EPAC: 11-E - Remnants - Discussion

[Subtrop]

EP, 96, 2024093018, , BEST, 0, 136N, 956W, 25, 1007, DB, 34, NEQ, 0, 0, 0, 0, 1010, 100, 30, 0, 0, E, 0, , 0, 0, INVEST, S, 0, , 0, 0, 0, 0, genesis-num, 028, SPAWNINVEST, ep712024 to ep962024,

https://ftp.nhc.noaa.gov/atcf/btk/bep962024.dat

[Subtrop]

Special Outlook issued to increase the probability of tropical
cyclone formation for the disturbance near the Gulf of Tehuantepec.

South of the Gulf of Tehuantepec (96E):
Showers and thunderstorms associated with an area of low pressure
near the Gulf of Tehuantepec have quickly become better organized
during the past several hours. Environmental conditions are expected
to be conducive for additional development, and a tropical
depression could form as soon as tonight or tomorrow. This system is
forecast to meander for the next couple of days before drifting
northward towards the southern coast of Mexico, and interests there
should monitor the progress of this system. Regardless of
development, heavy rain is possible along most of the coast of
southern Mexico and northern Central America throughout this week.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 7 days...medium...50 percent.

[zhukm29]

2. South of the Gulf of Tehuantepec (96E):
Showers and thunderstorms associated with an area of low pressure
near the Gulf of Tehuantepec have continued to become better
organized this afternoon. Although the system does not yet appear to
have a well-defined surface circulation, environmental conditions
are expected to be conducive for additional development, and a
tropical depression is likely to form as soon as tonight or
tomorrow. This system is forecast to meander for the next couple of
days before drifting northward towards the southern coast of Mexico,
and interests there should monitor the progress of this system.
Regardless of development, heavy rain is possible along most of the
coast of southern Mexico and northern Central America throughout
this week.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 7 days...high...70 percent.

Jumped from lemon to cherry in 6 hours - looks like the NHC is taking this seriously after Otis and John, especially with the lack of good observations in this area.

[Kingarabian]

2. South of the Gulf of Tehuantepec (96E):
Showers and thunderstorms associated with an area of low pressure
near the Gulf of Tehuantepec have continued to become better
organized this afternoon. Although the system does not yet appear to
have a well-defined surface circulation, environmental conditions
are expected to be conducive for additional development, and a
tropical depression is likely to form as soon as tonight or
tomorrow. This system is forecast to meander for the next couple of
days before drifting northward towards the southern coast of Mexico,
and interests there should monitor the progress of this system.
Regardless of development, heavy rain is possible along most of the
coast of southern Mexico and northern Central America throughout
this week.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 7 days...high...70 percent.

Jumped from lemon to cherry in 6 hours - looks like the NHC is taking this seriously after Otis and John, especially with the lack of good observations in this area.

This and basically all models are in excellent agreement.

[zhukm29]

Another interesting thing to note: some of the early models are showing that this system could potentially thread the Isthmus of Tehuantepec into the Gulf of Mexico. This is practically the only way to get a successful EPAC to NATL crossover without dissipation and regeneration, and an incredibly rare event (since almost all crossovers in recorded history are from the NATL to the EPAC). The last time a successful EPAC to NATL crossover happened was TD 11-E in 2010, which developed in the EPAC in this same area, crossed the Isthmus, and eventually strengthened into Tropical Storm Hermine in the Gulf. To go back to the last time a tropical storm made the EPAC to NATL crossover, you would have to go back 101 years to Hurricane Six in 1923, which was a TS that survived the crossover across the Isthmus and eventually became a hurricane in the Gulf.

Coincidentally, the next tropical system that forms in the EPAC will also be designated TD 11-E, the same designation that was given to the last EPAC to NATL crossover system. And an even crazier coincidence - if this system manages to get named and survive the crossover, it would be named Kristy, the only name on this EPAC list that was originally used as an Atlantic name prior to the introduction of the modern naming lists (Kristy was used in 1971, but was also on the NATL list in 1967).

Of course, the chances of this happening are very low, but it would certainly be a pretty crazy event if it did. Another crazy coincidence is that we are also on the K name in the NATL, so if we do end up getting a successful crossover of a named system, we would end up with two storms with the same letter in the same basin - which in and of itself is difficult to attain in separate basins during a normal season without even considering the possibility of a crossover, since the NATL and EPAC typically deviate later in the alphabet, as an active NATL is often correlated to an inactive EPAC, and vice versa. Talk about the stars aligning to produce such a crazy outcome if it actually happens!

[cycloneye]

Tropical Depression Eleven-E Discussion Number 1
NWS National Hurricane Center Miami FL EP112024
300 PM CST Tue Oct 01 2024

The small area of low pressure we have been monitoring for the past
couple of days has become well-defined on satellite imagery this
afternoon and was confirmed with recent scatterometer data. There
has been enough organized deep convection today to consider this a
tropical depression, as suggested by the Data-T estimate from
TAFB, and the initial wind speed is set to 30 kt in accordance with
the max believable scatterometer values.

The initial motion is an uncertain 360/4 kt. The depression has
been moving northward on the eastern end of the monsoon trough, and
this general track is anticipated through landfall with little
change seen in the steering flow for the next day or two. However,
the model guidance is all over the place, owing to differences in
the initial depth of the tropical depression and strength of the
circulation associated with the monsoon trough and Invest 97E. The
ECMWF model seems to have the best representation of the initial
vortex, and the track forecast heavily leans on that model
solution, especially given its recent successes with cyclones in
that area. However, there is considerable spread in the guidance,
and the tropical storm warning is larger than typical based on that
uncertainty.

Northeasterly shear is expected to continue to affect the
depression through landfall, though very warm SSTs and a moist
mid-level environment should promote some strengthening. These
conditions would seem to favor intensification through landfall,
and the first forecast shows a mid-range tropical storm, above most
of the model guidance. At this point, extreme rainfall and flash
flooding seem to be the biggest threats from this system.


KEY MESSAGES:

1. The depression is forecast to become a tropical storm later
tonight or on Wednesday. A Tropical Storm Warning is in effect
for a portion of the coastline of southern Mexico, where tropical
storm conditions are expected to begin on Wednesday.

2. Tropical Depression Eleven-E will likely bring heavy rainfall to
portions of southern Mexico and Guatemala this week. Flooding and
mudslides, especially in areas of steep terrain, are possible,
especially from western Guatemala into portions of the Mexican
states of Chiapas, Oaxaca, Veracruz, and Tabasco.


FORECAST POSITIONS AND MAX WINDS

INIT 01/2100Z 15.1N 94.6W 30 KT 35 MPH
12H 02/0600Z 15.5N 94.6W 35 KT 40 MPH
24H 02/1800Z 15.9N 94.6W 45 KT 50 MPH
36H 03/0600Z 16.5N 94.6W 45 KT 50 MPH...INLAND
48H 03/1800Z 17.1N 94.6W 20 KT 25 MPH...POST-TROP/INLAND
60H 04/0600Z...DISSIPATED

$$
Forecaster Blake

[cycloneye]

BULLETIN
Tropical Depression Eleven-E Advisory Number 2
NWS National Hurricane Center Miami FL EP112024
900 PM CST Tue Oct 01 2024

...DEPRESSION EXPECTED TO PRODUCE HEAVY RAINFALL IN WESTERN
GUATEMALA AND SOUTHEASTERN MEXICO DURING THE NEXT COUPLE OF DAYS...


SUMMARY OF 900 PM CST...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...15.6N 94.6W
ABOUT 55 MI...95 KM SE OF SALINA CRUZ MEXICO
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES

[zhukm29]

TS winds found in the latest ASCAT pass - maybe an upgrade to Kristy soon?

[cycloneye]

Tropical Depression Eleven-E Discussion Number 3
NWS National Hurricane Center Miami FL EP112024
300 AM CST Wed Oct 02 2024

Data from both ASCAT-B and ASCAT-C scatterometers show that the
center of the small circulation is located somewhat west to
west-southwest of the earlier track. There were a couple of
scatterometer vectors showing minimal tropical-storm-force winds,
but these appear to be rain-inflated. The advisory intensity is
kept at 30 kt based on subjective and objective satellite
estimates, and the unimpressive appearance of the system.

With the re-positioning of the estimated center, the motion is
highly uncertain but my best guess is around 290/5 kt. The track
forecast is also quite uncertain, but needs to be shifted westward
from the previous one. The new official forecast is a compromise
between the previous NHC prediction, the trajectory model
forecasts, and the dynamical models which are farther south.

The cyclone continues to have the potential for a little
strengthening before it reaches the coast, although fairly strong
northeasterly vertical wind shear will likely limit its
intensification. The official intensity forecast is near the upper
end of the model guidance. The main impact from this system
is expected to be heavy rainfall, which could lead to flooding and
mudslides over portions of southern Mexico and western Guatemala.


KEY MESSAGES:

1. The depression is forecast to become a tropical storm before it
reaches the coast of southern or southeastern Mexico. Since the
system is now farther west than earlier indicated, the Tropical
Storm Warning has been extended westward along the southern coast
of Mexico.

2. Tropical Depression Eleven-E will likely bring heavy rainfall to
portions of southern Mexico and Guatemala this week. Flooding and
mudslides, especially in areas of steep terrain, are possible,
especially from western Guatemala into portions of the Mexican
states of Chiapas, Oaxaca, Veracruz, and Tabasco.


FORECAST POSITIONS AND MAX WINDS

INIT 02/0900Z 15.4N 95.8W 30 KT 35 MPH
12H 02/1800Z 15.5N 96.0W 35 KT 40 MPH
24H 03/0600Z 15.6N 96.4W 40 KT 45 MPH
36H 03/1800Z 15.7N 97.0W 40 KT 45 MPH
48H 04/0600Z 16.1N 97.5W 30 KT 35 MPH...INLAND
60H 04/1800Z...DISSIPATED

$$
Forecaster Pasch

[cycloneye]

Tropical Depression Eleven-E Discussion Number 4
NWS National Hurricane Center Miami FL EP112024
900 AM CST Wed Oct 02 2024

First light visible imagery and a GMI microwave overpass during the
night show that the center of Tropical Depression Eleven-E is again
a little to the southwest of the previous track. While the system
is part of a large area of convection, the convection is generally
poorly organized, and there has been little change in the various
satellite intensity estimates since the last advisory. Based on
this, the initial intensity remains 30 kt.

The track forecast is of low confidence. Satellite imagery and model
analyses indicate that the depression is currently absorbing or
merging with the vorticity of the EP97 disturbance, and this has
resulted in the system center moving slowly southwestward during the
past 6-12 h. The models have diverse solutions for the subsequent
track, with the GFS and Canadian taking the cyclone northward into
eastern Mexico, while the UKMET forecasts a west-northwestward
motion offshore parallel to the coast and the ECMWF forecasting the
system to dissipate over water. The new forecast track is a
compromise between the the GFS and UKMET forecast and shows the
center making landfall between 36-48 h in the current Tropical Storm
Warning area. This forecast has some significant changes in
direction and speed from the previous forecast, and additional
adjustments may be necessary later today and tonight.

Regardless of exactly where the cyclone tracks, it is expected to
be in an environment of moderate to strong easterly shear through
at least 48 h. This should limit the intensification, and the
forecast peak intensity of 40 kt remains at the upper edge of the
intensity guidance. The main impact from this system is expected
to be heavy rainfall, which could lead to flooding and mudslides
over portions of southern Mexico and western Guatemala.


KEY MESSAGES:

1. The depression is forecast to become a tropical storm before it
reaches the coast of southern or southeastern Mexico. A Tropical
Storm Warning remains in effect for portions of the southern coast
of Mexico.

2. Tropical Depression Eleven-E will likely bring heavy rainfall to
portions of southern Mexico and Guatemala this week. Flooding and
mudslides, especially in areas of steep terrain, are possible,
especially from western Guatemala into portions of the Mexican
states of Chiapas, Oaxaca, Veracruz, Tabasco and coastal Guerrero.


FORECAST POSITIONS AND MAX WINDS

INIT 02/1500Z 14.9N 95.8W 30 KT 35 MPH
12H 03/0000Z 14.8N 96.1W 35 KT 40 MPH
24H 03/1200Z 14.9N 96.6W 40 KT 45 MPH
36H 04/0000Z 15.3N 97.0W 40 KT 45 MPH
48H 04/1200Z 16.0N 97.5W 30 KT 35 MPH...INLAND
60H 05/0000Z 16.4N 98.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 05/1200Z...DISSIPATED

$$
Forecaster Beven

[longhorn2004]

Apparently just a rain maker for Florida, maybe a couple of bands in Texas.

[Pasmorade]

Apparently just a rain maker for Florida, maybe a couple of bands in Texas.

This depression is expected to dissipate in Mexico in a few days. Are you referring to the orange AOI in the Gulf?

[zhukm29]

Here's the latest SAR pass showing winds of 45-50 kts, and a more robust circulation than I would have expected. The NOAA SAR website does have this listed as Kristy (https://www.star.nesdis.noaa.gov/socd/mecb/sar/sarwinds_tropical.php?year=2024&storm=EP112024_KRISTY), but I don't see it elsewhere so I'm not sure if we'll be getting an upgrade at the next advisory.

Storm Name: EP112024 / KRISTY
Storm ID: EP11
Storm Center Longitude: -95.810
Storm Center Latitude: 14.820
Incidence Angle (Degrees): 50.552
Quadrant 1 NE VMax (kts): 45.27
Quadrant 2 SE VMax (kts): 47.28
Quadrant 3 SW VMax (kts): 43.69
Quadrant 4 NW VMax (kts): 45.37
RMax (nmi): 8.00 - 11.00

From the latest model runs, a crossover could still be possible if the vortex is strong enough and moves slightly more east, as a landfall further east would bring it over a path with much lower elevation. Historically, this path through the isthmus was how EPAC to NATL crossovers survived without dissipating over mountainous terrain. Luckily, the gulf does not look to be too conducive for strengthening next week though from the most recent model runs.




The storm certainly does not like to follow the forecast, will be interesting to see how it develops over the coming days.

[cycloneye]

Tropical Depression Eleven-E Discussion Number 7
NWS National Hurricane Center Miami FL EP112024
300 AM CST Thu Oct 03 2024

The depression still has a disheveled satellite appearance, with a
few clusters of deep convection but no clear signs of improved
organization since the previous advisory. This is consistent with
the latest TAFB and SAB Dvorak estimates (T2.0/30-kt), and the
initial intensity remains 30 kt. The center position of the system
is very uncertain given the lack of recent microwave or
scatterometer data. Based on recent fixes, satellite trends, and
earlier scatterometer data, the center has been nudged slightly
north and east of previous estimates. A partial scatterometer pass
shows the depression is likely interacting with a larger trough that
extends northward across the southwestern Gulf of Mexico.

The uncertain initial motion of the system is northeastward at 2 kt.
In general, the global models show a northeastward to northward
motion through Friday while the system approaches and moves across
the coast of southern Mexico within the Tropical Storm Warning area.
Once again, the NHC track forecast has been adjusted eastward based
on the latest guidance. But, the forecast still might require future
adjustments if it is determined that the center is located farther
east than currently estimated.

Significant intensification appears unlikely given the broad,
disorganized convective structure of the depression and continued
northeasterly shear over the system. However, the warm SSTs and
moist environment in which it is embedded could allow for the
depression to become a tropical storm before it reaches the coast of
Mexico, and this is reflected in the NHC intensity forecast.
Regardless, the primary threat remains heavy rainfall that will
continue over portions of southern Mexico for the next day or two.


KEY MESSAGES:

1. The depression is forecast to become a tropical storm before it
reaches the coast of southern Mexico. A Tropical Storm Warning
remains in effect for portions of the southern coast of Mexico.

2. Tropical Depression Eleven-E will likely bring heavy rainfall to
portions of southern Mexico and Guatemala this week. Flooding and
mudslides, especially in areas of steep terrain, are possible,
especially from western Guatemala into portions of the Mexican
states of Chiapas, Oaxaca, Veracruz, Tabasco, and coastal Guerrero.


FORECAST POSITIONS AND MAX WINDS

INIT 03/0900Z 14.5N 95.9W 30 KT 35 MPH
12H 03/1800Z 15.1N 95.7W 35 KT 40 MPH
24H 04/0600Z 16.1N 95.6W 35 KT 40 MPH...INLAND
36H 04/1800Z 17.5N 95.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 05/0600Z...DISSIPATED

$$
Forecaster Reinhart

[zhukm29]

I would be extremely surprised if this system does not get upgraded today, with pretty much all metrics other than SAB/TAFB supporting TS, and ADT already up to 50 kts (which is also supported by yesterday's 45-50kt SAR pass). SAB/TAFB also estimated John as a TD when it was developing an inner core in this area, so I personally think that is underestimating TD11's current intensity. Really underscores the need for more observations in this area - we have a system that will landfall within 48 hours, and we have no idea where the center is, how fast it's moving, or how strong it is because all recent ASCAT and microwave passes have missed. The strength of this system will certainly have downstream implications in the Gulf next week, in addition to those living in the areas that will be affected this week by the storm.

\
UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 9.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 03 OCT 2024 Time : 121020 UTC
Lat : 14:40:30 N Lon : 95:45:03 W


CI# /Pressure/ Vmax
3.3 / 994.5mb/ 51.0kt


Final T# Adj T# Raw T#
3.3 3.3 3.9

Center Temp : -49.0C Cloud Region Temp : -61.1C

[ElectricStorm]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 9.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 03 OCT 2024 Time : 141020 UTC
Lat : 14:48:37 N Lon : 95:42:47 W


CI# /Pressure/ Vmax
3.4 / 993.2mb/ 53.0kt


Final T# Adj T# Raw T#
3.4 3.5 3.9

Either ADT is way off or this should have been named yesterday. But NHC knows what they're doing so I'm guessing this is just wrong

[REDHurricane]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 9.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 03 OCT 2024 Time : 141020 UTC
Lat : 14:48:37 N Lon : 95:42:47 W


CI# /Pressure/ Vmax
3.4 / 993.2mb/ 53.0kt


Final T# Adj T# Raw T#
3.4 3.5 3.9

Either ADT is way off or this should have been named yesterday. But NHC knows what they're doing so I'm guessing this is just wrong

After what just happened with John (and Otis last year) I'm starting to question whether or not the NHC even pays close attention to these EPac systems off the southern coast of Mexico

[Kingarabian]

SAB/TAFB been near 2.0 which is the NHCs basis to keeping this a TD. I agree it should've been named by now though because regardless of satellite estimates, a TD that's been around for 48 hours and has blossoming convection usually has TS force winds somewhere.

[zhukm29]

ADT continues to climb, now at 55 kt

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 9.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 03 OCT 2024 Time : 154020 UTC
Lat : 15:14:47 N Lon : 95:34:27 W


CI# /Pressure/ Vmax
3.5 / 991.7mb/ 55.0kt


Final T# Adj T# Raw T#
3.5 3.8 4.1

Center Temp : -71.1C Cloud Region Temp : -69.4C

[zhukm29]

Looks like this might have just made landfall.