EPAC: KRISTY - Remnants - Discussion

[Kingarabian]

SAB made an erroneous 7.0 fix. They’ve downed to 6.5.


TAFB did come through with 7.0 though.

Has SAB ever had a T7.0 fix they didn’t walk back on this year? Kirk was the most clear-cut T7.0 and they still went with T6.5.

The slightly breaking W ring is probably why SAB corrected to T6.5.

Kirk was never a T7.0. Every little break counts.

It did and held it for a little bit until an ERC occurred.

[Hurricane2022]

 https://x.com/Storm_Chaser_75/status/1849559256997212419


 https://x.com/CIRA_CSU/status/1849568837538111709

[Kingarabian]

Will be nice if it can transition to annular in its last peak. Maybe the next ERC can push it to do so.

[cycloneye]

Remains at 140kt.

EP, 12, 2024102500, , BEST, 0, 144N, 1222W, 140, 926, HU

[Sciencerocks]

[WaveBreaking]

[aspen]

Will be nice if it can transition to annular in its last peak. Maybe the next ERC can push it to do so.

It doesn’t have a ton of time left in decent conditions. This EWRC will probably be the start of a final weakening trend.

[Teban54]

EWRC is well underway:

[cycloneye]

Hurricane Kristy Discussion Number 14
NWS National Hurricane Center Miami FL EP122024
800 PM PDT Thu Oct 24 2024

Kristy remains a very powerful hurricane. A ring of intense deep
convection is relatively symmetric around the eye. However, the eye
itself has lost some definition during the past few hours. The
latest satellite intensity estimates range from about 130 kt to 140
kt, and based on that data, and the slightly degraded satellite
appearance, the initial intensity is nudged downward to 135 kt. An
ASCAT-C pass from several hours ago indicated that Kristy was a
little larger than previously estimated, but still smaller than
average.

The major hurricane continues to move westward at about 12 kt to
the south of a ridge near Baja California. A gradual turn to the
northwest and then the north-northwest is forecast on Friday and
over the weekend as Kristy moves around the ridge. The system is
also expected to slow down as a trough approaches from the west,
causing the steering currents to weaken. The models have trended a
little to the north this cycle, and the NHC track forecast has been
adjusted in that direction.

Kristy will likely maintain its strength overnight as it remains in
an environment of low wind shear, relatively high moisture, and
over warm 28 degree C waters. However, a combination of much
stronger southeasterly wind shear and progressively cooler waters
should promote rapid weakening beginning Friday night. The NHC
intensity forecast is near the high end of the model guidance, but
in fair agreement with the HCCA and IVCN consensus models. Kristy
is expected to become a remnant low by day 3 and dissipate by day 4.

FORECAST POSITIONS AND MAX WINDS

INIT 25/0300Z 14.7N 122.7W 135 KT 155 MPH
12H 25/1200Z 15.4N 124.4W 135 KT 155 MPH
24H 26/0000Z 17.0N 126.5W 120 KT 140 MPH
36H 26/1200Z 18.9N 128.2W 100 KT 115 MPH
48H 27/0000Z 20.9N 129.4W 75 KT 85 MPH
60H 27/1200Z 22.2N 130.3W 50 KT 60 MPH
72H 28/0000Z 22.5N 131.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 29/0000Z...DISSIPATED

$$
Forecaster Cangialosi/Moore

[Cyclenall]

Strange how the NHC discussion doesn't mention the ERC:

Kristy will likely maintain its strength overnight as it remains in
an environment of low wind shear,

Huh?

However, the eye
itself has lost some definition during the past few hours.

Looks like it collapsed and fast.

[cycloneye]

Hurricane Kristy Discussion Number 15
NWS National Hurricane Center Miami FL EP122024
200 AM PDT Fri Oct 25 2024

Kristy is starting to lose organization due to increasing shear,
with the eye becoming ragged and cloud-filled and the surrounding
convection becoming less symmetric. Satellite intensity estimates
have been decreasing and now generally range from 115-140 kt.
Based on the the decreasing trend, the initial intensity is reduced
to a possibly generous 130 kt.

Kristy is now moving west-northwestward with the initial motion is
295/12 kt. During the next 2-3 days, the cyclone should move
northwestward to north-northwestward as it goes around the
southwest side of a mid- to upper-level ridge centered near Baja
California. Some decrease in the forward speed is expected by the
end of the forecast period as the cyclone shears apart, with the
low-level center moving slowly westward between 60-72 h. The
models have again trended a little to the north, especially from
24-48 h. Thus, this part of the forecast track has also been
nudged northward. The remnants of Kristy should move southwestward
in the low-level wind flow.

Vertical shear over the hurricane is going to increase from
light-to-moderate this morning to strong by 24 h. In addition, the
forecast track takes the system over steadily decreasing sea
surface temperatures. Based on this, gradual weakening is expected
for the next 12 h or so, followed by rapid weakening for the
remainder of the cyclone's life. Kristy is expected to drop below
hurricane strength by 48 h, and it is expected to degenerate to a
remnant low pressure area by 72 h. The global models forecast the
low to weaken to a trough by 96 h, and the intensity forecast
follows that in showing dissipation by that time.


FORECAST POSITIONS AND MAX WINDS

INIT 25/0900Z 15.2N 123.9W 130 KT 150 MPH
12H 25/1800Z 16.2N 125.4W 125 KT 145 MPH
24H 26/0600Z 17.9N 127.2W 110 KT 125 MPH
36H 26/1800Z 19.9N 128.7W 85 KT 100 MPH
48H 27/0600Z 21.7N 129.6W 60 KT 70 MPH
60H 27/1800Z 22.8N 130.3W 40 KT 45 MPH
72H 28/0600Z 23.0N 131.1W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 29/0600Z...DISSIPATED

$$
Forecaster Beven

[Pasmorade]

Hurricane Kristy Discussion Number 16
NWS National Hurricane Center Miami FL EP122024
800 AM PDT Fri Oct 25 2024

Southerly to southwesterly wind shear is starting to take its toll
on Kristy as the system is losing organization. The eye has become
cloud filled during the last several hours, with the convective
pattern becoming more asymmetric. Deep convection continues to wrap
within the eyewall, although a recent AMSR2 microwave pass
depicts the inner core is starting to erode. Objective and
subjective intensity estimates have been decreasing steadily this
morning and range from 105-115 kt. Using a blend of these
estimates, the initial intensity for this advisory is set to 110 kt.

Kristy is moving toward the west-northwest with an estimated motion
of 300/12 kt. The system will move more northwestward to
north-northwestward for the next few days, steered along the
southwestern periphery of a ridge located over the eastern Pacific.
Towards the end of the period, as the system weakens and becomes a
remnant low, Kristy's forward speed will also decrease with a turn
toward the west-southwest within the low-level flow. The NHC
forecast is very near the previous one with a slight nudge
northward, towards the corrected and simple consensus track aids.

The environment along the forecast path of Kristy is only becoming
increasingly hostile. Vertical wind shear is forecast to continue to
rise, with cooling sea-surface temperatures and drier mid-levels of
the atmosphere. Thus, steady to rapid weakening is anticipated
through the forecast period. Model simulated satellite data depicts
that Kristy will struggle to produce convection late this
weekend, becoming a post-tropical cyclone in 60 h, and dissipating
into a trough by 96 h. The latest NHC intensity forecast follows
these model trends.


FORECAST POSITIONS AND MAX WINDS

INIT 25/1500Z 15.8N 124.8W 110 KT 125 MPH
12H 26/0000Z 17.0N 126.2W 100 KT 115 MPH
24H 26/1200Z 18.8N 127.8W 85 KT 100 MPH
36H 27/0000Z 20.8N 128.9W 65 KT 75 MPH
48H 27/1200Z 22.4N 129.7W 45 KT 50 MPH
60H 28/0000Z 23.0N 130.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 28/1200Z 22.4N 131.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 29/1200Z...DISSIPATED

$$
Forecaster Kelly

[aspen]

EWRC is well underway:

https://i.postimg.cc/PJYW8Wf2/goes18-ir-12-E-202410241925.gif

Looked like it was briefly making a run for T7.5 before the EWRC kicked in. Now it’s collapsing fast.

[Hurricane2022]

2024 hasn't produced any cool and fun donut to track so far. I hope Kristy becomes one before the NHEM hurricane season ends.

[Hurricane2022]

 https://x.com/zeb199818/status/1849209943708336162


 https://x.com/zeb199818/status/1849251485332459922


 https://x.com/zeb199818/status/1849570988364792311


 https://x.com/zeb199818/status/1849574052756848804

[WaveBreaking]

Kristy staring back at the GOES satellite

[Sciencerocks]

[Travorum]

The evolution of Kristy's ERC from 04z to 17z. You can see the full lifecycle; The first pass shows the outer band beginning to wrap all the way around, the second pass shows that spiral band transition to a distinct but not yet dominant outer eyewall, and the third pass shows the outer eyewall dominant and choking off the inner eyewall:

---

Bonus, 14z SAR pass shows the dual wind maxima and the inner eyewall eroding:

[cycloneye]

Hurricane Kristy Discussion Number 17
NWS National Hurricane Center Miami FL EP122024
200 PM PDT Fri Oct 25 2024

Latest satellite images continue to depict that Kristy is
struggling within an increasingly hostile environment. The
convective pattern has continued to become more asymmetric, as
southerly vertical wind shear continues to increase, displacing most
of the convection over the northern semicircle. The eyewall has
weakened as well, with convective cloud tops warming. The inner core
degradation was further confirmed by a recent GMI microwave pass.
Subjective and objective intensity estimates continue to plummet
this afternoon and range between 90-105 kt. Given the satellite
presentation, inner structure degradation, and these estimates, the
initial intensity is lowered to 100 kt for this advisory.

Kristy is moving toward the northwest with an estimated motion of
305/12 kt. The system will move northwestward to north-northwestward
for the next couple of days, steered along the southwestern
periphery of a ridge located over the eastern Pacific. Towards the
end of the period, as the system weakens and becomes a remnant low,
the system's forward speed will also decrease with a turn toward the
west-southwest within the low-level flow. The NHC track forecast is
very near the previous one.

The environment surrounding Kristy continues to become more and more
unfavorable. Vertical wind shear is forecast to continue to
increase, with cooling sea-surface temperatures and drier mid-levels
of the atmosphere. Therefore, steady to rapid weakening is
anticipated through the forecast period. Model simulated satellite
data depict that Kristy will struggle to produce convection late
this weekend, becoming a post-tropical cyclone in 48 h, and
dissipating into a trough by 72 h. The latest NHC intensity forecast
follows these model trends.


FORECAST POSITIONS AND MAX WINDS

INIT 25/2100Z 16.8N 125.8W 100 KT 115 MPH
12H 26/0600Z 18.0N 127.1W 90 KT 105 MPH
24H 26/1800Z 20.0N 128.6W 70 KT 80 MPH
36H 27/0600Z 22.0N 129.6W 50 KT 60 MPH
48H 27/1800Z 22.8N 130.5W 35 KT 40 MPH...POST-TROPICAL
60H 28/0600Z 22.7N 131.4W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 28/1800Z...DISSIPATED

$$
Forecaster Kelly

[cycloneye]

Hurricane Kristy Discussion Number 18
NWS National Hurricane Center Miami FL EP122024
800 PM PDT Fri Oct 25 2024

Kristy's deepest convection is being displaced to the north of the
center due to strong southerly shear, diagnosed at 30 kt by
UW-CIMSS, although some convective elements are still trying to
form within the southern eyewall. Subjective Dvorak CI numbers and
objective satellite estimates now range between 80-100 kt, and
Kristy's intensity is therefore set at a blend of 90 kt. Rapid
weakening is forecast to continue as the hurricane encounters even
stronger shear--and cooler sea surface temperatures--over the next
couple of days. The NHC intensity forecast closely follows previous
official forecast trends and the latest consensus aids.
Model-simulated satellite data indicate that Kristy should lose its
deep convection by Sunday, and the cyclone is therefore expected to
degenerate into a remnant low by 48 hours. The low is forecast to
open up into a trough on Monday.

Kristy is moving northwestward (310/13 kt), steered by a strong
mid-level ridge centered over the Baja California peninsula. The
ridge should keep Kristy on a northwestward or north-northwestward
trajectory for the next 36 hours, but once the cyclone weakens to a
remnant low, it is expected to turn westward and slow down
considerably when it runs into a low-level ridge to the north.
The track models are in good agreement on this scenario, and no
significant track changes were made from the previous forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 26/0300Z 17.6N 126.9W 90 KT 105 MPH
12H 26/1200Z 18.9N 128.0W 75 KT 85 MPH
24H 27/0000Z 20.9N 129.2W 55 KT 65 MPH
36H 27/1200Z 22.4N 130.1W 40 KT 45 MPH
48H 28/0000Z 22.7N 130.8W 30 KT 35 MPH...POST-TROP/REMNT LOW
60H 28/1200Z 22.4N 131.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 29/0000Z...DISSIPATED

$$
Forecaster Berg