry air in the mid-levels.
Still, it makes sense to stay on the high side of the guidance given
the structure and very warm SSTs in the path. Thus, the new NHC
forecast track is similar to the previous one, showing Otis near
hurricane strength at landfall between 36-48 hours.

Otis continues moving slowly north-northwestward at 6 kt in the flow
between a mid- to upper-level trough to its northwest and a ridge to
its east. This flow will likely cause the storm to move to the
north-northwest or northwest through landfall. While most of the
models respond by bringing Otis to the coast of southern Mexico on
Wednesday, the GFS model remains an outlier and keeps Otis weaker
and offshore. The GFS solution seems very unlikely given the
overall synoptic pattern, so the NHC track forecast will put little
weight on its solution, keeping the official forecast about the same
as the previous one, on the eastern side of the guidance envelope.

Key Messages:

1. Heavy rains from Otis will begin to impact areas of southwest
Mexico on Tuesday. This rainfall will produce flash and urban
flooding, along with mudslides in areas of higher terrain.

2. Tropical storm conditions are expected and hurricane conditions
are possible beginning late Tuesday along portions of the southern
coast of Mexico, where a Tropical Storm Warning and Hurricane Watch
remain in effect.


FORECAST POSITIONS AND MAX WINDS

INIT 24/0300Z 13.6N 97.9W 45 KT 50 MPH
12H 24/1200Z 14.4N 98.3W 50 KT 60 MPH
24H 25/0000Z 15.5N 98.9W 55 KT 65 MPH
36H 25/1200Z 16.4N 99.5W 60 KT 70 MPH
48H 26/0000Z 17.3N 100.3W 50 KT 60 MPH...INLAND
60H 26/1200Z 18.0N 101.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 27/0000Z...DISSIPATED

$$
Forecaster Blake

[Yellow Evan]

Another day, another case of RI.

[Yellow Evan]

000
WTPZ43 KNHC 240848
TCDEP3

Tropical Storm Otis Discussion Number 8
NWS National Hurricane Center Miami FL EP182023
400 AM CDT Tue Oct 24 2023

Otis has strengthened overnight. There has been a significant
increase in banding and the center is now well embedded within the
deep convection. While there has been no recent microwave imagery
to evaluate the inner core structure, a couple of earlier ASCAT
overpass indicated that the center had become embedded within the
cold cloud tops. The initial intensity has been increased to 55 kt
for this advisory, and that is in agreement with subjective Dvorak
data T-numbers of 3.5 from both SAB and TAFB.

It appears that the vertical shear over Otis has decreased as there
has been an expansion of the cirrus outflow over the eastern portion
of the storm. The shear is expected to remain light to moderate
while Otis moves over SSTs of 29-30 degrees C during the next day or
so. These conditions should allow for continued strengthening as
Otis approaches the southern coast of Mexico. The latest NHC
intensity forecast calls for Otis to become a hurricane today, and
it shows additional strengthening before Otis reaches southern
Mexico in a day or so. By 36 hours, Otis is forecast to be inland,
and rapid weakening should occur as the cyclone moves over
mountainous terrain. The NHC intensity forecast is at the high end
of the guidance in best agreement with the HWRF and HAFS-B models.
The SHIPS Rapid Intensification Index now shows about a 1 in 4
chance of rapid strengthening during the next 24 hours, which
supports being on the higher side of the guidance.

Otis is moving north-northwestward at about 7 kt. A north-northwest
motion is expected to continue during the next couple of days
between a mid- to upper-level trough to the cyclone's northwest and
a ridge to its east. The GFS has finally come onboard with this
scenario and the track guidance is much more tightly clustered than
before. The main difference is in the forward speed with the ECMWF
being on the faster side of the guidance envelope. The NHC
forecast is near a blend of the latest GFS and ECMWF models, which
is a little faster than the simple consensus aids.

Based on the updated track and intensity forecast, the government
of Mexico has issued a Hurricane Warning for a portion of the
southern coast of Mexico.


Key Messages:

1. Otis is forecast to become a hurricane before it reaches the
southern coast of Mexico late tonight or Wednesday, and hurricane
and tropical storm conditions are expected along portions of the
southern coast of Mexico where hurricane and tropical storm
warnings are in effect.

2. Heavy rains from Otis will begin to impact areas of southern and
southwestern Mexico later today. This rainfall will produce flash
and urban flooding, along with mudslides in areas of higher terrain.

3. A dangerous storm surge is expected to produce significant
coastal flooding near and to the east of where the center makes
landfall. Near the coast, the surge will be accompanied by large
and destructive waves.


FORECAST POSITIONS AND MAX WINDS

INIT 24/0900Z 14.2N 98.5W 55 KT 65 MPH
12H 24/1800Z 15.0N 99.0W 65 KT 75 MPH
24H 25/0600Z 16.1N 99.7W 75 KT 85 MPH
36H 25/1800Z 17.1N 100.3W 70 KT 80 MPH...INLAND
48H 26/0600Z 17.9N 100.9W 35 KT 40 MPH...INLAND
60H 26/1800Z 18.6N 101.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 27/0600Z...DISSIPATED

$$
Forecaster Brown

[cycloneye]

https://media.discordapp.net/attachments/619419338151034911/1166332196055953458/IMG_2253.gif?ex=654a1a80&is=6537a580&hm=34ac27e21e1be08c998fadd041835cb2ead502d228930a2b0dc9b33901bfce4f&

Another day, another case of RI.

Great that there will be recon this afternoon.

[Yellow Evan]

Likely a hurricane.

[cycloneye]

Yes, a hurricane.

TXPZ26 KNES 241215
TCSENP

A. 18E (OTIS)

B. 24/1200Z

C. 14.1N

D. 99.0W

E. THREE/GOES-E

F. T4.0/4.0

G. IR/EIR/SWIR/SSMIS

H. REMARKS...8/10 W BANDING YIELDS A DT OF 4.0. THE MET IS 3.5 BASED
ON A DEVELOPMENT TREND OVER THE PAST 24 HOURS. THE PT IS 4.0. THE FT IS
BASED ON THE DT.

I. ADDL POSITIONS

24/1101Z 14.1N 99.0W SSMIS


...COVERDALE

[cycloneye]

Tropical Storm Otis Discussion Number 9
NWS National Hurricane Center Miami FL EP182023
1000 AM CDT Tue Oct 24 2023

Satellite imagery indicates that Otis continues to become better
organized. There is very cold-topped convection with the Central
Dense Overcast surrounded by a number of convective banding
features. Upper-level outflow is well-defined over most of the
circulation. Subjective Dvorak intensity estimates range from
55 to 65 kt and the current intensity estimate is set at 60 kt
for this advisory. An Air Force Reserve Unit Hurricane Hunter
aircraft is scheduled to investigate Otis this afternoon, which
should provide a good estimate of the intensity of the tropical
cyclone.

Sea surface temperatures are very warm, around 30 deg C, and the
low-to mid-level humidities are fairly high. There is weak to
moderate south-southeasterly shear over the system, which is
located on the western periphery of an upper-tropospheric
anticyclone. Steady strengthening seems likely until Otis makes
landfall within the next day or so. Based on the current
trends, the official intensity forecast is above most of the model
guidance. The SHIPS Rapid Intensification (RI) indices show a
greater than normal probability of RI, so some further upward
adjustments to the intensity forecast are possible later today.
Otis should rapidly weaken over the mountains of Mexico after it
moves inland.

Otis continues on its north-northwestward track and the initial
motion estimate is 330/7 kt. A mostly north-northwestward
motion is expected to continue during the next couple of days while
the tropical cyclone moves between a mid- to upper-level trough to
the cyclone's northwest and a ridge to its east. On this track,
the center should cross the coastline of southern Mexico in a day
or so. The interaction of the circulation of Otis with the
mountainous terrain of Mexico could induce a slight leftward turn
as the system nears the coastline. The official track forecast is
fairly close to the previous NHC prediction and on the left side of
the model guidance suite.

Key Messages:

1. Otis is forecast to become a hurricane before it reaches the
southern coast of Mexico late tonight or Wednesday, and hurricane
and tropical storm conditions are expected along portions of the
southern coast of Mexico where hurricane and tropical storm
warnings are in effect.

2. Heavy rains from Otis will begin to impact areas of southwest
Mexico early this week. This rainfall will produce flash and urban
flooding, along with mudslides in areas of higher terrain.

3. A dangerous storm surge is expected to produce significant
coastal flooding near and to the east of where the center makes
landfall. Near the coast, the surge will be accompanied by large
and destructive waves.


FORECAST POSITIONS AND MAX WINDS

INIT 24/1500Z 14.8N 99.1W 60 KT 70 MPH
12H 25/0000Z 15.6N 99.5W 70 KT 80 MPH
24H 25/1200Z 16.6N 100.1W 80 KT 90 MPH
36H 26/0000Z 17.2N 100.6W 70 KT 80 MPH...INLAND
48H 26/1200Z 17.9N 101.3W 45 KT 50 MPH...INLAND
60H 27/0000Z 18.3N 102.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 27/1200Z...DISSIPATED

$$
Forecaster Pasch

[Sciencerocks]

 https://twitter.com/VortixWx/status/1716824003019698458

[cycloneye]

Recon will be there shortly to the eye of future hurricane Otis.

[Yellow Evan]

Eye trying to clear. Major hurricane at landfall?

[aspen]

https://media.discordapp.net/attachments/857017650042503178/1166416389779755140/IMG_2261.png?ex=654a68ea&is=6537f3ea&hm=3232361afadf8dc03237994c541b133796bc788f7294c1417f624e57a85533ee&

Eye trying to clear. Major hurricane at landfall?

Welp, there goes the streak of weak male names/Cat 4+ female names lol

[cycloneye]

BULLETIN
Hurricane Otis Intermediate Advisory Number 9A
NWS National Hurricane Center Miami FL EP182023
100 PM CDT Tue Oct 24 2023

...OTIS BECOMES A HURRICANE...
...FURTHER STRENGTHENING LIKELY UNTIL LANDFALL...


SUMMARY OF 100 PM CDT...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...14.9N 99.3W
ABOUT 145 MI...235 KM SSE OF ACAPULCO MEXICO
MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H
PRESENT MOVEMENT...NNW OR 330 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...985 MB...29.09 INCHES

[aspen]

~110 kt FL, ~100 kt SFMR. This is WAY stronger than it looks and is probably already a major.

[wxman57]

~110 kt FL, ~100 kt SFMR. This is WAY stronger than it looks and is probably already a major.

It's not stronger than it looks, it's stronger than the 18Z NHC estimate. A clearing eye often signals Cat 3.

[cycloneye]

Hurricane Otis Tropical Cyclone Update
NWS National Hurricane Center Miami FL EP182023
200 PM CDT Tue Oct 24 2023

...OTIS NEARING MAJOR HURRICANE STRENGTH...

Recent reports from an Air Force Hurricane Hunter aircraft indicate
that Otis has strengthened rapidly over the past few hours, and the
maximum sustained winds are now near 110 mph (175 km/h). A complete
advisory, including an updated intensity forecast, will be issued
by 4 PM CDT.


SUMMARY OF 200 PM CDT...1900 UTC...INFORMATION
----------------------------------------------
LOCATION...15.0N 94.4W
ABOUT 135 MI...220 KM SSE OF ACAPULCO MEXICO
MAXIMUM SUSTAINED WINDS...110 MPH...175 KM/H
PRESENT MOVEMENT...NNW OR 330 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...971 MB...28.67 INCHES

$$
Forecaster Pasch

[Astromanía]

This will take the people there by surprise