EPAC: EMILIA - Remnants - Discussion

[Subtrop]

EP, 97, 2024080400, , BEST, 0, 157N, 1129W, 25, 1008, DB, 34, NEQ, 0, 0, 0, 0, 1010, 140, 80, 0, 0, E, 0, , 0, 0, INVEST, S, 0, , 0, 0, 0, 0, genesis-num, 016, SPAWNINVEST, ep772024 to ep972024,

https://ftp.nhc.noaa.gov/atcf/btk/bep972024.dat

[floridasun]

EP, 97, 2024080400, , BEST, 0, 157N, 1129W, 25, 1008, DB, 34, NEQ, 0, 0, 0, 0, 1010, 140, 80, 0, 0, E, 0, , 0, 0, INVEST, S, 0, , 0, 0, 0, 0, genesis-num, 016, SPAWNINVEST, ep772024 to ep972024,

https://ftp.nhc.noaa.gov/atcf/btk/bep972024.dat

what that?

[ElectricStorm]

So I guess this might merge with 96E? Will be interesting to see which one becomes dominant

[cycloneye]

Well South of the Baja California Peninsula:
Disorganized showers and thunderstorms located several hundred miles
south-southwest of the southern tip of the Baja California peninsula
are associated with another broad area of low pressure that has
formed. Some development is possible during the next day or two
before the system interacts with the disturbance (EP96) to its
southeast.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...low...20 percent.

[Yellow Evan]

Probably going to be dominant instead of 86E based on 0z GFS and satellite trends.

[cycloneye]

2. South-Southwest of the Baja California Peninsula (EP97):
Shower and thunderstorm activity is showing signs of organization
with an area of low pressure located several hundred miles to the
south-southwest of the southern tip of the Baja California
peninsula. Environmental conditions appear conducive for development
over the next day or two, and a tropical depression is likely to
form during that time while the system meanders within weak steering
currents. Thereafter, the system is forecast to interact with the
disturbance (EP96) to its southeast, which should limit the chances
of further development afterwards.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 7 days...high...70 percent.

[Subtrop]

EP, 05, 2024080412, , BEST, 0, 159N, 1128W, 30, 1007, TD, 34, NEQ, 0, 0, 0, 0, 1010, 140, 100, 0, 0, E, 0, , 0, 0, FIVE, D, 0, , 0, 0, 0, 0, genesis-num, 016, TRANSITIONED, epA72024 to ep052024,

https://www.ssd.noaa.gov/PS/TROP/DATA/A ... 052024.dat

[ElectricStorm]

Tropical Depression Five-E Discussion Number 1
NWS National Hurricane Center Miami FL EP052024
800 AM MST Sun Aug 04 2024

Convection associated with a low located well offshore Mexico has
steadily increased in coverage and organization since yesterday.
Overnight ASCAT and first-light visible imagery indicate that the
cyclone also has a well-defined, if somewhat broad, circulation.
Subjective Dvorak classifications from TAFB and SAB were both 2.0
at 1200 UTC, which support initiating advisories on the system as a
30 kt depression.

The depression is located within a very convectively active
environment over the east Pacific, deep-layer wind shear is low, and
SSTs are plenty warm, so strengthening is expected in the short
term. The biggest source of uncertainty for this forecast is an
expected interaction with a larger disturbance, currently Invest
96E, which is approaching from the east. Based on the available
global and hurricane dynamical model forecasts, the most likely
scenario is that 96E will be the dominant system. In that case, the
new depression will only have a short window to strengthen before it
is wrapped into and dissipates within the other circulation. Models
historically handle interaction cases like this poorly, so
confidence in the forecast is not high, despite the near universal
agreement between the dynamical guidance on this upcoming evolution.

The NHC forecast is very close to the consensus guidance through 24
to 36 h. After that, the model trackers appear to be getting fooled
by the close proximity of 96E and TD Five-E and are following the
stronger vortex instead. The NHC forecast is based heavily on a
broad consensus of model fields beyond 36 h and shows dissipation
occuring by 60 h. There is some chance that the depression could
persist longer than forecast if the two systems remain farther
apart, however there is not enough guidance with a trackable vortex
to justify an explicit forecast beyond what is currently shown.


FORECAST POSITIONS AND MAX WINDS

INIT 04/1500Z 15.8N 112.9W 30 KT 35 MPH
12H 05/0000Z 15.4N 113.0W 35 KT 40 MPH
24H 05/1200Z 14.5N 113.4W 40 KT 45 MPH
36H 06/0000Z 13.8N 113.4W 45 KT 50 MPH
48H 06/1200Z 14.1N 112.8W 45 KT 50 MPH
60H 07/0000Z...DISSIPATED

$$
Forecaster D. Zelinsky

[Kingarabian]

Great banding and very cold tops. Let's see how 96E impacts it.

[Yellow Evan]

GFS and ECMWF now wants 96E to be dominant. Nice structure though - will probably be named soon.

[cycloneye]

[Xpost]

Tropical Depression Five-E Discussion Number 2
NWS National Hurricane Center Miami FL EP052024
200 PM MST Sun Aug 04 2024

The depression has changed little in organization today, as a broad
area of showers and thunderstorms with some modest banding is
present on the western side of the low-level circulation. Subjective
Dvorak intensity estimates and a partial ASCAT-C pass at 1747 UTC
both suggest that the initial intensity remains 30 kt this
afternoon.

The track forecast for TD Five-E is very dependent on a disturbance
to the east of the system (96E), which has a high chance of becoming
a tropical cyclone over the next day or so. Most of the global
models show both of these systems interacting with and rotating
cyclonically around each other. A variety of different model
solutions are depicted, from TD Five-E becoming absorbed by the
larger 96E, to TD Five-E remaining dominant, or a near equal merger
of both systems in the 48-60 h forecast time frame. For this cycle,
the NHC track forecast still shows TD Five-E being absorbed by 96E
and dissipating beyond 48 h, though this is far from certain. It is
possible one of the other two scenarios mentioned above could pan
out. Most of the track guidance due to the interaction initially
show a southward motion that swings rapidly back north or northwest
over the next couple of days before the vortex trackers cannot
distinguish between the two systems. As mentioned this morning
though, dynamical models historically handle interaction cases like
this poorly, so confidence in the track forecast is quite low,
despite the agreement between the dynamical guidance of this binary
interaction.

Until the disturbance to the east starts to interact with TD Five-E,
the environment appears relatively favorable for some
intensification, and the NHC intensity forecast shows strengthening
into a 45 kt tropical storm over the next 24-36 h, prior to the
system's forecast absorption. Note that the interaction of the two
systems also results in a dramatic expansion of the 34-kt wind radii
by 48 h, which should be considered more of the combined wind field
of both features.


FORECAST POSITIONS AND MAX WINDS

INIT 04/2100Z 15.5N 113.2W 30 KT 35 MPH
12H 05/0600Z 14.8N 113.3W 35 KT 40 MPH
24H 05/1800Z 13.9N 113.7W 40 KT 45 MPH
36H 06/0600Z 13.7N 113.4W 45 KT 50 MPH
48H 06/1800Z 15.2N 114.0W 45 KT 50 MPH
60H 07/0600Z...DISSIPATED

$$
Forecaster Papin
[/Xpost]

[cycloneye]

Hello Emilia.

Tropical Storm Emilia Discussion Number 3
NWS National Hurricane Center Miami FL EP052024
800 PM MST Sun Aug 04 2024

The organization of the tropical cyclone has improved on satellite
imagery since the previous advisory. The subjective CI numbers from
TAFB and SAB are both T-2.5/35 kt, and the CIMSS objective intensity
estimates range from 33 to 35 kt. Earlier ASCAT data from around 17
UTC had peak wind vectors of 31 kt, and the organization on
satellite imagery has certainty improved since that time, with the
cyclone becoming more compact. Based on the Dvorak estimates, the
depression is upgraded to Tropical Storm Emilia with an initial
intensity of 35 kt.

The track forecast for Emilia is very dependent on a disturbance to
the east of the system (Invest 96E), which has a high chance of
becoming a tropical cyclone over the next day or so. Most of the
global models show both systems interacting with and rotating
cyclonically around each other. Emilia should move to the
south-southwest for the next 24 h, while it is located to the west
of 96E. After that time, the larger circulation of 96E should pull
the smaller Emilia toward the northwest or north-northwest. Only
minor changes were made to the previous NHC track forecast. 96E
and Emilia should merge together into one cyclone over the next
couple of days, but it is uncertain which cyclone will be dominant
and which cyclone will be absorbed. This forecast assumes that 96E
will absorb Emilia, with Emilia dissipating beyond 48 h. However,
it is quite possible that the opposite occurs, with Emilia absorbing
96E. Either way, I expect a tropical cyclone (the merged system) to
be moving west-northwestward in 3 to 4 days, spreading tropical
storm conditions across the open waters of the Pacific. The ECMWF
model shows the two systems merging in 36-48 h, but the latest GFS
model predicts a longer binary interaction, with the merger
occurring in 3 to 4 days.

Until the disturbance to the east starts to interact with Emilia,
the environment appears favorable for intensification, and the
intensity guidance has trended upward this cycle. The new NHC
forecast shows Emilia strengthening to a 55 kt tropical storm in 36
h. This is near, or slightly below the middle of the intensity
guidance envelope. The thinking is that Emilia will merge with 96E
after that time, and 96E will likely be a tropical storm at the
time of the merger.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0300Z 15.0N 113.2W 35 KT 40 MPH
12H 05/1200Z 14.2N 113.4W 40 KT 45 MPH
24H 06/0000Z 13.8N 113.5W 50 KT 60 MPH
36H 06/1200Z 14.3N 113.8W 55 KT 65 MPH
48H 07/0000Z 15.6N 114.8W 55 KT 65 MPH
60H 07/1200Z...DISSIPATED

$$
Forecaster Hagen/Roberts

[lilbump3000]

[kala]

There is a distinct chance we see an equal Fujiwara merger of two tropical storms here with 96E...

Anyone know when the last time that happened was (worldwide)? Is it Pat and Ruth?

I guess Vernon and MTS 08 were close, but not sure if that quite reaches the threshold to count...

Ultimately though, I think Emilia will dominate.

[cycloneye]

Tropical Storm Emilia Discussion Number 4
NWS National Hurricane Center Miami FL EP052024
200 AM MST Mon Aug 05 2024

Emilia has held relatively steady overnight. Recently, a large
burst of convection with cloud top temperatures of less than -80
degrees C has formed near the estimated center. Subjective Dvorak
estimates from TAFB and SAB both support maintaining the initial
intensity at 35 kt for this advisory cycle.

The intensity forecast continues to be quite uncertain. This is
because of a system to the east of Emilia, Invest 96E. Almost all
global and regional weather model guidance has trended toward making
Emilia the dominant system. As a result, dissipation is no longer
expected in a couple of days. Instead, Emilia is expected to take
advantage of the warm ocean waters and conducive environment and
strengthen through mid-week. By the end of the week, Emilia should
move into a more stable environment with cooling sea surface
temperature and gradually weaken. However, it is still possible
that Invest 96E forms, strengthens, and causes Emilia to dissipate
sooner. The latest NHC intensity forecast peaks Emilia in 48 h at
60 kt and predicts the system to become a remnant low by 120 h.

The tropical storm is moving slowly to the south-southwest, at an
estimated 200/4 kt. The near-term track forecast is being
influenced by Invest 96E. Emilia is forecast to continue slowly
south-southwestward as the two systems rotate cyclonically around
each other. In about a day or so, Emilia should begin to lift to
the north-northwest and accelerate as it is steered by a ridge
centered over the southwestern United States. This motion should
gradually turn more northwestward by mid-week. The latest track
forecast has shifted to the west due to the initial location and has
been extended into the future out to 5 days.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0900Z 14.8N 114.1W 35 KT 40 MPH
12H 05/1800Z 14.3N 114.2W 40 KT 45 MPH
24H 06/0600Z 14.3N 114.5W 50 KT 60 MPH
36H 06/1800Z 15.3N 115.1W 55 KT 65 MPH
48H 07/0600Z 16.4N 116.4W 60 KT 70 MPH
60H 07/1800Z 17.9N 118.3W 55 KT 65 MPH
72H 08/0600Z 19.3N 120.9W 45 KT 50 MPH
96H 09/0600Z 21.6N 125.9W 35 KT 40 MPH
120H 10/0600Z 23.1N 131.0W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Bucci

[cycloneye]

Tropical Storm Emilia Discussion Number 5
NWS National Hurricane Center Miami FL EP052024
800 AM MST Mon Aug 05 2024

Satellite imagery shows that Emilia remains a sheared cyclone this
morning, with the low-level center located near the northeastern
edge of a large convective mass with cloud tops to near -85C. The
various subjective and objective satellite intensity estimates have
nudged upward to the 35-40 kt range, and the initial intensity is
set at 40 kt.

The latest global model runs continue to suggest that Emilia will be
the survivor in interaction with the newly formed Tropical Storm
Fabio to the east, and the intensity forecast is based on this
scenario and the expectation of continued moderate easterly shear.
The forecast follows the trend of the intensity guidance and
forecasts a peak intensity of 60 kt in 48 h. After that time,
Emilia is expected to slowly weaken as it moves over decreasing sea
surface temperatures. The new forecast is basically an update of
the previous forecast. It should be noted that this forecast is low
confidence due to the possibility that Fabio might still end up as
the dominant cyclone.

Interaction with Fabio should steer Emilia south-southwestward to
southward for the next 12 h or so. After that, a turn toward the
northwest or north-northwest with an increase in forward speed is
expected as Emilia start to absorb Fabio. After Fabio dissipates in
about 60 h, Emilia should generally move west-northwestward on the
south side of a low- to mid-level ridge to the north. The first 96
h of the forecast track have been adjusted somewhat based on the GFS
and Canadian model forecasts of the interaction between Emilia and
Fabio.


FORECAST POSITIONS AND MAX WINDS

INIT 05/1500Z 14.5N 114.1W 40 KT 45 MPH
12H 06/0000Z 13.9N 114.2W 45 KT 50 MPH
24H 06/1200Z 14.4N 114.8W 50 KT 60 MPH
36H 07/0000Z 15.9N 115.4W 55 KT 65 MPH
48H 07/1200Z 18.2N 117.1W 60 KT 70 MPH
60H 08/0000Z 19.6N 119.7W 55 KT 65 MPH
72H 08/1200Z 20.8N 122.6W 45 KT 50 MPH
96H 09/1200Z 22.5N 127.5W 35 KT 40 MPH
120H 10/1200Z 23.5N 132.5W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven

[cycloneye]

Tropical Storm Emilia Discussion Number 6
NWS National Hurricane Center Miami FL EP052024
200 PM MST Mon Aug 05 2024

Satellite imagery shows that Emilia remains a sheared cyclone this
afternoon, with the low-level center still located near the
northeastern edge of a large convective mass with cloud tops to
near -80C. A recent ASCAT overpass showed winds of 40+ kt in the
southern semicircle, while the various subjective and objective
satellite intensity estimates remain in the 35-40 kt range. Based
on the scatterometer data, the initial intensity is increased to
45 kt. The initial wind radii were adjusted based on the ASCAT
data.

The latest global model runs continue to forecast that Emilia will
be the survivor in its interaction with the Tropical Storm Fabio to
the east, and the intensity forecast is based on this scenario and
the expectation of continued moderate easterly shear. The forecast
follows the trend of the intensity guidance and now forecasts a
peak intensity of 55 kt in 36 h. After that time, although the
shear is forecast to decrease, Emilia is expected to slowly weaken
as it moves over decreasing sea surface temperatures. The new
forecast is again an update of the previous forecast. Confidence
in this forecast is increasing due to the more consistent model
guidance that Emilia will absorb Fabio and not the other way around.

The interaction with Fabio should steer Emilia southward for the
next 12 h or so. After that, a turn toward the northwest or
north-northwest with an increase in forward speed is expected as
Emilia starts to absorb Fabio. After Fabio dissipates in about 48
h, Emilia should generally move west-northwestward on the south
side of a low- to mid-level ridge to the north, with this general
motion expected for the remainder of the forecast period. The new
forecast track has only minor changes from the previous track.


FORECAST POSITIONS AND MAX WINDS

INIT 05/2100Z 13.6N 114.0W 45 KT 50 MPH
12H 06/0600Z 13.3N 114.1W 45 KT 50 MPH
24H 06/1800Z 14.3N 114.3W 50 KT 60 MPH
36H 07/0600Z 16.5N 115.5W 55 KT 65 MPH
48H 07/1800Z 18.7N 117.8W 55 KT 65 MPH
60H 08/0600Z 19.8N 120.6W 50 KT 60 MPH
72H 08/1800Z 20.6N 123.1W 40 KT 45 MPH
96H 09/1800Z 22.0N 127.5W 30 KT 35 MPH
120H 10/1800Z 23.5N 133.0W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven

[cycloneye]

Tropical Storm Emilia Discussion Number 7
NWS National Hurricane Center Miami FL EP052024
800 PM MST Mon Aug 05 2024

Earlier ASCAT data showed that Emilia was likely a 45 kt tropical
storm around 18Z, with an exposed low-level center located just
outside of and to the northeast of the convective overcast area,
due to moderate northeasterly shear. Since that time, the
low-level center appears to have moved toward the edge of the
convective mass. However infrared satellite imagery shows that some
of the cloud tops in the convective area have warmed slightly during
that time. The latest subjective Dvorak estimates are 45 kt from
TAFB and 35 kt from SAB. Recent objective intensity estimates from
CIMSS range from 34 to 42 kt. Based on all the data and satellite
imagery, the 45 kt intensity is unchanged from the previous NHC
advisory.

The latest global model runs continue to forecast that Emilia will
be the survivor in its interaction with Tropical Storm Fabio to the
east, and the merger is forecast to happen on Wednesday or Wednesday
night. In the short term, moderate northeasterly shear is forecast
to continue over Emilia. Due to the moderate shear, only modest
strengthening is forecast, and no change is made to the previous NHC
peak intensity forecast of 55 kt. After Emilia absorbs Fabio in
about 48 h, Emilia is forecast to move over less than 26C SSTs,
which should cause weakening. Emilia is forecast to weaken below
tropical storm strength by day 4, and will continue to spin down
after that as it moves over progressively colder water. Confidence
in this forecast is increasing due to the more consistent model
guidance that Emilia will absorb Fabio and not the other way around.

Emilia is currently moving very slowly toward the west-southwest.
A turn toward the northwest or north-northwest with an increase in
forward speed is expected Tuesday, and Emilia is expected to absorb
Fabio on Wednesday. After Fabio dissipates in about 48 h, Emilia
should generally move west-northwestward on the south side of a low-
to mid-level ridge to the north, with this general motion expected
for the remainder of the forecast period. Only very minor changes
were made to the previous NHC track forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 06/0300Z 13.8N 114.3W 45 KT 50 MPH
12H 06/1200Z 14.0N 114.5W 50 KT 60 MPH
24H 07/0000Z 15.5N 115.4W 55 KT 65 MPH
36H 07/1200Z 17.5N 117.1W 55 KT 65 MPH
48H 08/0000Z 19.2N 119.4W 50 KT 60 MPH
60H 08/1200Z 20.2N 122.1W 45 KT 50 MPH
72H 09/0000Z 21.0N 124.4W 35 KT 40 MPH
96H 10/0000Z 22.4N 129.0W 30 KT 35 MPH
120H 11/0000Z 23.5N 134.0W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Hagen

[cycloneye]

Tropical Storm Emilia Discussion Number 8
NWS National Hurricane Center Miami FL EP052024
200 AM MST Tue Aug 06 2024

Emilia is becoming more organized overnight. The tropical storm has
had a healthy burst of deep convection near the surface center with
a growing central dense overcast. Some fortuitous scatterometer
data showed an area of 45-50 kt of wind along the southern portion
of the circulation. This combined with a TAFB Dvorak estimate of
T3.5 is the basis for increasing the initial intensity to 55 kt for
this advisory. The wind radii have also been updated using the
satellite surface wind data, extending the tropical-storm-force
winds in the southern half of the storm.

The cyclone is moving at an uncertain 255/4 kt. Emilia's track
forecast is dependent on Fabio, the tropical storm to its east. The
two systems are forecast to rotate around one another as they both
turn generally north-northwestward to northwestward and accelerate
along southwestern side of a ridge centered over the United States
during the next day or so. As Emilia weakens later in the week,
the shallower vortex should turn westward in the low-level flow.
Only small changes have been made to the latest track forecast, and
it lies on the southern side of the track guidance envelope.

Models continue to show Emilia as the dominant cyclone that should
survive the interaction with Fabio. Steady intensification is still
forecast over the next 24 h, but the peak has been adjusted upward
due to the recent strengthening trend. Emilia is now expected to
become a hurricane on Wednesday. Later in the week, most models
show Emilia and Fabio merging, though the timing is questionable.
The official prediction shows Fabio being absorbed into Emilia's
circulation by 48 h, similar to the most recent ECMWF model
forecast. The storm will gradually weaken into a remnant low by
the end of the forecast period as it moves over cooling ocean waters
and into a dry and stable environment. Due to the uncertainty in
the interaction with Tropical Storm Fabio, changes to the forecast
could be necessary in later advisory packages.


FORECAST POSITIONS AND MAX WINDS

INIT 06/0900Z 13.7N 114.7W 55 KT 65 MPH
12H 06/1800Z 14.3N 115.1W 60 KT 70 MPH
24H 07/0600Z 16.0N 116.2W 65 KT 75 MPH
36H 07/1800Z 18.1N 118.1W 60 KT 70 MPH
48H 08/0600Z 19.6N 120.6W 50 KT 60 MPH
60H 08/1800Z 20.8N 123.0W 45 KT 50 MPH
72H 09/0600Z 21.5N 125.5W 35 KT 40 MPH
96H 10/0600Z 22.8N 130.4W 30 KT 35 MPH
120H 11/0600Z 23.7N 135.0W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Bucci

[HurricaneEnzo]

Fugeewahruh. Looks like Emilia is going to win the battle.