EPAC: FOURTEEN-E - Remnants - Discussion

[Extratropical94]

Finally an invest

EP, 97, 2023092218, , BEST, 0, 125N, 1140W, 25, 1009, DB, 34, NEQ, 0, 0, 0, 0, 1010, 100, 50, 0, 0, E, 0, , 0, 0, INVEST, S, 0, , 0, 0, 0, 0, genesis-num, 022, SPAWNINVEST, ep742023 to ep972023,

Central East Pacific:
Showers and thunderstorms associated with a tropical wave located
several hundred miles south of the southern tip of the Baja
California peninsula continue to show signs of organization. Further
development of the disturbance is likely, and a tropical depression
is expected to form over the weekend or early next week while the
system moves generally westward across the central and western parts
of the eastern Pacific basin.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 7 days...high...80 percent.

[Kingarabian]

Models were enthusiastic about this one a few days ago. Not so much anymore. It will be moving generally west so it could have a chance at more significant development.

[Sciencerocks]

[WalterWhite]

The GFS, ECMWF, CMC, and ICON are all extremely bearish with this system. This will at most become a low-end tropical storm.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Fri Sep 22 2023

For the eastern North Pacific...east of 140 degrees west longitude:

1. Central East Pacific (EP97):
Showers and thunderstorms associated with a tropical wave located
several hundred miles south-southwest of the southern tip of the
Baja California peninsula continue to show signs of organization.
Further development of the disturbance is likely, and a tropical
depression is expected to form this weekend or early next week while
the system moves generally westward across the central and western
parts of the eastern Pacific basin.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 7 days...high...80 percent.

Forecaster Bucci

[Sciencerocks]

[Sciencerocks]

[Hurricane2022]

some rapid and unexpected changes are happening now. 97E is probably a tropical storm.

[galaxy401]

I think a special advisory is needed even if there is no threat to land.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Sat Sep 23 2023

For the eastern North Pacific...east of 140 degrees west longitude:

1. Central East Pacific (EP97):
An area of low pressure is located several hundred miles southwest
of the southern tip of the Baja California peninsula. Recent
microwave imagery indicates that showers and thunderstorms
associated with this system have become better organized, though it
remains unclear if a well-defined surface circulation has formed.
Regardless, further development of this system is anticipated and a
tropical depression is likely to form during the next couple of
days. The system is moving westward at 15 to 20 mph, and this
general motion is expected to continue for the next several days.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 7 days...high...80 percent.

Forecaster D. Zelinsky/Papin

[Teban54]

Looks better than TD17 in the Atlantic at the moment.

[Sciencerocks]

This is probably a tropical storm. I'd say 35-40 knts.

[Sciencerocks]

[cycloneye]

Tropical Depression Fourteen-E Discussion Number 1
NWS National Hurricane Center Miami FL EP142023
1100 AM HST Sat Sep 23 2023

An area of disturbed weather located well southwest of the southern
tip of the Baja California peninsula became rapidly better organized
this morning. SSMIS microwave imagery at 1427 UTC showed that deep
convection had organized into a very well-defined band, with what
appeared to be a developing low-level center just to the north of
the convection. Since then, 1-minute visible GOES-18 has been very
helpful in confirming the development of a well-defined surface
circulation. Therefore, advisories have been initiated on Tropical
Depression Fourteen-E. The initial maximum sustained wind estimate
is highly uncertain, but is based on a 30 kt Dvorak current
intensity analysis from TAFB.

The depression appears to be quite small, and is therefore not being
well-resolved by most global models. The center of the cyclone
appears to be just north of a tight band of deep convection. Its
small size and an expected moderate shear environment could make the
cyclone susceptible to rapid changes in intensity that are difficult
to anticipate. The NHC intensity forecast is a little higher than
the model consensus for the next 48 h, most similar to the DSHP
model, but still shows only slight strengthening during that time
frame. After about 72 h, wind shear is expected to increase quickly,
which should cause the small cyclone to weaken. The system is
subsequently expected to dissipate into a trough after about 4 days.

The initial motion estimate is west at 12 kt. An extensive ridge
extending over most of the eastern North Pacific should keep the
depression on a similar heading for the next 4 days until the system
dissipates. Although the strength of the depression does not appear
to be captured well by the global models, they do appear to have
very reasonable track forecasts that are in good agreement with one
another. The initial NHC track forecast is near the middle of the
average-spread guidance envelope.

FORECAST POSITIONS AND MAX WINDS

INIT 23/2100Z 13.9N 120.4W 30 KT 35 MPH
12H 24/0600Z 14.3N 122.4W 35 KT 40 MPH
24H 24/1800Z 14.7N 125.2W 40 KT 45 MPH
36H 25/0600Z 14.9N 127.7W 40 KT 45 MPH
48H 25/1800Z 14.9N 130.5W 45 KT 50 MPH
60H 26/0600Z 14.6N 133.3W 40 KT 45 MPH
72H 26/1800Z 14.3N 136.5W 35 KT 40 MPH
96H 27/1800Z 14.0N 142.5W 30 KT 35 MPH
120H 28/1800Z...DISSIPATED

$$
Forecaster D. Zelinsky

[Sciencerocks]

[cycloneye]

Tropical Depression Fourteen-E Discussion Number 2
NWS National Hurricane Center Miami FL EP142023
500 PM HST Sat Sep 23 2023

The depression has changed little since the last advisory. Deep
convection, with cold cloud tops below -80 degree C, have been
forming near the estimated low-level center for the past several
hours. Microwave imagery still shows a curved band in the southern
portion of the circulation. The initial intensity is held at 30 kt,
closest to the TAFB Dvorak classification.

Current atmospheric and oceanic conditions suggest the depression
could strengthen during the next several days. The majority of the
guidance shows gradual strengthening, even with a low-to-moderate
vertical wind shear environment. As mentioned previously though,
global models do not appear to be capturing the initial state of
this system well, making the short-term forecast slightly less
certain. By day 2, the upper-level winds are expected to increase
through the end of the forecast period which should limit
intensification. At 96 h, the cyclone should move into an area of
higher wind shear and dry mid-level relative humidities which are
expected to weaken the system into a post-tropical remnant low, and
then open into a trough by day 5.

The depression is moving westward at 13 kt. A mid-level ridge
centered over central Mexico should keep the cyclone on a general
westward trajectory through the entire forecast period. The latest
NHC track forecast shifted slightly south of the previous forecast
and lies just north of the various consensus aids.


FORECAST POSITIONS AND MAX WINDS

INIT 24/0300Z 13.9N 121.7W 30 KT 35 MPH
12H 24/1200Z 14.3N 123.9W 35 KT 40 MPH
24H 25/0000Z 14.5N 126.6W 40 KT 45 MPH
36H 25/1200Z 14.5N 129.1W 40 KT 45 MPH
48H 26/0000Z 14.4N 131.7W 40 KT 45 MPH
60H 26/1200Z 14.0N 134.6W 40 KT 45 MPH
72H 27/0000Z 13.6N 137.7W 35 KT 40 MPH
96H 28/0000Z 13.1N 144.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 29/0000Z...DISSIPATED

$$
Forecaster Bucci

[cycloneye]

Tropical Depression Fourteen-E Discussion Number 3
NWS National Hurricane Center Miami FL EP142023
1100 PM HST Sat Sep 23 2023

The cyclone has not become significantly better organized over the
past several hours. Deep convection has been waxing and waning
near the estimated center and the system lacks distinct convective
banding features. Upper-level outflow is not very well defined at
this time. The current intensity estimate is held at 30 kt based
on Dvorak analyses from TAFB and SAB. Objective intensity
estimates from UW-CIMSS are a little higher, suggesting that the
cyclone may be a minimal tropical storm. However it is prudent to
wait for additional intensity estimates before upgrading the system.

Although the center fixes have some scatter, my best estimate of
initial motion is westward, or 280/12 kt. A mid-level ridge to the
north of the system should maintain a generally westward track for
the next couple of days. The track model consensus shows a
slightly south of westward motion in the latter part of the forecast
period, Thus the official forecast has been nudged a little south of
the previous one in 2-4 days, but not as far south as the consensus
prediction.

Over the next day or so, the depression should remain over warm
waters and in an atmospheric environment of moderate vertical wind
shear with marginally moist mid-level humidities. Therefore some
modest short-term strengthening is predicted. Around 48 hours and
beyond, southwesterly shear should increase and this, along with
some drier air, is likely to halt the intensification process. The
system is likely to gradually weaken in 2 to 4 days and, in fact,
the global models show the system degenerating into a trough within
4 days. The official forecast, like the previous one, shows the
system becoming a remnant low in 96 hours. However it is possible
that the cyclone may not last as long as that.


FORECAST POSITIONS AND MAX WINDS

INIT 24/0900Z 14.3N 122.4W 30 KT 35 MPH
12H 24/1800Z 14.6N 124.4W 35 KT 40 MPH
24H 25/0600Z 14.7N 126.9W 40 KT 45 MPH
36H 25/1800Z 14.6N 129.3W 40 KT 45 MPH
48H 26/0600Z 14.2N 132.0W 35 KT 40 MPH
60H 26/1800Z 13.6N 135.0W 35 KT 40 MPH
72H 27/0600Z 13.0N 138.0W 30 KT 35 MPH
96H 28/0600Z 11.8N 144.4W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 29/0600Z...DISSIPATED

$$
Forecaster Pasch

[Sciencerocks]

[cycloneye]

Tropical Depression Fourteen-E Discussion Number 4
NWS National Hurricane Center Miami FL EP142023
500 AM HST Sun Sep 24 2023

There's been little change in the depression's cloud pattern since
yesterday evening. Recent microwave and first visible conventional
satellite images depict a sheared tropical cyclone with the surface
center well north of the shapeless deep convection. The intensity
is held at 30 kt for this advisory and is based on the TAFB and SAB
satellite intensity estimates.

Although the depression is expected to track over warm oceanic
surface temperatures during the next few days, increasing wind shear
and an intruding dry and stable air mass should prevent the cyclone
from strengthening through the forecast period. Therefore, the new
official intensity forecast no longer indicates a short-term
intensification period, and now shows the depression degenerating to
a remnant low early this week, as suggested by the statistical
SHIPS intensity models and the global guidance.

The depression's initial motion is estimated to be westward or
280/13 kt. A mid-level subtropical ridge extending from the Baja
California peninsula to the western tropical East Pacific should
steer the cyclone on a generally westward track through the 36-hour
period. Afterward, a turn toward the west-southwest is expected
while the vertically shallow depression moves through the low-level
tradewind flow through dissipation. The NHC forecast track is to
the right of the previous advisory due to the initial position
adjustment and lies between the HFIP HCCA and TVCE consensus
forecasts.


FORECAST POSITIONS AND MAX WINDS

INIT 24/1500Z 15.2N 123.9W 30 KT 35 MPH
12H 25/0000Z 15.2N 126.1W 30 KT 35 MPH
24H 25/1200Z 15.1N 128.6W 30 KT 35 MPH
36H 26/0000Z 14.7N 131.0W 30 KT 35 MPH
48H 26/1200Z 14.1N 133.9W 30 KT 35 MPH
60H 27/0000Z 13.3N 136.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 27/1200Z 12.6N 140.1W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 28/1200Z 10.8N 146.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 29/1200Z...DISSIPATED

$$
Forecaster Roberts

[Sciencerocks]