EPAC: EUGENE - Post-Tropical - Discussion

[Sciencerocks]

[Yellow Evan]

TXPZ22 KNES 051231
TCSENP

A. TROPICAL DISTURBANCE (97E)

B. 05/1200Z

C. 17.4N

D. 105.3W

E. FIVE/GOES-W

F. T1.5/1.5

G. IR/EIR/SWIR

H. REMARKS...3/10 BANDING RESULTS IN A DT OF 1.5. THE MET IS 1.0 AND
THE PT IS 1.5. THE FT IS BASED ON THE DT.

I. ADDL POSITIONS

NIL


...BROWN

[cycloneye]

TCDEP1

Tropical Depression Six-E Discussion Number 1
NWS National Hurricane Center Miami FL EP062023
900 AM MDT Sat Aug 05 2023

During the past several hours, the area of low pressure the National
Hurricane Center has been monitoring offshore the southwestern coast
of Mexico has gradually become better organized on GOES-18 satellite
imagery. Additionally, overnight microwave images indicated
improved curved banding over the south and east portions of the
cyclone. Based on the overall improvement of the system's cloud
pattern and Dvorak intensity estimates from both TAFB and SAB
yielding an initial intensity of 30 kt, advisories are being
initiated on Tropical Depression Six-E.

Modest strengthening is expected during the next 36 hours or so
while the cyclone remains over warm oceanic surface temperatures;
however, moderate northeasterly shear is impinging on the north
semicircle of the system. By early next week, the depression
should weaken rather quickly as it traverses a sharp decreasing sea
surface temperature gradient and moves into a more stable air mass.
The official forecast is based on a compromise of the HFIP, HCCA,
and the IVCN intensity models. The majority of the guidance,
including the global models, indicates the cyclone degenerating to
a remnant low in 3 days, if not sooner.

The initial motion is somewhat uncertain but is estimated to be
northwestward or 310/12 kt. The depression is located south of a
subtropical ridge extending from the Southern Plains of the United
States to the Baja California peninsula and eastern Pacific offshore
waters. This mid-level ridge should steer the cyclone toward the
northwest during the next day or so. Afterward, global models show
the western portion of the ridge eroding in response to a major
shortwave trough approaching the west coast of the United States.
As a result, the depression should turn toward the west-northwest
with a gradual reduction in forward speed early next week. The NHC
track forecast lies near the HCCA and TVCE multi-model aids and
between the GFS and ECMWF global models. Although the track
forecast is currently off the southwestern coast of Mexico, enough
uncertainty still exists that interests in the southern portion of
the Baja California peninsula should monitor the progress of this
system.


FORECAST POSITIONS AND MAX WINDS

INIT 05/1500Z 18.2N 106.8W 30 KT 35 MPH
12H 06/0000Z 19.4N 108.3W 35 KT 40 MPH
24H 06/1200Z 21.0N 110.8W 45 KT 50 MPH
36H 07/0000Z 22.2N 113.7W 50 KT 60 MPH
48H 07/1200Z 23.4N 116.8W 40 KT 45 MPH
60H 08/0000Z 24.4N 119.4W 30 KT 35 MPH
72H 08/1200Z 25.0N 121.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 09/1200Z 25.6N 122.3W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 10/1200Z...DISSIPATED

$$
Forecaster Roberts

[Kingarabian]

GFS has really backed off. Was making this a borderline Cat.5 at one point.

[Sciencerocks]

 https://twitter.com/VortixWx/status/1687837901902503936

[Sciencerocks]

 https://twitter.com/zoom_earth/status/1687858086290288646

[cycloneye]

Hello Eugene.

EP, 06, 2023080518, , BEST, 0, 188N, 1073W, 35, 1004, TS

[Sciencerocks]

[Yellow Evan]

TXPZ22 KNES 051840
TCSENP

A. 06E (NONAME)

B. 05/1800Z

C. 18.7N

D. 107.0W

E. THREE/GOES-W

F. T2.0/2.0

G. IR/EIR/VIS

H. REMARKS...6/10 BANDING RESULTS IN A DT OF 3.0. UPR-LVL OUTFLOW GOOD
E-S QUAD AND POOR N-W QUADS. MET=1.5 AND PT=2.0. FT BASED ON PT DUE TO
IRREG CONVECTION. SYSTEM MAY BE A BIT STRONGER THAN FT INDICATES.

I. ADDL POSITIONS

NIL


...KONON

What is this PT rationale?

[Yellow Evan]

Great structure.

[Ntxw]

Maybe RI? Very least should have Eugene.

[ElectricStorm]

000
WTPZ31 KNHC 052036
TCPEP1

BULLETIN
Tropical Storm Eugene Advisory Number 2
NWS National Hurricane Center Miami FL EP062023
300 PM MDT Sat Aug 05 2023

...DEPRESSION BECOMES THE FIFTH TROPICAL STORM OF THE EASTERN
NORTH PACIFIC HURRICANE SEASON...


SUMMARY OF 300 PM MDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...19.2N 107.7W
ABOUT 290 MI...470 KM SSE OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...NW OR 315 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

Interests in the southern portion of the Baja California peninsula
should monitor the progress of this system.


DISCUSSION AND OUTLOOK
----------------------
At 300 PM MDT (2100 UTC), the center of Tropical Storm Eugene was
located near latitude 19.2 North, longitude 107.7 West. Eugene is
moving toward the northwest near 15 mph (24 km/h), and this motion
should continue through the weekend followed by a turn toward the
west-northwest early next week.

Maximum sustained winds are near 40 mph (65 km/h) with higher gusts.
Some further strengthening is forecast during the next couple of
days. Afterward, weakening is expected and the cyclone should
quickly become a remnant low in 3 days.

Tropical-storm-force winds extend outward up to 45 miles (75 km)
from the center.

The estimated minimum central pressure is 1004 mb (29.65 inches).


HAZARDS AFFECTING LAND
----------------------
RAINFALL: Heavy rainfall associated with Eugene will remain mostly
off the southwest Mexican coast. The outer edges of rainfall from
the depression may produce 1 to 2 inches of rain along the coastal
sections of the southwestern Mexican states of Colima, Jalisco,
Nayarit and the southern portion of Baja California Sur.


NEXT ADVISORY
-------------
Next complete advisory at 900 PM MDT.

$$
Forecaster Roberts

[Sciencerocks]

 https://twitter.com/VortixWx/status/1687949947226755072




I'd say 50 knots

[cycloneye]

45 kt.

EP, 06, 2023080600, , BEST, 0, 196N, 1083W, 45, 1000, TS

[Sciencerocks]

[cycloneye]

Tropical Storm Eugene Discussion Number 3
NWS National Hurricane Center Miami FL EP062023
900 PM MDT Sat Aug 05 2023

Eugene has strengthened this evening. Deep convection has increased
near and over the center of the system during the past several
hours, with more pronounced convective banding over the southeastern
portion of the circulation. Additionally, earlier AMSR2 and SSMIS
passive microwave data showed some evidence of a formative inner
core trying to take shape. The various 00 UTC objective and
subjective satellite intensity estimates ranged from 35-55 kt. Given
the overall improved convective structure of Eugene, the initial
intensity is raised to 45 kt based on a blend of these data.

The tropical storm has a brief window to intensity over very warm
(29-30C) SSTs before the environment becomes increasingly hostile.
Deep-layer shear is forecast to strengthen later on Sunday, and soon
thereafter Eugene will encounter a drier and more stable airmass
while moving over progressively cooler SSTs. The updated NHC
intensity forecast shows a slightly higher peak (55 kt) in 12-24 h
that is supported by the latest intensity consensus aids, followed
by steady weakening through early next week. Eugene could become
completely devoid of convection in 60 h based on simulated satellite
imagery from the global and hurricane models. Therefore, the NHC
forecast shows Eugene degenerating to a remnant low early Tuesday
and dissipating by the end of the forecast period.

The initial motion remains northwestward at 310/13 kt. Eugene is
expected to turn west-northwestward over the next day or two while
being steered by a mid-level ridge to its north. Later in the
forecast period, a shortwave trough approaching the U.S. West Coast
will produce a break in the subtropical ridge. This will result in
weaker steering currents that should cause the shallow cyclone to
slow down before eventually turning more northward and dissipating
over cooler waters. The updated NHC forecast shows a slightly faster
forward speed in agreement with the latest HCCA and TVCE aids, but
otherwise is very similar to the previous issuance. While the risk
of tropical-storm-force winds for the southern portion of the Baja
California peninsula remains low based on this forecast, interests
there should continue to monitor the progress of this system.


FORECAST POSITIONS AND MAX WINDS

INIT 06/0300Z 20.0N 108.8W 45 KT 50 MPH
12H 06/1200Z 21.4N 110.8W 55 KT 65 MPH
24H 07/0000Z 22.8N 113.7W 55 KT 65 MPH
36H 07/1200Z 24.1N 116.9W 45 KT 50 MPH
48H 08/0000Z 25.2N 119.5W 35 KT 40 MPH
60H 08/1200Z 26.0N 121.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 09/0000Z 26.7N 121.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 10/0000Z 28.4N 120.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 11/0000Z...DISSIPATED

$$
Forecaster Reinhart

[Extratropical94]

Forecast peak raised to 65kts

Tropical Storm Eugene Discussion Number 4
NWS National Hurricane Center Miami FL EP062023
300 AM MDT Sun Aug 06 2023

Eugene continues to steadily strengthen. An ASCAT-C pass from a few
hours ago showed peak winds around 50 kt, and the initial intensity
is increased to 55 kt since that instrument often is unable to
resolve the peak winds. This intensity value is higher than the
current satellite intensity estimates. The cloud pattern of Eugene
resembles a central dense overcast with the deepest convection near
the estimated center. Eugene is about 120 n mi south of Cabo San
Lucas and it could get a little closer to that area later this
morning before pulling away late today. It should be noted that
Eugene is a relatively small tropical storm, with its 34-kt wind
radii currently extending no more than 60 n mi from the center.

The storm continues to move northwestward, or 315 degrees, at about
12 kt. Eugene should turn to the west-northwest later today and
continue in that direction through Monday as it moves in the flow on
the south side of a fairly strong mid-level ridge. By early
Tuesday, however, the western portion of the ridge is expected to
erode due to an approaching shortwave trough. In response, Eugene
is forecast to slow down and turn northward or northeastward during
the middle part of the week. The NHC track forecast is similar to
the previous one and lies near the northern edge of the model
guidance in the short term, in best agreement with the HCCA model.

Since Eugene will be over warm waters for another 12 hours or so,
continued strengthening is forecast, and Eugene is now predicted to
become a hurricane later today. However, by tonight, the system
will be moving over progressively cooler waters and into a drier air
mass, which should end the strengthening trend and promote a steady
decay. The NHC intensity forecast is a little higher than the
previous one during the next couple of days, but falls in line with
the old forecast after that. Eugene is still expected to become a
remnant low over cool 20 degree C waters in about 60 hours and
dissipate in 4 to 5 days.

Eugene will likely produce areas of heavy rains and gusty winds
across southern portions of the Baja California Sur today as it
passes to the south of the peninsula. Interests there should
monitor the progress of this system.


FORECAST POSITIONS AND MAX WINDS

INIT 06/0900Z 20.9N 109.9W 55 KT 65 MPH
12H 06/1800Z 22.2N 112.0W 65 KT 75 MPH
24H 07/0600Z 23.3N 115.1W 60 KT 70 MPH
36H 07/1800Z 24.4N 118.0W 50 KT 60 MPH
48H 08/0600Z 25.3N 120.4W 40 KT 45 MPH
60H 08/1800Z 26.3N 121.3W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 09/0600Z 27.1N 121.4W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 10/0600Z 29.1N 119.6W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 11/0600Z...DISSIPATED

$$
Forecaster Cangialosi

[Sciencerocks]

[Yellow Evan]

Chou 2013 supports making Eugene a hurricane if peak was 52 knots on ASCAT fwiw.

[Yellow Evan]

Probably qualifies as a T4.0 based on banding too.