EPAC: KRISTY - Remnants - Discussion

[Hurricane2022]

[Travorum]

Hurricane Kristy Discussion Number 7
NWS National Hurricane Center Miami FL EP122024
200 AM MST Wed Oct 23 2024

Kristy is rapidly strengthening this morning, with the latest
satellite imagery showing an eye developing in the central dense
overcast and good cirrus outflow in the western semicircle.
Objective and subjective satellite intensity estimates are now in
the 75-95 kt range, and the initial intensity is increased to a
possibly conservative 85 kt.

Kristy is moving 265/17 kt on the south side of the subtropical
ridge, and this general motion should continue for the next 36 h or
so. From 36-72 h, Kristy should turn northwestward toward a break
in the ridge caused by a large mid- to upper-level trough to the
northeast of the Hawaiian Islands. After that, strong upper-level
winds should cause the cyclone to shear apart, with the low-level
circulation turning westward on the south side of a low-level
ridge. The new forecast track is generally similar to the old track,
but is has been nudged northward between 60-96 h in response to a
northward shift in the guidance.

The hurricane should remain in an environment of light shear over
warm sea surface temperatures for the next 36 h or so, and thus
continued steady to rapid strengthening is expected during that
time. The first 36-48 h of the intensity forecast is at or a
little above the upper edge of the intensity guidance and calls for
a peak intensity of 120 kt. However, given current trends, it would
not be a surprise if Kristy got stronger than this. Later in the
forecast period, the cyclone should encounter strong southwesterly
shear and move over decreasing sea surface temperatures, and this
combination should cause steady to rapid weakening. This part of
the new intensity forecast calls for the system to weaken to a
tropical storm by 96 h and then quickly decay to a remnant low
pressure area by 120 h.


FORECAST POSITIONS AND MAX WINDS

INIT 23/0900Z 14.5N 112.0W 85 KT 100 MPH
12H 23/1800Z 14.3N 114.7W 105 KT 120 MPH
24H 24/0600Z 14.2N 118.0W 115 KT 130 MPH
36H 24/1800Z 14.2N 121.1W 120 KT 140 MPH
48H 25/0600Z 14.7N 123.8W 115 KT 130 MPH
60H 25/1800Z 15.7N 126.2W 110 KT 125 MPH
72H 26/0600Z 17.2N 128.3W 100 KT 115 MPH
96H 27/0600Z 20.0N 131.9W 60 KT 70 MPH
120H 28/0600Z 21.1N 135.5W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven

Looking pretty good for a low-end Cat 2

[Hurricane2022]

Hurricane Kristy Discussion Number 7
NWS National Hurricane Center Miami FL EP122024
200 AM MST Wed Oct 23 2024

Kristy is rapidly strengthening this morning, with the latest
satellite imagery showing an eye developing in the central dense
overcast and good cirrus outflow in the western semicircle.
Objective and subjective satellite intensity estimates are now in
the 75-95 kt range, and the initial intensity is increased to a
possibly conservative 85 kt.

Kristy is moving 265/17 kt on the south side of the subtropical
ridge, and this general motion should continue for the next 36 h or
so. From 36-72 h, Kristy should turn northwestward toward a break
in the ridge caused by a large mid- to upper-level trough to the
northeast of the Hawaiian Islands. After that, strong upper-level
winds should cause the cyclone to shear apart, with the low-level
circulation turning westward on the south side of a low-level
ridge. The new forecast track is generally similar to the old track,
but is has been nudged northward between 60-96 h in response to a
northward shift in the guidance.

The hurricane should remain in an environment of light shear over
warm sea surface temperatures for the next 36 h or so, and thus
continued steady to rapid strengthening is expected during that
time. The first 36-48 h of the intensity forecast is at or a
little above the upper edge of the intensity guidance and calls for
a peak intensity of 120 kt. However, given current trends, it would
not be a surprise if Kristy got stronger than this. Later in the
forecast period, the cyclone should encounter strong southwesterly
shear and move over decreasing sea surface temperatures, and this
combination should cause steady to rapid weakening. This part of
the new intensity forecast calls for the system to weaken to a
tropical storm by 96 h and then quickly decay to a remnant low
pressure area by 120 h.


FORECAST POSITIONS AND MAX WINDS

INIT 23/0900Z 14.5N 112.0W 85 KT 100 MPH
12H 23/1800Z 14.3N 114.7W 105 KT 120 MPH
24H 24/0600Z 14.2N 118.0W 115 KT 130 MPH
36H 24/1800Z 14.2N 121.1W 120 KT 140 MPH
48H 25/0600Z 14.7N 123.8W 115 KT 130 MPH
60H 25/1800Z 15.7N 126.2W 110 KT 125 MPH
72H 26/0600Z 17.2N 128.3W 100 KT 115 MPH
96H 27/0600Z 20.0N 131.9W 60 KT 70 MPH
120H 28/0600Z 21.1N 135.5W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven

Looking pretty good for a low-end Cat 2

The convection has recently completely wrapped in the W Eyewall, and the overall structure reminds me of Beryl. I think that this 85 kt is reasonable, but Kristy is certainly intensifying faster than Beryl did. I hope the NHC issues a TCU between this and the next adv to better follow this (V)RI that is likely happening rn.

[aspen]

Looked away from this disturbance for a few days and now it’s an ERI borderline major.

I have a sinking feeling we’re in for yet another significantly under-estimated storm, however.

[cheezyWXguy]

Looked away from this disturbance for a few days and now it’s an ERI borderline major.

I have a sinking feeling we’re in for yet another significantly under-estimated storm, however.

Hopefully that’s not the case but it wouldn’t shock me. Current appearance makes me think it’s well into cat3 now, but it’s probably fair to assume the winds are still catching up.

[cycloneye]

Cat 3

EP, 12, 2024102312, , BEST, 0, 144N, 1130W, 105, 958, HU

[Yellow Evan]

TXPZ29 KNES 231228
TCSENP

A. 12E (KRISTY)
B. 23/1200Z
C. 14.3N
D. 113.0W
E. ONE/GOES-W
F. T5.5/5.5
G. IR/EIR/SWIR
H. REMARKS...AN OW EYE SURROUNDED BY W AND EMBEDDED WITHIN LG RESULTS
IN AN ENO OF 5.0 AND AN EADJ OF +0.5 GIVING A DT OF 5.5. THE MET IS 5.0
BASED ON A RAPIDLY DEVELOPING TREND IN APPARENT INTENSITY OVER THE PAST
24 HOURS. THE PT IS 5.5. THE FT IS BASED ON THE DT.
I. ADDL POSITIONS
NIL

...HOSLEY

[Travorum]

09z microwave:

[WaveBreaking]

According to RAMMB SLIDER, Kristy is currently slabbing Nevada and California
Kinda funny that the outlines bugged out like this

[WaveBreaking]

Airmass RGB + Vis Sandwich

[Travorum]

Folks, I give you ARCHER's best guess at where Kristy's center is in red (its currently winning versus RAMMB SLIDER which has Kristy making landfall in Yosemite):

[cycloneye]

Hurricane Kristy Discussion Number 8
NWS National Hurricane Center Miami FL EP122024
800 AM MST Wed Oct 23 2024

The impressive rapid intensification of Kristy has continued this
morning. The gradually warming eye of the hurricane is surrounded by
a ring of very deep convection, with infrared cloud tops as cold as
-75 to -80 deg C. GOES-West derived motion winds indicate good
upper-level outflow, particularly over the southern and western
portions of the circulation. Subjective Dvorak classifications were
a consensus T5.5/102-kt from TAFB and SAB at 12 UTC. Satellite
trends suggest Kristy has kept strengthening since that time, and
the initial intensity is set at 110 kt, following the rising
objective estimates from UW-CIMSS.

The hurricane is moving quickly westward (265/17 kt) while being
steered by a strong subtropical ridge to its north. This quick
westward motion should continue for the next 24-36 h. Then, an
upper-level trough between the Hawaiian Islands and the west coast
of the United States is forecast to erode the western extent of the
ridge. As a result, Kristy is expected to move toward the
west-northwest and northwest late this week and into the weekend. A
westward motion is shown by day 5, as it is anticipated that Kristy
will become highly sheared and decoupled, with the vertically
shallow vortex steered by the low-level ridge. No significant
changes were made to the latest NHC track forecast.

Kristy is a relatively small hurricane that remains susceptible to
rapid intensity fluctuations in a weak shear environment over warm
SSTs. The latest GFS and ECMWF SHIPS output shows a 50 to 60 percent
chance of a 20-kt increase during the next 12 h, and the satellite
trends suggest continued near-term strengthening is likely. The
updated NHC forecast reflects these signals and lies above the
intensity guidance in the near term, showing Kristy peaking as a
category 4 hurricane on Thursday. By Friday, the aforementioned
trough is expected to impart increased shear on the hurricane, which
should induce weakening through the rest of the 5-day forecast
period. With SHIPS-diagnosed shear values of 40-50 kt by the
weekend, Kristy is forecast to quickly weaken over the weekend and
degenerate to a post-tropical remnant low by 120 h.


FORECAST POSITIONS AND MAX WINDS

INIT 23/1500Z 14.3N 113.9W 110 KT 125 MPH
12H 24/0000Z 14.2N 116.4W 125 KT 145 MPH
24H 24/1200Z 14.1N 119.7W 130 KT 150 MPH
36H 25/0000Z 14.3N 122.5W 125 KT 145 MPH
48H 25/1200Z 15.1N 125.1W 115 KT 130 MPH
60H 26/0000Z 16.5N 127.3W 105 KT 120 MPH
72H 26/1200Z 18.0N 129.3W 90 KT 105 MPH
96H 27/1200Z 20.5N 132.5W 55 KT 65 MPH
120H 28/1200Z 21.0N 136.5W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Reinhart

[Hurricane2022]

ace ace ace ace ace

FORECAST POSITIONS AND MAX WINDS

INIT 23/1500Z 14.3N 113.9W 110 KT 125 MPH
12H 24/0000Z 14.2N 116.4W 125 KT 145 MPH
24H 24/1200Z 14.1N 119.7W 130 KT 150 MPH
36H 25/0000Z 14.3N 122.5W 125 KT 145 MPH
48H 25/1200Z 15.1N 125.1W 115 KT 130 MPH
60H 26/0000Z 16.5N 127.3W 105 KT 120 MPH
72H 26/1200Z 18.0N 129.3W 90 KT 105 MPH
96H 27/1200Z 20.5N 132.5W 55 KT 65 MPH
120H 28/1200Z 21.0N 136.5W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Reinhart

[Sciencerocks]

[Sciencerocks]

 https://x.com/MichaelIgbino10/status/1849115618701652032

[xtyphooncyclonex]

For the love of ACE... I need Kristy to stay south!

[cheezyWXguy]

Looks like a mid range 4 now, eye really clearing out

[Travorum]

ADT CI# is up to 6.0 now with a raw T# of 6.6, and eye temps are definitively positive (cyclonicwx has the eye temp at +13.5C). The eye is starting to get a really circular shape on IR as well.

----- Current Analysis -----
Date : 23 OCT 2024 Time : 161021 UTC
Lat : 14:13:12 N Lon : 114:09:00 W


CI# /Pressure/ Vmax
6.0 / 949.2mb/115.0kt


Final T# Adj T# Raw T#
6.0 6.5 6.6

Estimated radius of max. wind based on IR : 13 km

Center Temp : +1.6C Cloud Region Temp : -71.7C

[aspen]

ADT CI# is up to 6.0 now with a raw T# of 6.6, and eye temps are definitively positive (cyclonicwx has the eye temp at +13.5C). The eye is starting to get a really circular shape on IR as well.

----- Current Analysis -----
Date : 23 OCT 2024 Time : 161021 UTC
Lat : 14:13:12 N Lon : 114:09:00 W


CI# /Pressure/ Vmax
6.0 / 949.2mb/115.0kt


Final T# Adj T# Raw T#
6.0 6.5 6.6

Estimated radius of max. wind based on IR : 13 km

Center Temp : +1.6C Cloud Region Temp : -71.7C

Strange that ADT only has +1.6C. Bad positioning again?

[Kingarabian]

ADT CI# is up to 6.0 now with a raw T# of 6.6, and eye temps are definitively positive (cyclonicwx has the eye temp at +13.5C). The eye is starting to get a really circular shape on IR as well.

----- Current Analysis -----
Date : 23 OCT 2024 Time : 161021 UTC
Lat : 14:13:12 N Lon : 114:09:00 W


CI# /Pressure/ Vmax
6.0 / 949.2mb/115.0kt


Final T# Adj T# Raw T#
6.0 6.5 6.6

Estimated radius of max. wind based on IR : 13 km

Center Temp : +1.6C Cloud Region Temp : -71.7C

Strange that ADT only has +1.6C. Bad positioning again?

That frame yes. But it's at +11C now.