EPAC: LIDIA - Remnants - Discussion

[cycloneye]

Tropical Storm Lidia Discussion Number 20
NWS National Hurricane Center Miami FL EP152023
900 PM MDT Sat Oct 07 2023

The satellite presentation of Lidia has improved since yesterday.
Recent AMSR2 and SSMIS passive microwave images show signs of a
mid-level eye feature in the 89 GHz channel. However, the vortex
still appears tilted, with the low-level 37 GHz center situated to
the northeast of the mid-level center. While the upper-level outflow
is still restricted on the eastern side of the storm, the center has
been located deeper underneath the cold convective canopy today. As
a result, the satellite intensity estimates have risen, but they
seem a little high based on the earlier ASCAT data. The initial
intensity is raised to 60 kt, which is in best agreement with recent
UW-CIMSS SATCON and D-PRINT estimates.

The moderate easterly shear over Lidia is forecast to persist for
another 12-24 h, then weaken into early next week. The weaker
shear should allow Lidia to become more vertically aligned and
strengthen within a diffluent upper-level environment while moving
over very warm waters. Most of the intensity guidance shows
strengthening after 24 h while Lidia moves toward the coast of
Mexico. The regional hurricane models (HAFS, HWRF, HMON) show some
potential for significant intensification, and overall it appears
more likely that Lidia reaches the coast at hurricane strength early
next week. As a result, the NHC intensity forecast has been raised
at 24-72 h, though it still lies below the IVCN and HCCA aids. Given
the large spread noted in the intensity guidance, future adjustments
are certainly possible.

Lidia has not moved much since the last advisory, and its estimated
initial motion is west-northwestward or 285/3 kt. The storm is
expected to slowly turn northward on Sunday while moving around the
western periphery of a mid-level ridge. Then, the southwesterly flow
ahead of an upper-level trough to the north will cause Lidia to
accelerate northeastward toward the west-central coast of Mexico.
The largest spread in the track models is related to the forward
speed of Lidia while it interacts with the trough. The GFS brings
Lidia inland over mainland Mexico about 24 h earlier than the rest
of the global models, and thus there is more uncertainty in the
longer-range track forecast. For now, the NHC track follows a
consensus approach and lies between the TVCE and HCCA aids, similar
to but slightly faster than the previous prediction.


Key Messages:

1. Lidia is forecast to strengthen to a hurricane while it moves
toward the west-central coast of Mexico early next week. There is an
increasing risk of strong winds and heavy rain for the Islas Marias
and portions of the west-central coast of Mexico. Interests in these
locations should closely monitor the latest forecast updates, as
watches could be required as early as Sunday.

2. Swells from Lidia will cause dangerous surf and rip current
conditions along the west coast of Mexico and the Baja California
peninsula during the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 08/0300Z 16.1N 112.6W 60 KT 70 MPH
12H 08/1200Z 16.8N 112.7W 60 KT 70 MPH
24H 09/0000Z 17.6N 112.6W 65 KT 75 MPH
36H 09/1200Z 18.3N 111.9W 65 KT 75 MPH
48H 10/0000Z 18.9N 110.5W 70 KT 80 MPH
60H 10/1200Z 19.8N 108.5W 75 KT 85 MPH
72H 11/0000Z 21.1N 105.9W 75 KT 85 MPH
96H 12/0000Z 24.0N 101.5W 30 KT 35 MPH...POST-TROP/INLAND
120H 13/0000Z...DISSIPATED

$$
Forecaster Reinhart

[Sciencerocks]

 https://twitter.com/VortixWx/status/1710856530898120965

[cycloneye]

Tropical Storm Lidia Discussion Number 21
NWS National Hurricane Center Miami FL EP152023
300 AM MDT Sun Oct 08 2023

Overnight GOES-18 Proxy-Vis satellite imagery and a recent SSMIS
microwave overpass indicate that Lidia's vertical structure remains
slightly tilted toward the north, with the center located near the
northern edge of the cloud mass. The initial intensity is held at 60
kt for this advisory and is based primarily on UW-CIMSS objective
intensity techniques of the Deep Multispectral and IR Intensity TC
estimators, which both yield an intensity estimate of 59 kt.

The statistical GFS/ECMWF SHIPS intensity guidance indicates
that the deep-layer shear impeding Lidia's intensification rate
during the past few days will decrease soon. This more conducive
upper wind pattern should cause the cyclone to become a more
vertically coherent system. Therefore, strengthening is expected
while Lidia traverses warm (29-30C) sea surface temperatures, and
Lidia is forecast to become a hurricane early Monday. The NHC
intensity is based on a blend of the IVCN consensus and the Decay
SHIPS and is just below the HFIP HCCA corrected consensus beyond
the 48-hour period, which indicates a peak of 85 kt.

Lidia is drifting generally north-northwestward or 335/2 kt,
and this slow generally northward motion is expected to continue
through today while the cyclone rounds the western periphery of a
subtropical ridge. On Monday, Lidia is forecast to turn toward the
north-northeast to northeast and accelerate toward the west-central
coast of Mexico in response to a major shortwave trough approaching
the system from the northeast. No significant changes were made to
the previous advisory and the new official track forecast lies
closely to the various multi-model consensus aids.



Key Messages:

1. Lidia is forecast to strengthen to a hurricane while it moves
toward the west-central coast of Mexico on Tuesday. There is an
increasing risk of strong winds and heavy rain for the Islas Marias
and portions of the west-central coast of Mexico. Interests in these
locations should closely monitor the latest forecast updates, as
watches could be required later today or tonight.

2. Swells from Lidia will cause dangerous surf and rip current
conditions along the west coast of Mexico and the Baja California
peninsula during the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 08/0900Z 16.4N 112.5W 60 KT 70 MPH
12H 08/1800Z 17.1N 112.6W 60 KT 70 MPH
24H 09/0600Z 17.9N 112.3W 65 KT 75 MPH
36H 09/1800Z 18.6N 111.3W 65 KT 75 MPH
48H 10/0600Z 19.3N 109.4W 75 KT 85 MPH
60H 10/1800Z 20.3N 106.9W 75 KT 85 MPH
72H 11/0600Z 21.9N 103.7W 35 KT 40 MPH...INLAND
96H 12/0600Z...DISSIPATED

$$
Forecaster Roberts

[Sciencerocks]

[Kingarabian]

Looked better yesterday. Also don't get how they went with a higher rate of intensification without a mid level eye and a severely tilted TC, and they now have this intensifying slower despite it developing a mid level eye and showing less tilt.

[Sciencerocks]

[cycloneye]

Tropical Storm Lidia Discussion Number 22
NWS National Hurricane Center Miami FL EP152023
900 AM MDT Sun Oct 08 2023

Lidia continues to be relatively steady state this morning.
Geostationary satellite images show little change in the convective
pattern, and recent microwave data indicate that the system remains
sheared with the low-level center located on the north side of the
thunderstorm activity. There is a large spread in the latest
satellite intensity estimates that currently range from 49-77 kt.
Given the structure of Lidia in microwave data, the initial
wind speed is held steady at 60 kt, closer to the lower end of the
intensity estimates.

The storm has been moving slowly north-northwestward at about 4 kt
over the past 12-18 hours. A turn to the north should occur later
today, followed by a considerably faster motion to the northeast or
east-northeast on Monday and Tuesday as a mid- to upper-level trough
approaches the cyclone. There is a fair amount of model spread on
how sharply Lidia turns to the right and how quickly it moves toward
the coast of Mexico. The NHC official track forecast has been
nudged to the left, or north, at 48 and 60 h toward the latest
consensus aids.

Given the current structure of Lidia and ongoing mid-level shear,
little change in strength seems likely during the next day or so.
However, the models show a more favorable upper-level pattern
developing over the system on Monday and Tuesday while it moves over
29-30 C SSTs. These conditions should allow Lidia to strengthen,
and it is expected to reach the coast of Mexico by late Tuesday as a
hurricane. Rapid weakening is expected after landfall. The NHC
intensity forecast lies near the middle of the guidance envelope and
is similar to the previous one.

Based on the latest forecast, Hurricane Watches will likely be
required for portions of west-central Mexico later today.


Key Messages:

1. Lidia is forecast to strengthen into a hurricane while it moves
toward the west-central coast of Mexico on Tuesday. There is an
increasing risk of strong winds and heavy rain for the Islas Marias
and portions of the west-central coast of Mexico. Interests in these
locations should closely monitor the latest forecast updates, as
watches will likely be required later today or tonight.

2. Swells from Lidia will cause dangerous surf and rip current
conditions along the west coast of Mexico and the Baja California
peninsula during the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT 08/1500Z 16.9N 112.8W 60 KT 70 MPH
12H 09/0000Z 17.6N 112.7W 60 KT 70 MPH
24H 09/1200Z 18.3N 112.2W 60 KT 70 MPH
36H 10/0000Z 19.0N 110.8W 65 KT 75 MPH
48H 10/1200Z 19.9N 108.5W 75 KT 85 MPH
60H 11/0000Z 21.3N 106.1W 70 KT 80 MPH
72H 11/1200Z 23.0N 103.2W 30 KT 35 MPH...INLAND
96H 12/1200Z...DISSIPATED

$$
Forecaster Cangialosi

[Sciencerocks]

[cycloneye]

Tropical Storm Lidia Discussion Number 23
NWS National Hurricane Center Miami FL EP152023
300 PM MDT Sun Oct 08 2023

Lidia has become a little better organized this afternoon.
Satellite images indicate that deep convection has been increasing
and gradually becoming more symmetric. However, microwave data
show that the low- and mid-level centers are still not well aligned,
and there is a notable southwest tilt with height. The initial
intensity is again held at 60 kt, near the low end of the satellite
estimates, but if the trends continue, Lidia could become a
hurricane tonight.

The storm has now turned northward at 6 kt. A faster motion to the
northeast and east-northeast is expected on Monday and Tuesday as a
mid- to upper-level trough approaches the system. There has not
been any significant change with the new models runs, with the GFS
remaining the fastest solution and the ECMWF the slowest. The NHC
track forecast has again been nudged northward this cycle toward
the latest consensus aids. Based on the latest guidance, Lidia will
likely make landfall in west-central Mexico late Tuesday.

Lidia could strengthen a little tonight or early Monday, but more
notable intensification seems likely late Monday and Tuesday in
part due to a favorable trough interaction while Lidia moves over
SSTs near 30 C. The models have trended higher this cycle and the
NHC intensity forecast has followed suit, and is in line with the
HCCA and IVCN models. Rapid weakening is expected after landfall
and Lidia will likely dissipate over central Mexico in a few days.

Based on the forecast and the track uncertainty, the government of
Mexico has issued Hurricane and Tropical Storm Watches for portions
of west-central Mexico.


Key Messages:

1. Lidia is expected to strengthen before it reaches west-central
Mexico, and hurricane and tropical storm conditions are possible in
the watch areas beginning Tuesday.

2. Heavy rains from Lidia will likely produce flash and urban
flooding, along with possible mudslides in areas of higher terrain
across the southern portions of the state of Sinaloa, western
portions of the state of Nayarit and coastal portions of Jalisco
in southwest Mexico.

3. Swells from Lidia will cause dangerous surf and rip current
conditions along the west coast of Mexico and the Baja California
peninsula during the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT 08/2100Z 17.6N 112.8W 60 KT 70 MPH
12H 09/0600Z 18.3N 112.4W 65 KT 75 MPH
24H 09/1800Z 18.9N 111.6W 65 KT 75 MPH
36H 10/0600Z 19.7N 109.8W 75 KT 85 MPH
48H 10/1800Z 20.9N 107.4W 80 KT 90 MPH
60H 11/0600Z 22.6N 104.7W 50 KT 60 MPH...INLAND
72H 11/1800Z 24.5N 102.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 12/1800Z...DISSIPATED

[NDG]

Lidia not looking too sexy this evening, huge outflow was seen racing away from it on its NE quadrant.

[Yellow Evan]

Serious dry air intrusion. Winds have likely dropped significantly.

[Sciencerocks]

[zzzh]

I don't think this is a strengthening 60kt TS.

[cycloneye]

Tropical Storm Lidia Discussion Number 24
NWS National Hurricane Center Miami FL EP152023
900 PM MDT Sun Oct 08 2023

Lidia's convective structure has become somewhat less organized
since this afternoon. The cloud tops have warmed and there has been
an overall decrease in the deep convection near the center. There
were some arc clouds noted in late evening visible satellite
images which suggests the system may have entrained some drier
mid-level air. Despite the recent loss of organization, the
initial intensity is held at 60 kt, which is a blend of the
various subjective and objective satellite estimates.

It is interesting to note that simulated satellite imagery from
the 18Z GFS and regional hurricane models showed a decrease in
convection this evening, but they also indicated a return of the
convection overnight, which is expected to lead to strengthening on
Monday. The upper-level winds over the system are forecast to
become more conducive for strengthening while Lidia moves over
slightly warmer SSTs on its approach to west-central Mexico. Much
of the dynamical model guidance calls for steady strengthening
beginning tomorrow, and the latest NHC forecast shows a slightly
higher peak intensity before landfall. This is in good agreement
within the latest HFIP corrected consensus model. It should be
mentioned that if Lidia is able to finally able to establish an
inner core within the next 12-24 hours, this intensity forecast
could be on the conservative side. Rapid weakening is expected
after Lidia moves inland over west-central Mexico. A 72-hour point
is provided for continuity but it is very likely that the cyclone
will have dissipated by that time.

Lidia is moving northward or 010 degrees at 6 kt. A faster motion
to the northeast and east-northeast is expected on Monday and
Tuesday as a mid- to upper-level trough approaches the storm from
the northwest. The track guidance has not changed much this cycle,
with the GFS still quite a bit faster than the remainder of the
dynamical aids. The NHC track forecast remains near the latest
consensus models, and is very similar to the previous official
forecast.


Key Messages:

1. Lidia is expected to strengthen before it reaches west-central
Mexico, and hurricane and tropical storm conditions are possible in
the watch areas beginning Tuesday.

2. Heavy rains from Lidia will likely produce flash and urban
flooding, along with possible mudslides in areas of higher terrain
across the the state of Nayarit, southern portions of the state of
Sinaloa, and coastal portions of the state of Jalisco in western
Mexico.

3. A dangerous storm surge is expected near and to the south where
the center of Lidia moves over the Islas Marias and the coast of
west-central Mexico.

4. Swells from Lidia will cause dangerous surf and rip current
conditions along the west coast of Mexico and the Baja California
peninsula during the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT 09/0300Z 18.2N 112.6W 60 KT 70 MPH
12H 09/1200Z 18.8N 112.1W 60 KT 70 MPH
24H 10/0000Z 19.4N 110.8W 70 KT 80 MPH
36H 10/1200Z 20.3N 108.7W 80 KT 90 MPH
48H 11/0000Z 21.8N 106.1W 85 KT 100 MPH
60H 11/1200Z 23.7N 103.4W 35 KT 40 MPH...INLAND
72H 12/0000Z 25.6N 100.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 13/0000Z...DISSIPATED

[DioBrando]

Any chance this collapses before landfall?

[cycloneye]

Tropical Storm Lidia Discussion Number 25
NWS National Hurricane Center Miami FL EP152023
300 AM MDT Mon Oct 09 2023

Lidia's convective structure has improved during the last several
hours with deep bursts of convection, and cold cloud tops near -90
degrees Celsius at times. The low-level center has become embedded
beneath this recent burst as well. There is a fairly large range of
intensity estimates this advisory cycle, however. Subjective Dvorak
satellite final-T intensity estimates are a T4.0/ 65 kts, from both
TAFB and SAB. Objective satellite estimates from UW-CIMSS ADT and
AiDT are 51 kt and 61 kt, respectively. An ASCAT-B pass from a few
hours ago depicted a much weaker wind field around 35 kt, although
the convective pattern has markedly improved since that time. Using
a blend of these data, the initial intensity is set to an uncertain
55 kt for this advisory. The Air Force Hurricane Hunters are
scheduled to investigate the system later this afternoon, which will
provide valuable in-situ data to bring clarity to Lidia's intensity.

Vertical wind shear over the system is forecast to relax over the
next 24-36 hr while Lidia moves over warm sea surface temperatures
on its approach to west-central Mexico. Models are in fairly good
agreement with this strengthening scenario, and Lidia is forecast
to become a hurricane late today, with the peak intensity unchanged
from the previous advisory of 85 kt when the system is near the
coast of Mexico. The NHC intensity forecast lies near the HFIP
corrected consensus model, on the higher side of the guidance.
After Lidia makes landfall, rapid weakening is expected given the
high terrain, and the system is now forecast to dissipate by 60 h.

Lidia is moving north-northeastward or 020 degrees at 4 kt. A
faster motion to the northeast and east-northeast is expected later
today and Tuesday as a mid- to upper-level trough approaches the
system. The track guidance has shifted slightly south this
cycle, with still some along-track timing differences with the GFS
being the fastest. The NHC track forecast has been nudged
southward and lies near the various consensus aids.


Key Messages:

1. Lidia is expected to strengthen before it reaches west-central
Mexico, and hurricane conditions are expected within the Hurricane
Warning area on Tuesday, and hurricane and tropical storm
conditions are possible in the watch areas beginning Tuesday.

2. Heavy rains from Lidia will likely produce flash and urban
flooding, along with possible mudslides in areas of higher terrain
across the the state of Nayarit, southern portions of the state of
Sinaloa, and coastal portions of the state of Jalisco in western
Mexico.

3. A dangerous storm surge is expected near and to the south where
the center of Lidia moves over the Islas Marias and the coast of
west-central Mexico.

4. Swells from Lidia will cause dangerous surf and rip current
conditions along the west coast of Mexico and the Baja California
peninsula during the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT 09/0900Z 18.2N 112.4W 55 KT 65 MPH
12H 09/1800Z 18.7N 111.6W 60 KT 70 MPH
24H 10/0600Z 19.4N 109.7W 70 KT 80 MPH
36H 10/1800Z 20.7N 107.2W 85 KT 100 MPH
48H 11/0600Z 22.6N 104.4W 40 KT 45 MPH...INLAND
60H 11/1800Z...DISSIPATED

[Sciencerocks]

[Yellow Evan]

Looks much better today but not convinced the winds are as strong as the NHC indicates still.

[cycloneye]

Tropical Storm Lidia Discussion Number 26
NWS National Hurricane Center Miami FL EP152023
900 AM MDT Mon Oct 09 2023

Deep convection has been on the increase during the past several
hours, but it is unclear if it has resulted in Lidia strengthening
yet. Throughout Lidia's lifespan, there has been notable
uncertainty in the initial intensity, and it is no different at the
current time. The latest satellite intensity estimates span from
47 to 65 kt, and based on that data, the initial intensity is held
at 55 kt. However, the ASCAT data mentioned in the previous
discussion supported a lower wind speed estimate. The Air Force
Hurricane Hunters are currently en route to investigate Lidia, and
the data they collect should provide very valuable information in
estimating Lidia's intensity and structure.

Lidia has made the expected turn to the northeast, and the initial
motion is now estimated to be 045/5 kt. A mid- to upper-level
trough that is approaching Lidia should cause the storm to
accelerate to the northeast or east-northeast later today through
Tuesday. The models are in fair agreement on the overall path of
Lidia, but there is still a significant spread in the timing of
landfall with the GFS showing Lidia reaching the coast about 12
hours before the ECMWF shows landfall. The NHC track forecast
continues to lie between those solutions and remains close to the
various consensus models. Based on the forecast approach, Lidia
will likely reach the coast by late Tuesday.

The environmental conditions are becoming increasingly conducive for
strengthening. The storm is expected to move over SSTs near 30 C
and into a conducive upper-level wind pattern related to a favorable
trough interaction for the system. The models show significant or
rapid strengthening before Lidia reaches the coast, and the forecast
continues to follow suit and lies near the middle of the guidance
envelope. Rapid weakening is forecast once Lidia moves inland due
to the rugged terrain in west-central Mexico.

Key Messages:

1. Lidia is expected to strengthen before it reaches west-central
Mexico, and hurricane conditions are expected within the Hurricane
Warning area beginning Tuesday.

2. Heavy rains from Lidia will likely produce flash and urban
flooding, along with possible mudslides in areas of higher terrain
across the the state of Nayarit, southern portions of the state of
Sinaloa, and coastal portions of the state of Jalisco in western
Mexico.

3. A dangerous storm surge is expected near and to the south of
where the center of Lidia moves over the Islas Marias and the coast
of west-central Mexico.

4. Swells from Lidia will cause dangerous surf and rip current
conditions along the west coast of Mexico and the Baja California
peninsula during the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT 09/1500Z 18.5N 111.8W 55 KT 65 MPH
12H 10/0000Z 19.0N 110.6W 65 KT 75 MPH
24H 10/1200Z 20.0N 108.4W 80 KT 90 MPH
36H 11/0000Z 21.4N 105.9W 85 KT 100 MPH
48H 11/1200Z 23.1N 103.0W 30 KT 35 MPH...INLAND
60H 12/0000Z...DISSIPATED

$$
Forecaster Cangialosi

[Sciencerocks]