EPAC: CARLOTTA - Post-Tropical - Discussion

[cycloneye]

Hello Carlotta. Wont change the title until is oficial.

EP, 03, 2024073118, , BEST, 0, 159N, 1077W, 40, 1003, TS, CARLOTTA

[Yellow Evan]

EP, 03, 202407311800, 10, DVTS, CI, , 1570N, 10800W, , 2, 45, 2, 1000, 2, DVRK, , , , , , , , , , , , , , E, TAFB, ERA, VI, 3, 3030 /////, , , GOES18, CSC, T,

[Yellow Evan]

31/1800 UTC 15.9N 107.6W T2.5/2.5 03E -- East Pacific

[Sciencerocks]

 https://x.com/wutxori/status/1818723033613582748

[Sciencerocks]

[cycloneye]

New peak intensity up to 85kt.

BULLETIN
Tropical Storm Carlotta Advisory Number 2
NWS National Hurricane Center Miami FL EP032024
200 PM MST Wed Jul 31 2024

...DEPRESSION INTENSIFIES INTO TROPICAL STORM CARLOTTA...
...FORECAST TO BECOME A HURRICANE AT THE END OF THIS WEEK
AS IT MOVES AWAY FROM MEXICO...


SUMMARY OF 200 PM MST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...16.2N 108.0W
ABOUT 310 MI...500 KM SW OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES




Tropical Storm Carlotta Discussion Number 2
NWS National Hurricane Center Miami FL EP032024
200 PM MST Wed Jul 31 2024

The convective structure of the depression has continued to improve
this afternoon, with plenty of curved bands on satellite imagery
wrapping cyclonically around a well-defined center. After the prior
advisory, a late arriving SSMIS pass also showed these cyclonic
bands well on the 37-GHz channel. Subjective Dvorak intensity
estimates were T3.0/45-kt from TAFB and T2.5/35-kt from SAB. Given
the improvement in structure, the initial intensity is set at 40 kt
this advisory, upgrading Tropical Depression Three-E to Tropical
Storm Carlotta, the third named storm of the slow-starting 2024 East
Pacific Hurricane Season.

Carlotta has been moving a bit more poleward that previously
expected, with the most recent 12-h motion averaging around
305/12-kt. This northwestward motion is soon expected to turn back
more westward as it comes under the influence of a large deep-layer
ridge centered over the southwestern United States. The global model
guidance continues to advertise a broad weakness in this ridging
forming on its western side by days 4-5, and a slowdown with some
poleward turn is possible in Carlotta's track by the end of the
forecast period. Overall, the guidance this cycle has shifted more
northward than before, partially due to the initial position, but
the NHC track forecast remains in good agreement with the consensus
aids, in between the GFS and ECMWF solutions.

The improvement in Carlotta's structure also could mean it is more
poised to intensify faster than previously expected in the
short-term. This possibility is reflected by the latest intensity
guidance which is notably higher than before, showing Carlotta
taking advantage of the favorable low vertical wind shear and warm
sea-surface temperatures. In fact, the latest SHIPS rapid
intensification (RI) index now indicates a 30-40 percent chance of
RI over the next 24 hours. While the NHC intensity forecast will not
quite show this rate of intensification yet, it is higher than
before, and now peaks Carlotta as a 85-kt Category 2 hurricane in
60-72 hours. This intensity forecast is is pretty good agreement
with the latest HFIP Corrected Consensus Approach (HCCA) forecast,
but is now a shade under the latest HAFS-A/B forecast. Carlotta is
still expect to begin moving over cooler waters by days 4-5 which
should begin to induce a gradual weakening by the end of the
forecast period.


FORECAST POSITIONS AND MAX WINDS

INIT 31/2100Z 16.2N 108.0W 40 KT 45 MPH
12H 01/0600Z 16.8N 109.8W 50 KT 60 MPH
24H 01/1800Z 17.3N 111.8W 60 KT 70 MPH
36H 02/0600Z 17.7N 113.9W 70 KT 80 MPH
48H 02/1800Z 17.8N 116.0W 80 KT 90 MPH
60H 03/0600Z 17.8N 118.2W 85 KT 100 MPH
72H 03/1800Z 17.8N 120.2W 85 KT 100 MPH
96H 04/1800Z 18.3N 122.2W 75 KT 85 MPH
120H 05/1800Z 19.3N 124.0W 65 KT 75 MPH

$$
Forecaster Papin

[cycloneye]

Eye forming?

[cycloneye]

 https://x.com/philklotzbach/status/1818759574209675356

[Sciencerocks]

Eye forming?

https://i.imgur.com/nq1B8Gg.gif

Looks like a banding eye...This is kind of shown on microwave too. Probably 55 knots and could become a can within the next 24 hours.

[Kingarabian]

Eye forming?

https://i.imgur.com/nq1B8Gg.gif

Sort of. Looks more like a dry slot but clearly an eyewall forming.

[cycloneye]

Tropical Storm Carlotta Discussion Number 3
NWS National Hurricane Center Miami FL EP032024
800 PM MST Wed Jul 31 2024

Carlotta continues to show signs of organization this evening.
Geostationary satellite imagery has shown regular bursts of deep
convection with cloud top temperatures below -80 degrees C near the
center of the storm. Microwave satellite imagery from AMSR2 also
revealed decent structure of the low-level center. Dvorak satellite
estimates from TAFB and SAB agree Carlotta's intensity is 45 kt,
and the initial intensity has been increased to match these
estimates.

The storm is moving west-northwestward at about 10 kt. Carlotta is
expected to gradually turn more westward in about a day or so as a
ridge builds over the southwestern United States. By Sunday, the
storm is expected to turn back to the west-northwest and slow as it
reaches a weakness in the ridge. The latest official track forecast
has once again shifted slightly north from the previous forecast and
has a slightly quicker along-track speed.

Signs are pointing towards Carlotta rapidly intensifying over the
next day or so. The storm is moving over warm waters, and the
environmental shear is expected to remain weak. Statistical model
guidance indices show between a 30 to 40 percent chance of rapid
intensification (RI) in the next 24 h. This model guidance, paired
with the latest structural information provided by satellite
imagery, are the basis for now explicitly forecasting RI in the next
24 h. This period of RI could be interrupted in a day or so by an
increase in vertical wind shear, though the global models differ in
evolution of upper-level winds, making the intensity forecast
somewhat uncertain. The latest intensity forecast lies close to the
corrected consensus aid, HCCA, and the peak has been increased to 90
kt at 60 hours.

FORECAST POSITIONS AND MAX WINDS

INIT 01/0300Z 16.6N 108.9W 45 KT 50 MPH
12H 01/1200Z 17.2N 110.5W 60 KT 70 MPH
24H 02/0000Z 17.7N 112.5W 75 KT 85 MPH
36H 02/1200Z 18.0N 114.7W 80 KT 90 MPH
48H 03/0000Z 18.0N 116.9W 85 KT 100 MPH
60H 03/1200Z 18.0N 118.9W 90 KT 105 MPH
72H 04/0000Z 18.1N 120.8W 85 KT 100 MPH
96H 05/0000Z 18.7N 122.9W 75 KT 85 MPH
120H 06/0000Z 19.4N 124.8W 55 KT 65 MPH

$$
Forecaster Bucci

[Sciencerocks]

[Ubuntwo]

Low-level eye on microwave

[Kingarabian]

Low-level eye on microwave
https://i.imgur.com/1ChDp4z.png

Yeah 45kts was pretty conservative considering the eyewall was clearly 3/4th wrapped around on visible, 2 hours before the advisory. Currently, it's likely bordering on hurricane status.

[HurricaneRyan]

The EPAC producing a decent system at all this season is nice.

[cycloneye]

Tropical Storm Carlotta Discussion Number 4
NWS National Hurricane Center Miami FL EP032024
200 AM MST Thu Aug 01 2024

Carlotta has continued to strengthen tonight. A series of earlier
SSMIS and GMI passive microwave images show that the storm has
become better organized, with deep convection wrapping around the
center and a formative mid-level eye becoming apparent in the 89-GHz
channel. Unfortunately, no recent scatterometer data is available to
better assess the size or intensity of Carlotta. TAFB and SAB
provided T-3.0/45 kt subjective Dvorak estimates, while the UW-CIMSS
objective satellite intensity estimates range from 41-55 kt. The
initial intensity of the storm is raised to 50 kt based on a blend
of these estimates.

A ridge over the southwestern United States is steering Carlotta
west-northwestward at about 10 kt, and this general motion is
expected to continue today. As the ridge strengthens to the north of
the storm, Carlotta is forecast to turn westward on Friday and
continue on that heading through the weekend. The track models are
in good agreement through the first few days of the forecast period,
with increased spread noted thereafter in the deterministic models
and global ensembles. The updated NHC track forecast lies slightly
to the right of the previous track and is a bit faster in the longer
range, following the latest multi-model consensus aid trends.

Very warm SSTs and relatively low deep-layer shear appear favorable
for significant to possibly rapid intensification of Carlotta during
the next couple of days. Given that the microwave data suggest an
inner core could be solidifying, Carlotta seems likely to take
advantage of these favorable conditions and is expected to become a
hurricane later today. The NHC forecast is very similar to the
previous one, remaining on the high end of the intensity guidance
envelope early in the forecast period and showing continued
strengthening through early Saturday. The forecast track brings the
storm over gradually cooler waters from 72-120 h, which should
induce weakening by early next week.


FORECAST POSITIONS AND MAX WINDS

INIT 01/0900Z 17.0N 109.9W 50 KT 60 MPH
12H 01/1800Z 17.6N 111.5W 65 KT 75 MPH
24H 02/0600Z 17.9N 113.7W 75 KT 85 MPH
36H 02/1800Z 18.1N 115.8W 80 KT 90 MPH
48H 03/0600Z 18.2N 118.0W 85 KT 100 MPH
60H 03/1800Z 18.3N 120.0W 90 KT 105 MPH
72H 04/0600Z 18.5N 121.4W 85 KT 100 MPH
96H 05/0600Z 19.0N 124.0W 70 KT 80 MPH
120H 06/0600Z 19.5N 126.5W 55 KT 65 MPH

$$
Forecaster Reinhart

[Yellow Evan]

This is bombing out just based on IR loops, although it eventually needs more convection upshear. Dvorak only at 3.0 so lagging behind.

[cycloneye]

SUMMARY OF 800 AM MST...1500 UTC...INFORMATION
----------------------------------------------
LOCATION...17.2N 111.0W
ABOUT 455 MI...735 KM WSW OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 800 AM MST (1500 UTC), the center of Tropical Storm Carlotta was
located near latitude 17.2 North, longitude 111.0 West. Carlotta is
moving toward the west-northwest near 12 mph (19 km/h). This motion
is expected to continue today, followed by a turn toward the west on
Friday and a continued westward motion through the weekend.

Maximum sustained winds are near 60 mph (95 km/h) with higher gusts.
Strengthening is forecast during the next couple of days, and
Carlotta is expected to become a hurricane either tonight or
tomorrow.

Tropical-storm-force winds extend outward up to 60 miles (95 km)
from the center.

The estimated minimum central pressure is 997 mb (29.44 inches).





Tropical Storm Carlotta Discussion Number 5
NWS National Hurricane Center Miami FL EP032024
800 AM MST Thu Aug 01 2024

After intensifying over the past 12 to 18 hours, Carlotta is taking
a brief pause as the inner-core becomes better established, though
the system is still quite healthy looking on satellite imagery with
plenty of curved bands around a formative central dense overcast
(CDO). A blend of the latest subjective Dvorak intensity estimates
still support an intensity of 50-kt this advisory, which is also
roughly in the middle of objective intensity guidance.

Carlotta continues to move west-northwestward at 295/10-kt. This
motion is caused by a prominent deep-layer ridge located over the
southwestern United States, and Carlotta may turn more back westward
over the next few days as this ridge continues to strengthen.
However by day 3 and beyond, the tropical cyclone will begin to
feel a weakness to the north, which will likely result in a gradual
slowdown in its forward motion and another gentle shift more
poleward in the track. The latest track guidance is ever so slightly
further north and faster compared to the previous cycle. Thus, the
NHC track forecast has been shifted a bit in that direction,
roughly in between the prior track forecast, and the reliable
consensus aids TVCE and HCCA.

Environmental conditions still appear quite favorable for
intensification, with warm 28-29 C sea-surface temperatures (SSTs),
and low to moderate shear between 10-15 kt out of the northwest. The
rate of intensification may be determined more by how Carlotta's
inner-core evolves, and there have not been any recent microwave
images to diagnose the current structure. The SHIPS rapid
intensification index is a little lower than last night, though this
could also be in response to the temporary pause in the
intensification. However the last few GOES-18 images suggest the CDO
is becoming better established though an eye has yet to fully appear
on first-light visible imagery. Even though the intensity guidance
has shifted a little lower than last night, I have elected to keep
the same intensification rate in the NHC forecast from the last
cycle over the next 24 hours. This forecast is in better agreement
with the regional-hurricane models HAFS-A/B versus the lower
consensus aids that have been influenced by the lower SHIPS and LGEM
guidance. After 48-60 hours, SSTs begin to markedly decrease along
the forecast track, dropping under 26 C in 96 hours. Thus, the NHC
intensity forecast shows gradual weakening between days 3 to 5.


FORECAST POSITIONS AND MAX WINDS

INIT 01/1500Z 17.2N 111.0W 50 KT 60 MPH
12H 02/0000Z 17.9N 112.6W 65 KT 75 MPH
24H 02/1200Z 18.2N 114.8W 75 KT 85 MPH
36H 03/0000Z 18.3N 117.0W 85 KT 100 MPH
48H 03/1200Z 18.4N 119.2W 90 KT 105 MPH
60H 04/0000Z 18.6N 121.0W 85 KT 100 MPH
72H 04/1200Z 19.0N 122.7W 80 KT 90 MPH
96H 05/1200Z 19.5N 125.5W 65 KT 75 MPH
120H 06/1200Z 20.0N 128.0W 55 KT 65 MPH

$$
Forecaster Papin

[Sciencerocks]

[WaveBreaking]

Looks like Carlotta’s trying to form a pinhole eye