EPAC: PILAR - Post-Tropical - Discussion

[Sciencerocks]

 https://twitter.com/CIRA_CSU/status/1720510025011990987

[Sciencerocks]

[cycloneye]

Tropical Storm Pilar Discussion Number 25
NWS National Hurricane Center Miami FL EP192023
400 PM CDT Fri Nov 03 2023

Deep convection associated with Pilar continues to pulse, and it
still lacks banding features. The latest satellite intensity
estimates range from 30 to 40 kt, and a recent ASCAT pass showed
peak winds in the 35-40 kt range. Based on all of these data, the
initial intensity is nudged downward to 40 kt. Pilar remains a
very compact storm and is only producing a small area of
tropical-storm-force winds north of the center.

The storm is moving quickly westward at about 17 kt. Mid-level
ridging to the north of the storm should keep Pilar on a westward
path during the next couple of days. After that time, a turn to the
west-northwest or northwest is predicted as the ridge breaks down.
There is quite a bit of spread in the models with the GFS on the far
right side of the guidance envelope and the ECMWF on the far left
side. The NHC track forecast leans closer to the left side of the
guidance since Pilar is expected to be a weakening system and will
more likely move in the low-level flow.

Pilar will likely fluctuate in strength during the next couple of
days while it remains in marginal environmental conditions. After
that time, however, an increase in southerly vertical wind shear
and intrusions of dry air should cause a weakening trend. Pilar is
now forecast to degenerate to a remnant low in 3 to 4 days.


FORECAST POSITIONS AND MAX WINDS

INIT 03/2100Z 10.1N 104.6W 40 KT 45 MPH
12H 04/0600Z 9.9N 106.9W 40 KT 45 MPH
24H 04/1800Z 10.0N 109.6W 40 KT 45 MPH
36H 05/0600Z 10.2N 112.0W 40 KT 45 MPH
48H 05/1800Z 10.8N 113.9W 40 KT 45 MPH
60H 06/0600Z 11.4N 115.3W 40 KT 45 MPH
72H 06/1800Z 12.1N 116.7W 35 KT 40 MPH
96H 07/1800Z 13.8N 119.1W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 08/1800Z 15.5N 121.6W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Cangialosi

[cycloneye]

Tropical Storm Pilar Discussion Number 26
NWS National Hurricane Center Miami FL EP192023
900 PM MDT Fri Nov 03 2023

Pilar is not much to look at tonight. The deep convective activity
near the center has been on a downward swing, though there are a few
convective clusters starting to redevelop close to the estimated
low-level center. An earlier AMSR2 microwave pass on the 37-GHz
channel also suggested that, compared to yesterday, the low-level
banding features have become more diffuse. Satellite intensity
estimates continue to range from 30 to 40 kt, and given the earlier
scatterometer data, the initial intensity is held at 40 kt, though
this may be generous.

Small Pilar seems to be struggling in its current environment, which
is honestly not all that unfavorable, with light to moderate
westerly vertical wind shear, and plenty warm sea-surface
temperatures. However, the proximity of nearby dry air surrounding
the storm has continued to periodically snuff out its convection,
preventing much organization. Thus, the forecast continues to show
the storm maintaining its current intensity, assuming dry air will
continue to keep the small cyclone in check. After 36 h, shear
begins to increase further, and weakening after that point is
forecasted. The latest NHC intensity forecast show Pilar weakening
into a remnant low by 72 h with dissipation by 120 h, but both of
these statuses could occur sooner than forecast, as suggested by the
ECMWF model.

Pilar continues to move south of due west, with an initial motion of
260/15 kt. A well-established mid-level ridge located north of the
storm should continue to steer the tropical cyclone westward for the
next few days, though with gradual slowing of its forward motion as
the ridge begins to become eroded by a deep-layer trough located
near the Baja California Peninsula. This should ultimately result in
a bit more poleward motion in Pilar into early next week. Once
again, there is a large amount of track spread, mostly related to
how vertically deep Pilar remains in the model guidance. The GFS
continues to be steadfast in maintaining Pilar as a vertically deep
cyclone, and turns the system more northwestward as the trough
weakness develops. The ECWMF (and the vast majority of its
ensembles) ultimately decouple its mid-level circulation from the
low-level one, resulting in a faster and more westward track. The
NHC track forecast favors the latter scenario, which also is closer
to the TVCN and HCCA consensus aids. This forecast is just a touch
further south and west compared to the prior one.


FORECAST POSITIONS AND MAX WINDS

INIT 04/0300Z 9.9N 106.2W 40 KT 45 MPH
12H 04/1200Z 9.7N 108.3W 40 KT 45 MPH
24H 05/0000Z 9.9N 111.0W 40 KT 45 MPH
36H 05/1200Z 10.5N 113.2W 40 KT 45 MPH
48H 06/0000Z 11.1N 114.9W 35 KT 40 MPH
60H 06/1200Z 11.8N 116.5W 35 KT 40 MPH
72H 07/0000Z 12.4N 117.6W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 08/0000Z 14.0N 119.8W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 09/0000Z...DISSIPATED

$$
Forecaster Papin

[cycloneye]

Tropical Storm Pilar Discussion Number 27
NWS National Hurricane Center Miami FL EP192023
300 AM MDT Sat Nov 04 2023

Deep convection has continued to pulse near and to the east of the
center of Pilar overnight. There were no complete ASCAT passes over
the storm tonight, but a partial ASCAT-C pass suggests the strongest
winds remain confined to the northern semicircle. The various
satellite intensity estimates range from 30-44 kt, and the initial
intensity is held at 40 kt for this advisory.

Despite moving over warm waters in a weak to moderate westerly shear
environment, the small storm has struggled to sustain convection at
times during the past couple of days due to the negative effects of
dry air. In the near term, GFS and ECMWF simulated satellite imagery
suggest this trend could continue. The upper-level environment is
forecast to become more diffluent in 24-36 h, and the GFS along with
some of the regional models show strengthening could occur during
this period. However, there are also indications that mid-level
shear will increase around the same time, which would likely result
in additional bouts of dry air intrusions. While small intensity
fluctuations seem possible during the next couple of days, the NHC
forecast follows the corrected consensus (HCCA) aid and shows no
change in strength through the weekend. Weakening is expected
beginning Monday as Pilar moves into a drier and strongly sheared
environment. Similar to the previous prediction, this forecast shows
degeneration into a remnant low by 72 h and dissipation by day 5.

A mid-level ridge to the north of Pilar is steering the storm
quickly westward (265 degrees/14 kt). This steering ridge is
forecast to become eroded by a mid-level trough near the Baja
California peninsula over the weekend. This should cause Pilar to
gradually slow down and gain some latitude, with a turn toward the
west-northwest and northwest forecast early next week. There is
large spread in the track guidance envelope beyond 24 h, with the
differences likely related to the strength and vertical depth of the
cyclone. The updated NHC track forecast is similar to the previous
one and remains close to HCCA, which falls between the stronger
(weaker) models on the right (left) side of the guidance envelope.


FORECAST POSITIONS AND MAX WINDS

INIT 04/0900Z 9.8N 107.3W 40 KT 45 MPH
12H 04/1800Z 9.8N 109.4W 40 KT 45 MPH
24H 05/0600Z 10.1N 111.7W 40 KT 45 MPH
36H 05/1800Z 10.6N 113.6W 40 KT 45 MPH
48H 06/0600Z 11.3N 115.3W 40 KT 45 MPH
60H 06/1800Z 11.9N 116.4W 35 KT 40 MPH
72H 07/0600Z 12.7N 117.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 08/0600Z 14.5N 119.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 09/0600Z...DISSIPATED

$$
Forecaster Reinhart

[cycloneye]

Tropical Storm Pilar Discussion Number 28
NWS National Hurricane Center Miami FL EP192023
900 AM MDT Sat Nov 04 2023

Pilar's satellite presentation consists of a ragged cloud pattern
with a few new bursts of deep convection near surface center. The
initial intensity is held at 40 kt for this advisory and is based
on a blend of the Dvorak satellite intensity estimates from TAFB
and SAB, and a recent SATCON analysis from UW-CIMSS.

Dry, stable marine-layer mid-level air continues to prevent Pilar
from maintaining organized deep convection, and this negative
atmospheric contribution is expected to linger during the next
several days. Additionally, southwesterly shear is forecast to
increase during the next 36 hours, and this should induce a
weakening trend by Monday. Small intensity fluctuations are
still possible through the weekend, although the official forecast
does not explicitly indicate it. The intensity forecast follows the
various consensus intensity aids closely and indicates that Pilar
will become a remnant low in 60 hours and open up into a trough in
4 days or less.

Pilar's initial motion is estimated to be westward, or 275/13 kt,
and is being steered by a subtropical ridge located to the north.
Global and regional models suggest that the above-mentioned
mid-tropospheric ridge will weaken near the Baja California
peninsula during the next day or so. This change in the synoptic
steering pattern should cause a reduction in the cyclone's forward
speed while gradually turning Pilar west-northwestward and
northwestward by Monday. There remains an increase in
across-track spread in the global models, specifically with the GFS
lying to the far right side of the guidance envelope beyond 36
hours, and the ECMWF on the far left side. The official forecast is
nudged toward the left side of the guidance suite and is close to
the NOAA HFIP HCCA corrected consensus model and the previous
forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 04/1500Z 10.2N 109.1W 40 KT 45 MPH
12H 05/0000Z 10.3N 110.9W 40 KT 45 MPH
24H 05/1200Z 10.7N 112.8W 40 KT 45 MPH
36H 06/0000Z 11.3N 114.6W 40 KT 45 MPH
48H 06/1200Z 12.0N 115.7W 35 KT 40 MPH
60H 07/0000Z 12.9N 116.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 07/1200Z 13.9N 118.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 08/1200Z...DISSIPATED

$$
Forecaster Roberts

[Sciencerocks]

[Hurricane2022]

https://imagizer.imageshack.com/img924/8395/ZU7qb5.gif

Well atleast she's trying to do something

[Hurricane2022]

[cycloneye]

Remains at 40kt.

EP, 19, 2023110418, , BEST, 0, 103N, 1100W, 40, 1002, TS

[cycloneye]

TCR candidate for change.

Tropical Storm Pilar Discussion Number 29
NWS National Hurricane Center Miami FL EP192023
300 PM MDT Sat Nov 04 2023

Pilar continues to exhibit a central dense overcast pattern, and
outer banding features have become a little better defined during
the past several hours. The latest Dvorak estimates from TAFB and
SAB have increased to 3.0/45 kt. However, an ASCAT-B pass from a
few hours ago showed peak winds around 35 kt over a small area in
the northwestern quadrant. Based on a compromise of these data, the
initial intensity is held at 40 kt, but it is possible that Pilar
could be a little stronger.

The environmental conditions appear somewhat conducive for
strengthening during the next day or so, and the models generally
show a little increase in Pilar's winds during that time. By early
Monday, however, the storm will be moving into an area of strong
vertical wind shear and notably drier air. These factors should
result in a weakening trend, and Pilar will likely become a remnant
low late Monday or early Tuesday. The NHC intensity forecast is a
touch higher than the previous one in the short term, and lies near
the middle of the guidance envelope.

Pilar is moving westward at 14 kt on the southwest side of a
mid-level ridge. A turn to the west-northwest and then the
northwest with a significant decrease in forward speed are forecast
as the ridge breaks down. Although the models generally agree on
the large-scale pattern, there are significant differences on how
vertically deep Pilar will be, which affects how much latitude the
storm gains. The GFS remains the model on the far right side while
the ECMWF is on the far left side of the guidance. Since Pilar is
expected to weaken early next week, the NHC track forecast continues
to favor the left side of the guidance envelope, in best agreement
with the ECMWF and HCCA models.


FORECAST POSITIONS AND MAX WINDS

INIT 04/2100Z 10.4N 110.5W 40 KT 45 MPH
12H 05/0600Z 10.6N 112.0W 45 KT 50 MPH
24H 05/1800Z 11.1N 113.8W 45 KT 50 MPH
36H 06/0600Z 11.8N 115.2W 40 KT 45 MPH
48H 06/1800Z 12.7N 116.3W 35 KT 40 MPH
60H 07/0600Z 13.6N 117.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 07/1800Z 14.6N 118.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 08/1800Z...DISSIPATED

$$
Forecaster Cangialosi

[cycloneye]

Tropical Storm Pilar Discussion Number 30
NWS National Hurricane Center Miami FL EP192023
900 PM MDT Sat Nov 04 2023

Pilar has become a little better organized this evening. There has
been an overall increase in banding and a couple of microwave
passes around 0000 UTC revealed a little better inner core
structure. Dvorak satellite estimates from TAFB and SAB were a
unanimous T3.0 (45 kt), and objective estimates from UW/CIMMS range
from 41 to 53 kt. Using a blend of these estimates, the initial
wind speed has been increased to 45 kt for this advisory.

Low vertical wind shear and warm SSTs along the path of Pilar could
allow for some additional strengthening overnight. Most of the
intensity guidance indeed calls for some modest strengthening, and
the official forecast follow suit. By late Sunday, however,
increasing southwesterly vertical wind shear is likely to put an
end to any further intensification. A more significant increase in
southwesterly shear is predicted Sunday night and Monday, and
steady weakening is anticipated during that time. The small
tropical cyclone is likely to succumb to these unfavorable
conditions, and Pilar is forecast to become a remnant low in 2-3
days, and dissipate shortly thereafter.

Pilar is still moving westward, but at a slightly slower forward
speed of 12 kt. A turn to the west-northwest and then northwest
with a further reduction in forward speed is expected during the
next 24-36 hours as a mid-level ridge to the north of Pilar weakens.
There are still some differences in the dynamical guidance on how
vertically deep Pilar will remain, which affects how much latitude
the storm gains. Since the NHC forecast calls for weakening to
commence by late tomorrow, the NHC track forecast favors the
southern side of the guidance. The official forecast is in best
agreement with the HFIP corrected consensus aid, which is a little
south of the simple, multi-model consensus track.

FORECAST POSITIONS AND MAX WINDS

INIT 05/0300Z 10.5N 111.6W 45 KT 50 MPH
12H 05/1200Z 10.8N 113.0W 50 KT 60 MPH
24H 06/0000Z 11.5N 114.4W 45 KT 50 MPH
36H 06/1200Z 12.3N 115.5W 40 KT 45 MPH
48H 07/0000Z 13.2N 116.6W 35 KT 40 MPH
60H 07/1200Z 14.2N 117.9W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 08/0000Z 15.3N 119.1W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 09/0000Z...DISSIPATED

$$
Forecaster Brown

[cycloneye]

Tropical Storm Pilar Discussion Number 31
NWS National Hurricane Center Miami FL EP192023
200 AM MST Sun Nov 05 2023

Pilar hasn't changed much in in organization over the past several
hours. The storm continues to have some convective banding
features along with a somewhat ragged-looking Central Dense
Overcast. Cloud tops continue to be quite cold, at -70 deg C or
colder, and the upper-level outflow pattern also remains fairly
well defined. The current intensity estimate is held at 45 kt in
agreement with subjective Dvorak values from TAFB and SAB, as well
as objective AI-ADT estimates from UW-CIMSS. ASCAT scatterometer
data from a few hours ago suggest that this estimate may be a bit
generous, since that instrument showed somewhat lower wind speeds.
However it is assumed that there was some undersampling by ASCAT of
the maximum winds in this small tropical cyclone.

Vertical wind shear over the cyclone is expected to remain fairly
low today, and this along with a warm ocean could allow for a
little more short-term strengthening. In 24 hours and beyond,
however, the dynamical guidance shows a substantial increase in
shear as Pilar begins to encounter strong southwesterly flow
associated with a broad upper-level trough to its northwest. This
increased shear should cause weakening, and the system is
likely to be reduced to a remnant low pressure area in 2 to 3
days, or possibly sooner. The official intensity forecast is
similar to the previous one and is also close to the model
consensus.

A westward motion continues for now, at a slower forward speed of
around 10 kt. Over the next day or so, the mid-level ridge to the
north of Pilar is forecast to weaken due to the influence of a low
just to the west of the Baja California peninsula. As a result,
the system is likely to turn west-northwestward to northwestward
during the next 24 hours or so. The official forecast track is
somewhat to the right of the previous NHC prediction, but is still
near the southern side of the guidance suite. This is fairly close
to the latest simple and corrected dynamical model consensus
tracks.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0900Z 10.6N 112.1W 45 KT 50 MPH
12H 05/1800Z 11.0N 113.2W 50 KT 60 MPH
24H 06/0600Z 11.6N 114.2W 45 KT 50 MPH
36H 06/1800Z 12.5N 115.1W 40 KT 45 MPH
48H 07/0600Z 13.8N 116.3W 30 KT 35 MPH
60H 07/1800Z 15.2N 117.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 08/0600Z 16.5N 118.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 09/0600Z...DISSIPATED

$$
Forecaster Pasch

[zzzh]

25 WV. This is not a 45kt TS.

[cycloneye]

Tropical Storm Pilar Discussion Number 32
NWS National Hurricane Center Miami FL EP192023
800 AM MST Sun Nov 05 2023

Pilar's cloud pattern has degraded a bit this morning, and a recent
SSMIS microwave image shows that mid-level circulation and deep
convection have decoupled to the northeast of the low-level center.
Still, the initial intensity remains 45 kt, possibly generously,
based on the latest Dvorak CI numbers and objective satellite
estimates. Although deep-layer shear is diagnosed in the SHIPS
model as being low, global model analyses suggest that stronger
mid-level southwesterly shear is occurring beneath the outflow
level. Therefore, some gradual weakening is likely over the next
day or so. After 24 hours, deeper-layer shear begins to increase to
the east of a trough, which should cause Pilar to weaken faster
through midweek. The cyclone is forecast to lose organized
convection and degenerate into a remnant low in about 2 days, and
then dissipate into a trough by day 4.

Pilar has slowed down and turned west-northwestward with an initial
motion of 285/7 kt in response to a mid-level trough extending
southwest of the Baja California peninsula. The storm is forecast
to turn toward the northwest in about 24 hours as it approaches the
trough, and continue on that heading until it dissipates in about 4
days. The NHC track forecast is close to the previous prediction
and lies between the HCCA and TVCE consensus aids.


FORECAST POSITIONS AND MAX WINDS

INIT 05/1500Z 10.8N 112.8W 45 KT 50 MPH
12H 06/0000Z 11.3N 113.7W 40 KT 45 MPH
24H 06/1200Z 12.1N 114.7W 40 KT 45 MPH
36H 07/0000Z 13.1N 115.7W 35 KT 40 MPH
48H 07/1200Z 14.6N 116.9W 30 KT 35 MPH...POST-TROP/REMNT LOW
60H 08/0000Z 16.0N 118.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 08/1200Z 17.3N 119.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 09/1200Z...DISSIPATED

$$
Forecaster Berg

[cycloneye]

And there goes the LLC.

[Astromanía]

Adios...

[Sciencerocks]

die storm die!!! End advisories nhc!

[cycloneye]

Not ending advisores yet.

Tropical Storm Pilar Discussion Number 33
NWS National Hurricane Center Miami FL EP192023
200 PM MST Sun Nov 05 2023

Just after the issuance of the previous advisory, Pilar's center
popped out from beneath the convective overcast and is now located
at least 150 n mi to the southwest of an ongoing cluster of deep
convection. Subjective Dvorak CI numbers from TAFB and SAB are now
down to 2.0/30 kt and 2.5/35 kt, respectively, and objective
estimates have fallen to between 35-40 kt. Based on these data,
Pilar's initial intensity is lowered to 35 kt. Strengthening
westerly to southwesterly shear is already taking its toll on
Pilar, and atmospheric conditions are only expected to become more
hostile over the next few days. The NHC intensity forecast is near
the low end of the guidance, most closely following the SHIPS,
LGEM, and GFS solutions, and shows Pilar becoming a remnant low by
36 hours. Since the storm remains over warm waters around 29
degrees Celsius, the forecast allows for the possibility of
convective redevelopment near the center tonight or on Monday. But
if this does not occur, Pilar could become post-tropical as early
as tonight. The remnant low is forecast to dissipate in about 3
days.

With the center becoming more apparent earlier this morning, it's
clear that a westward motion has continued (now estimated to be
275/9 kt). The dynamical models are not handling Pilar's current
motion well at all since nearly all of them show an immediate
northwestward turn, and as a result, the NHC track forecast is
along the left side of the guidance envelope and leans toward the
shallow Trajectory and Beta model (TABS), especially in the short
term. This new prediction is significantly west of the previous
forecast due to the adjusted initial position, and accounting for
Pilar's recent motion.


FORECAST POSITIONS AND MAX WINDS

INIT 05/2100Z 10.6N 114.3W 35 KT 40 MPH
12H 06/0600Z 11.1N 115.3W 35 KT 40 MPH
24H 06/1800Z 11.7N 116.2W 30 KT 35 MPH
36H 07/0600Z 12.5N 117.2W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 07/1800Z 13.7N 118.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 08/0600Z 15.0N 119.3W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 08/1800Z...DISSIPATED

$$
Forecaster Berg

[cycloneye]

The end.

Post-Tropical Cyclone Pilar Discussion Number 34
NWS National Hurricane Center Miami FL EP192023
800 PM MST Sun Nov 05 2023

After the low- and mid-level centers of Pilar decoupled this
morning, the system has failed to produce any deep convection near
the center. Although the system is still located over warm SSTs,
dry mid-level air and strong mid-level shear is likely to prevent
organized deep convection from returning. Therefore, Pilar has
become a post-tropical remnant low. The initial wind speed has been
lowered to 30 kt, based on a blend of the available satellite
estimates, but this could be generous. The system could still
produce a few bursts of deep convection during the next day or so,
but it should continue to gradually spin down. The global model
guidance indicates that the circulation will degenerate into a
trough of low pressure within 2-3 days, if not sooner.

They cyclone is moving west-northwestward at about 7 kt. A
west-northwestward to northwestward motion is expected during the
next day or two as the low- to mid-level ridge to the north of the
system weakens. Since the system has become vertically shallow, the
NHC track is along the left or south side of the guidance envelop
between the shallow Trajectory and Beta model (TABS), and the GFS
and UKMET ensemble means.

This is the last NHC advisory on Pilar. Additional information
on the remnant low can be found in High Seas Forecasts issued by the
National Weather Service, under AWIPS header NFDHSFEPI, WMO header
FZPN02 KWBC, and on the web at ocean.weather.gov/shtml/NFDHSFEPI.php


FORECAST POSITIONS AND MAX WINDS

INIT 06/0300Z 10.7N 114.8W 30 KT 35 MPH...POST-TROPICAL
12H 06/1200Z 11.2N 115.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 07/0000Z 11.9N 116.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 07/1200Z 12.9N 117.9W 20 KT 25 MPH...POST-TROP/REMNT LOW
48H 08/0000Z 13.9N 119.1W 20 KT 25 MPH...POST-TROP/REMNT LOW
60H 08/1200Z...DISSIPATED

$$
Forecaster Brown