EPAC: CARLOTTA - Post-Tropical - Discussion

[cycloneye]

EP, 94, 2024072918, , BEST, 0, 117N, 979W, 25, 1009, LO

https://ftp.nhc.noaa.gov/atcf/btk/bep942024.dat

[ElectricStorm]

Both GFS and Euro make this a hurricane. Looks like we might finally have a chance to get a quality storm in the EPAC.

And the one behind it might have an even better chance

[cycloneye]

South of Southern Mexico (EP94):
An area of low pressure located a few hundred miles south of the
southern coast of Mexico continues to become better organized
based on satellite imagery. Environmental conditions appear
conducive for further development of this system, and a tropical
depression is likely to form within the next couple of days. The
system is forecast to move westward to west-northwestward at 10 to
15 mph during the next several days, remaining offshore of the
southern coast of Mexico.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 7 days...high...90 percent.

[Teban54]

Opening bids from 18z hurricane models:

• HWRF: 963.9 mb, 85.7 kt
• HMON: 989.9 mb, 50.3 kt (run ends while intensifying)
• HAFS-A: 974.6 mb, 66.6 kt (run ends while intensifying)
• HAFS-B: 977.7 mb, 61.5 kt (run ends while intensifying)

[Sciencerocks]

[Ubuntwo]

Structure looks to be ahead of model expectations to my eyes.

[Sciencerocks]

[Sciencerocks]

 https://x.com/VortixWx/status/1818262082573205964

[IcyTundra]

The GFS has really backed off on the intensity. It was suggesting that this could become a major hurricane for multiple days. Still going to be a hurricane most likely but no where close to what the GFS was showing for most of last week.

[cycloneye]

South of Southern Mexico (EP94):
Shower and thunderstorm activity is showing signs of organization
with an area of low pressure located a few hundred miles south of
the southern coast of Mexico. However, recently received satellite
wind data suggests the system does not yet possess a well-defined
center. Environmental conditions appear conducive for further
development of this system, and a tropical depression is expected to
form over the next day or two. The system is forecast to move
westward to west-northwestward at 10 to 15 mph during the next
several days, remaining offshore of the southern coast of Mexico.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 7 days...high...90 percent.

[Kingarabian]

Latest SSMIS passes only got half of the center but there are hints of a developing or developed LLC.

[Yellow Evan]

Latest ASCAT hints at a broad but closed low. Visible imagery shows a well defined MLC atop of the monsoon trough. There’s some northerly shear now but we have through at least Saturday before decreasing SSTs start to become an issue. Good chance this becomes a potent hurricane if we get genesis overnight.

[Sciencerocks]

[Kingarabian]

Clearly a TD has formed based on IR imagery.

[Yellow Evan]

ASCAT does not inspire confidence of a well-defined center.

[ElectricStorm]

0z Hurricane model runs:
HWRF 85kts/960mb
HMON fluctuates between Cat 1/2
HAFS-A 972mb but winds remain in the high TS range
HAFS-B 90kts/pressure fluctuates in the 960s

Solid support for a least a Cat 1 hurricane but not much support for a major this cycle

[cycloneye]

South of Southwestern Mexico (EP94):
Shower and thunderstorm activity is gradually becoming more
organized near an area of low pressure located a few hundred miles
south-southwest of Manzanillo, Mexico. If these current trends
continue, this system is expected to become a tropical depression as
soon as later this morning. The system is forecast to move westward
to west-northwestward at 10 to 15 mph during the next several days,
remaining offshore of the southern coast of Mexico.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 7 days...high...90 percent.

[Sciencerocks]

[Subtrop]

EP, 03, 2024073112, , BEST, 0, 149N, 1067W, 30, 1007, TD, 34, NEQ, 0, 0, 0, 0, 1010, 180, 40, 0, 0, E, 0, , 0, 0, THREE-E, S, 0, , 0, 0, 0, 0, genesis-num, 013, TRANSITIONED, epA42024 to ep032024,

https://www.ssd.noaa.gov/PS/TROP/DATA/A ... 032024.dat

[cycloneye]

Tropical Depression Three-E Discussion Number 1
NWS National Hurricane Center Miami FL EP032024
800 AM MST Wed Jul 31 2024

Over the last few hours, the convective organization has improved
with the area of low pressure we have been monitoring a few hundred
miles off the southwestern coast of Mexico. First-light visible
imagery from a GOES-West meso-sector over the storm show the
development of organized curve banding, with low-level cloud motions
also now suggesting the presence of closed cyclonic flow. This
improved convective structure was also seen in an earlier 1040 UTC
SSMIS microwave pass. In addition, the latest set of subjective
Dvorak intensity estimates were both at T2.5/35 kt from both SAB and
TAFB. All these data suggest that the system has become a tropical
cyclone, and advisories are being initiated at this time. The
initial intensity for this advisory is set at 30 kt, a little under
the Dvorak estimates given the lower objective estimates and
earlier scatterometer data.

The initial estimated motion is off to the west-northwest at
295/12-kt. This motion is expected to continue with a gentle
turn more westward over the next few days as the system becomes
primarily steered by a deep-layer ridge located over the
southwestern United States. Towards the end of the forecast period,
there could be a bit more of a weakness in this ridge on its
western extent, potentially allowing the system to turn more
poleward again. The initial track forecast in general sticks close
to the consensus aids TVCE and HCCA, which favor a track that is in
between the operational GFS and ECMWF tracks, but slightly in favor
of the latter.

Intensity-wise, TD3-E might be our first system in the East Pacific
to last longer than a couple of days, with most of the guidance
suggesting intensification into the weekend. SHIPS guidance from
both the GFS and ECMWF suggest the shear will remain low (less than
15 kt) while sea-surface temperatures underneath the cyclone remain
in the 29-30 C range over the next few days. Such a favorable
environment could favor significant intensification once an
inner-core becomes established. Interestingly, the
regional-hurricane model guidance, while showing intensification, do
not currently forecast rapid intensification. The first NHC
intensity forecast shows more gradual intensification for the next
day or so, followed by a somewhat faster rate, peaking the system as
a Category 1 hurricane in 72 h, on the high end of the intensity
guidance. Towards the end of the forecast, the tropical cyclone
should begin to move over cooler ocean waters, with gradual
weakening expected to begin around day 4 or 5.


FORECAST POSITIONS AND MAX WINDS

INIT 31/1500Z 15.1N 107.2W 30 KT 35 MPH
12H 01/0000Z 15.7N 108.9W 35 KT 40 MPH
24H 01/1200Z 16.3N 110.9W 40 KT 45 MPH
36H 02/0000Z 16.7N 112.9W 50 KT 60 MPH
48H 02/1200Z 17.0N 115.0W 60 KT 70 MPH
60H 03/0000Z 17.0N 117.1W 70 KT 80 MPH
72H 03/1200Z 17.1N 119.0W 75 KT 85 MPH
96H 04/1200Z 18.0N 121.5W 70 KT 80 MPH
120H 05/1200Z 18.5N 123.5W 60 KT 70 MPH

$$
Forecaster Papin