EPAC: ALETTA - Remnants

[DorkyMcDorkface]

[gib]

July 4 is not actually a slow start (historical average is 2 by now), just in comparison...

https://www.storm2k.org/phpbb2/viewtopi ... 1#p3071511

It's the latest start in ~60 years. That's a pretty slow start.

[cycloneye]

Tropical Storm Aletta Discussion Number 3
NWS National Hurricane Center Miami FL EP012024
800 PM MST Thu Jul 04 2024

After maintaining a relatively well-organized structure on satellite
imagery for most of the day Thursday, Aletta appears a bit less
impressive over the past few hours. The latest objective intensity
estimates from UW-CIMSS range from 30-36 kt, while the subjective
numbers from TAFB and SAB range from 30-35 kt. At this time, there
is no reason to change the initial intensity estimate of 35 kt,
especially given that we should receive some ASCAT data within the
next couple of hours.

Although Aletta is currently located within an environment of low
vertical wind shear, the cyclone is forecast to reach cooler waters
and move into a drier airmass over the next 12 h or so. While it is
possible that Aletta could maintain its intensity for another 6 to
12 h, weakening is expected to commence by Friday morning, if not
sooner. Simulated satellite imagery from the GFS and ECMWF models
show Aletta losing its convection by late Friday, and the new NHC
forecast calls for Aletta to become a remnant low in 24 h.

Aletta has been moving a bit more quickly to the northwest or 305
degrees at 12 kt. A turn to the west is expected tonight. As Aletta
loses its convection, it will be steered westward to
west-southwestward by the low-level flow before it dissipates on
Saturday. The new NHC track forecast has been adjusted a bit farther
north and faster to the west, based mainly on the faster motion
observed over the past 6 hours.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0300Z 18.5N 108.0W 35 KT 40 MPH
12H 05/1200Z 18.6N 109.1W 30 KT 35 MPH
24H 06/0000Z 18.4N 110.6W 30 KT 35 MPH...POST-TROP/REMNT LOW
36H 06/1200Z 18.0N 112.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 07/0000Z...DISSIPATED

$$
Forecaster Hagen/Cangialosi

[cycloneye]

Tropical Storm Aletta Discussion Number 3
NWS National Hurricane Center Miami FL EP012024
800 PM MST Thu Jul 04 2024

After maintaining a relatively well-organized structure on satellite
imagery for most of the day Thursday, Aletta appears a bit less
impressive over the past few hours. The latest objective intensity
estimates from UW-CIMSS range from 30-36 kt, while the subjective
numbers from TAFB and SAB range from 30-35 kt. At this time, there
is no reason to change the initial intensity estimate of 35 kt,
especially given that we should receive some ASCAT data within the
next couple of hours.

Although Aletta is currently located within an environment of low
vertical wind shear, the cyclone is forecast to reach cooler waters
and move into a drier airmass over the next 12 h or so. While it is
possible that Aletta could maintain its intensity for another 6 to
12 h, weakening is expected to commence by Friday morning, if not
sooner. Simulated satellite imagery from the GFS and ECMWF models
show Aletta losing its convection by late Friday, and the new NHC
forecast calls for Aletta to become a remnant low in 24 h.

Aletta has been moving a bit more quickly to the northwest or 305
degrees at 12 kt. A turn to the west is expected tonight. As Aletta
loses its convection, it will be steered westward to
west-southwestward by the low-level flow before it dissipates on
Saturday. The new NHC track forecast has been adjusted a bit farther
north and faster to the west, based mainly on the faster motion
observed over the past 6 hours.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0300Z 18.5N 108.0W 35 KT 40 MPH
12H 05/1200Z 18.6N 109.1W 30 KT 35 MPH
24H 06/0000Z 18.4N 110.6W 30 KT 35 MPH...POST-TROP/REMNT LOW
36H 06/1200Z 18.0N 112.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 07/0000Z...DISSIPATED

$$
Forecaster Hagen/Cangialosi

[cycloneye]

Tropical Depression Aletta Discussion Number 5
NWS National Hurricane Center Miami FL EP012024
800 AM MST Fri Jul 05 2024

Multiple microwave images between 08 and 12 UTC indicated that
Aletta still has a well-defined center, and it has continued to
produce a small area of deep convection near that center. Objective
and subjective intensity estimates range from around 25 to 35 kt, so
the estimated maximum winds are still 30 kt for this advisory.
Aletta is moving westward (270/10kt) and a west-southwestward turn
is expected later this morning.

The small depression is located in a marginal environment, and a
combination of decreasing SSTs below 26 deg C, drier surrounding
air, and increasing shear should cause Aletta to lose its deep
convection later today. In fact, all dynamical guidance suggests
that Aletta will become a remnant low within the next 6 to 18 h. The
NHC forecast conservatively maintains Aletta as a tropical cyclone
on the longer side of that range, but still shows gradual weakening
through the forecast period. After it becomes a remnant low, Aletta
is expected to turn back toward the west and dissipate within
another day or so.


FORECAST POSITIONS AND MAX WINDS

INIT 05/1500Z 18.8N 109.8W 30 KT 35 MPH
12H 06/0000Z 18.5N 111.1W 30 KT 35 MPH
24H 06/1200Z 18.2N 112.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 07/0000Z 18.2N 114.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 07/1200Z...DISSIPATED

$$
Forecaster D. Zelinsky

[cycloneye]

 https://x.com/KacperWx/status/1809214536060121506

[Sciencerocks]

[Sciencerocks]

[cycloneye]

Tropical Depression Aletta Discussion Number 6
NWS National Hurricane Center Miami FL EP012024
200 PM MST Fri Jul 05 2024

Aletta is no longer producing organized deep convection. If this
current convective trend continues, Aletta will become a remnant low
later this evening. ASCAT-B data at 1712 UTC showed Aletta still has
a well-defined center, but indicated its maximum winds have
decreased to 25 kt.

The depression's initial motion estimate is 260/10 kt. Aletta
should generally remain on this heading with a similar forward
speed for the next day or so until it dissipates. Environmental
conditions around Aletta do not appear to be conducive for the
redevelopment of organized deep convection and all models indicate
that the cyclone will continue to weaken from this point.


FORECAST POSITIONS AND MAX WINDS

INIT 05/2100Z 18.6N 110.8W 25 KT 30 MPH
12H 06/0600Z 18.3N 112.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 06/1800Z 18.3N 113.8W 20 KT 25 MPH...POST-TROP/REMNT LOW
36H 07/0600Z...DISSIPATED

$$
Forecaster D. Zelinsky

[Charleswachal]

Why in the world did they name this system????

[cycloneye]

Bye.

Post-Tropical Cyclone Aletta Discussion Number 7
NWS National Hurricane Center Miami FL EP012024
800 PM MST Fri Jul 05 2024

Convection has continued to diminish in association with Aletta.
Little or no organized deep convection has been seen since late
Thursday morning. Both the GFS and the ECMWF simulated satellite
imagery do not indicate any return of deep convection. Given the
marginal environment, the remnant low should continue to spin down.
Aletta is forecast to dissipate on Saturday.

Do to the very poor appearance on satellite imagery and the lack of
any pressure gradients in the area, the initial intensity has been
lowered to 20 kt. Socorro Island measured a maximum wind of 21 kt a
few hours ago as Aletta passed just south of the island. Earlier
ASCAT-B data from 1712 UTC only showed peak winds in the 20-25 kt
range at that time.

No significant change has been made to the NHC track forecast.
Aletta should continue to be steered by the low-level flow in a
direction just south of due west until it dissipates.


FORECAST POSITIONS AND MAX WINDS

INIT 06/0300Z 18.4N 111.6W 20 KT 25 MPH...POST-TROPICAL
12H 06/1200Z 18.3N 112.8W 20 KT 25 MPH...POST-TROP/REMNT LOW
24H 07/0000Z...DISSIPATED

$$
Forecaster Hagen/Cangialosi

[Teban54]

Why in the world did they name this system????

Because it meets the criteria for a name storm. Duration is irrelevant even if it's only a TS for a few hours.